Nickel is widely used in mechanical engineering and instrument making, as well as in different industries. IN food Industry Nickel replaces tin coatings, and in the field of optics it has spread due to the procedure of black metal nickel. Nickel coat parts made from non-ferrous metals and steel to increase product resistance to mechanical wear and corrosion protection. The presence of phosphorus in nickel makes a film on hardness close to chromium film!

Nickelo procedure

Nickelock is an application to the surface of a nickel coating, which usually has a thickness from 1 to 50 microns. Coatings with nickel are brilliant or matte black, but regardless of this, provide reliable protection for metal in aggressive media (acids, alkali) and in elevated temperatures.

Before the nickelocation process, the product must be prepared. It is treated emery paper To remove the oxide film, wipe the brush, washed with water, degrease in hot soda solution and washed again. Nickel coatings are capable of losing their primary glitter over time, therefore, it is often coated with a cooler layer of nickel with a more stable chromium layer.

Nickel, which is applied directly to steel, is a cathode coating and protects the material exclusively mechanical path. The disaster of the protective coating contributes to the occurrence of corrosion steam, in which steel is soluble electrode. As a result, corrosion, destroying the steel substrate and provoking nickel coating, is formed under the coating. To prevent this metal, you should always be covered with a thick layer of nickel.

Nickel coatings can be applied to iron, copper, their alloys, as well as tungsten, titanium and other metals. It is impossible to cover with chemical nickelics such metals such as lead, cadmium, tin, lead, antimony and bismuth. With nickelting steel products, it is customary to apply the copper sublayer.

Coatings with nickel are used in different industries for special, protective and decorative purposes, as well as as a sublayer. Nickelovation technology is used to restore worn auto parts and parts of machines, coatings of chemical instruments, medical instruments, measuring instruments, household items, details, which are operated with low loads in the dry friction condition or exposure to strong alkalis.

Nickelo Types

Practice is known two species of nickelock - electrolytic and chemical. The last method is somewhat more expensive than electrolytic, however, it is capable of providing the possibility of creating a uniform in the quality and thickness of the coating on any surface sections if the condition of access to them is made.

Electrolytic nickel

Electrolytic coatings are characterized by some porosity, depending on the thoroughness of the preparation of the base and the thickness of the protective coating. To organize high-quality corrosion protection, a complete absence of pores is required, for this it is customary to pre-produce the details of the metal or to apply a multilayer coating, which is more reliable than a single layer even with a thickness.

To do this, cook electrolyte. Take 30 grams of nickel sulfate, 3.5 grams of nickel chloride and 3 grams of boric acid per 100 milliliters of water, this electrolyte pour into the container. Nickel anodes need to be lowered to electrolyte nickelocating.

Between nickel electrodes should be suspended on a wire item. Wires coming from nickel plates must be connected together. Details are connected to the negative pole. The current source, and the wires to the positive. Then you need to enable the row to the circuit to adjust the current and the milliammeter. Choose a source of direct current, which has a voltage not more than 6 V.

Current must be included in approximately twenty minutes. Then the item must be removed, rinse and dry. The product is covered with a matte layer of nickel of grayish color. In order for the protective coating to be shine, it must be polished. However, when working, remember the essential deficiencies of electrolytic nickelics at home - uneven deposition on the embossed surface of nickel and the impossibility of coating deep and narrow holes, as well as cavities.

Chemical nickelics

In addition to the electrolytic method, you can use another, very non-futured way To coating iron or polished steel, a thin but durable layer of nickel. It is customary to take a 10 percent solution of zinc chloride and gradually add to the nickel sulfate solution until the liquid becomes bright green. After that, the fluid should be heated to a boil, it is better to use a porcelain vessel for this.

At the same time, a characteristic torment appears, but it does not affect the process of nickelting of the details. When you bring the fluid to a boil, it is necessary to lower the object to it that is subject to nickel. Pre-clean the item and degrease. The product should be boiled in a solution closely, add distilled water from time to time as it evaporates.

If you notice during boiling that the liquid has changed the color of bright green to weakly green, then you need to add some nickel sulfate to obtain the original color. Upon the expiration of the specified time, get the product from the solution, rinse in water, in which a little chalk is dissolved, and dry carefully. Steel or polished iron, covered in such a nickelting method, is a protective coating very firmly.

At the heart of the chemical nickelocation procedure is the reaction of nickel reduction from an aqueous solution of its salts with the help of sodium hypophosphite and other chemical reagents. The solutions that are used for chemical nickelition are acidic with a pH of 4-6.5 and alkaline with a pH indicator above 6.5.

Acid solutions are advisable to use for coating of ferrous metals, brass and copper. Alkaline are designed for stainless steel. An acidic solution compared to alkaline gives a smoother surface to a polished part. Another important feature of acid solutions is the smaller probability of a self-discharge when the threshold of the operating temperature is exceeded. Alkaline solutions guarantee a more reliable adhesion of nickel film with basic metal.

All aqueous solutions for nickels are universal, that is, suitable for all metals. For chemical nickelics take distilled water, but you can use condensate from household refrigerator. Chemical reagents are clean - with the designation on the label "h".

The sequence of the manufacture of the solution is as follows. All chemical reagents, with the exception of sodium hypophosphite, must be dissolved in water using enameled dishes. Then heat the solution to the operating temperature, dissolve the sodium hypophosphitis and place the parts into the solution. With the help of one liter of the solution, it is possible to act the parts that have the surface area of \u200b\u200bup to 2 dm2.

Black coatings

Nickel black coatings are used with a special and decorative goal. Their protective properties are very low, so they are applied to apply on the sublayer from ordinary nickel, zinc or cadmium. Steel products need to be pre-galvanized, and copper and brass are nickel.

The black nickel coating is solid, but fragile, especially with a considerable thickness. In practice, stop at the value of 2 microns thickness. Nickel bath for applying such coatings, as a rule, contains a large number of Rodanid and zinc. The coating is present close half of nickel, and the remaining 50% is sulfur, nitrogen, zinc and carbon.

Baths of black nickelocating aluminum or steel is made to prepare, dissolving in warm water all components and filtering with filter paper. If, when dissolving boric acid, difficulties arise, it is separately dissolved in water, which is heated to 70 degrees Celsius. Obtaining deep black depends on right choice Current density values.

Nickelo baths

The workshops are widely used with a bath, which consists of 3 main components: boric acid, sulfate and chloride. Nickel sulfate is a source of nickel ions. Chloride significantly affects the operation of the anodes from nickel, its concentration in the bath is definitely not normalized. In the haylicy baths, a strong passivation of nickel is performed, after which the content in the nickel bath decreases, and the result is to reduce the current yield and the drop in the quality of coatings.

Anodes in the presence of chlorides are dissolved in sufficient quantities for the normal flow of copper or aluminum nickel. Chlorides increase bath conductivity and its functioning during zinc contamination. Boric acid helps maintain pH at a certain level. The effectiveness of this action depends to a large extent on the concentration of boric acid.

Sodium chloride, zinc or magnesium chloride can be used as chloride. Everywhere applied sulfate baths Watts, which contain electrically conductive salts as an additive, which increase the conductivity of the baths and improve the appearance protective coatings. We are most applied among these salts magnesium sulfate (close 30 grams per liter).

Nickel sulfate is most often administered at a concentration of about 250-350 grams per liter. IN lately There was a tendency to limit nickel sulfate - less than 200 g / l, which helps noticeably reduce the loss of the solution.

Boric acid concentration is 25-40 grams per liter. Below 25 g / l increases the trends to the rapid latching of the bath. And exceeding the permissible level is considered unfavorable due to the possible crystallization of boric acid and sedimentation of crystals on the walls of nickel bath and anodes.

Nickel bath works in different temperatures range. However, nickelting technology at home is rarely applied at room temperature. From the coatings that are applied in cold baths, nickel often flashes, so the bath must be heated at least up to 30 degrees Celsius. Current density is chosen experimentally so that the fourth of coatings did not occur.

Sodium bath run safely in a wide range of pH. Previously, pH was maintained at 5.4-5.8, motivating smaller aggressiveness and higher bathing abilities. However, high pH values \u200b\u200bprovoke a significant increase in stresses in nickel coating. Therefore, most bath pH is 3.5-4.5.

Nickelo's subtleties

The adhesion of nickel film with metal is relatively low. This problem It can be solved by heat treatment of nickel films. The procedure of low-temperature diffusion is to heat the talked products to a temperature of 400 degrees Celsius and the detail excerpt for one hour at this temperature.

But remember that if the details that are covered with nickel were hardened (fishing hooks, knives and springs), then at a temperature of 400 degrees, they can be released, losing hardness - their basic quality. Therefore, low-temperature diffusion in such a situation is carried out at temperatures closely 270-300 degrees with an excerpt to 3 hours. Such heat treatment is capable of increasing the hardness of the coating with nickel.

Modern nickel baths require special equipment for nickelting and mixing an aqueous solution to intensify the nickelting procedure and reduce the risk of pitting - the occurrence of small recesses in the coating. The mixing of the bath with itself entails the need to create continuous filtering to eliminate contaminants.

Stirring with a movable cathode rod is not so effective as use for this purpose. compressed air, and among other things, requires a special ingredient, which eliminates foaming.

Removal of nickel coating

Nickel coatings on steel is taken to remove in baths with dilute sulfuric acid. Add to 20 liters cold water Portions of 30 liters of concentrated sulfuric acid with constant stirring. Control so that the temperature does not exceed 60 degrees Celsius. After cooling to room temperature, its density should reach 1.63.

In order to reduce the risk of sewing the material from which the substrate is made, the glycerin is added to the amount of 50 grams per liter. Baths are customary made of viniplast. Products are hung on the middle bar, which is connected to the plus source of the current. The rods on which lead sheets are fixed are connected with a minus current source.

Make sure that the bath's temperature does not exceed 30 degrees, as the hot solution on the substrate acts aggressively. The current density should be 4 A / DM2, but a change in voltage within 5-6 volts is allowed.

Add a concentrated sulfuric acid at a certain time to maintain a density of 1.63. To prevent the bath dilution, immerse the products in the bath after their pre-drying. Control of the process of special labor does not represent, because the density of the current at the time of removal of nickel drops sharply.

Thus, nickelition is the most popular galvanotechnical process. Nickel coating is characterized by hardness, large corrosion resistance, a balanced price of nickelting, good reflective abilities and specific electrical resistance.

With prices for nickel production, you can familiarize yourself with.

Application of nickel, as well as copper, is one of the mandatory procedures in the preparation of the product under the target finishing coating. There are many electrolytes for applying nickel. It is based on the methods of application, modes, quality of coating and composition. If you decide to do the electroplating, you can not do without nickel.
Nickel itself is not often a target. As an anti-corrosion coating, it is not the best candidate, in this case there is more zinc and chrome, due to their chemical properties and the ability to "delay" the oxidation of iron, inclined to rust, on itself. how decorative coating Nickelock is used more often, but in view of its chemical instability, if necessary, apply the color of the "white" metal, often choose a palladium coating or rhodium.

Our company uses galvanic nickel and chemical (immersion nickel.
The simplest nickel solution is

Solution of acidic (sublayer) nickelon.

The electrolyte of sour nickelocation is used as the first metal coating after cleaning and polishing the product. It can be considered "glue" or the basis for which then we put all other metals. The thickness of the coating from such a solution does not exceed 1 μm, and the rate of deposition 1-2 μm / min. The duration of excerpts in the bath of sour nickelting is no more than 1 minute. This is due to the fact that acidic nickel gives fragile and dark precipitation on large thicknesses. But, nevertheless, put a thin layer of acidic nickel is necessary. Some components of its composition provides micro-descending surfaces for high-quality adhesion coverage, at the same time, causing a thin layer of fresh nickel, we provide good quality Adhesion for the next coating with copper or brilliant nickel. The electrolyte of sour nickelon is very stable in time and racks to pollution.

Electrolyte shiny nickelocation.

The electrolyte of shiny nickelocation is used to microwave the surface of the product. Compared with shiny copper, it gives less mirror sediments. The rate of increases of thickness and the working density of the current is also significantly lower, but this electrolyte is necessary for finishing product processing. It is necessarily used to obtain finishing precipitation with a thickness of up to 15 microns. Or, with a coating thickness of 3-6 μm as a high-quality substrate for galvanic or immersion gold.
Very good results, this solution demonstrates in drum and bell tanks.

Electrolyte chemical (immersion nickelting.

Chemical nickelics is used in the processing of complex products. Works without an external current application. Uniform extension of unbalanced nickel in all points of the product surface, provides solid, semi-fiber coating. Often, this solution is used to protect against corrosion by increasing nickel in a thickness of 6-30 microns. The use of chemical nickelition is limited by the source material of the part. Chemical nickel plating - a solution is hot, which does not always allow to use it for plastics. Also, in the process of work, the chemical nickel can land metal in the volume of fluid, and not only on the part, that is, it may turn out that the entire volume of the solution is disposable.
We use several types of chemical nickelocks: alkaline and acid. The principle of operation they have the same, quality of coating, compositions and mode of operation are significantly different. What a solution for chemical nickelics to use is solved depending on the product.
In addition to the listed species of nickel, there is still a solution of black nickel.

Black nickel.

Black Nickel is the most black coating of all that can be obtained galvanically. Black chrome, black rhodium, black rutments - all these dark gray coatings. Really black coating is only black nickel. If we consider the composition of this coating, it is not a completely nickel sediment, for obtaining a dark coating, additional components are introduced into a solution of nickel salts. If you want to get black - this is your option. If one is huge minus in black nickel: this coating is absolutely not resistant to abrasion. So much so that if you take a black nickel coated with black nickel several times, the galvanic coating can be erased. So the most beautiful black color of all galvanic coatings must be protected by varnish. Or put on the shelf and afar to admire the perfection of black nickel.
There are several more types of galvanic nickel. They are not constantly used, but only as needed. The main tasks is performed by the listed nickelon bath line.

If you need to navigate in nickel coating prices, you can use the plate below, while it is necessary to remember that each product before applying the galvanic coating must be examined by the technologist and the technical task to cover must be approved by the customer.

Prices for nickel products to order:

Examples of nickelting products:

Nickelting coins "Sochi 2014"

Coins "Sochi 2014", coating nickel brilliant 3 μm. Cost coating 1 coins 12 rubles (batch of 2000 pcs).

If you have questions about nickel, we will be happy to answer you by phone or by email.

Hello everyone! The purpose of the article is to show the nickel process from all possible parties. Namely, how to achieve high Quality covers, not too much will spend on consumables And safely produce galvanic work. We also make our own electrolyte from scratch if possible, instead of buying special chemical reagents.

If you are already familiar with the process of abundance, note the following that this process It has significant differences. Nickel is not very well soluble (if it dissolves at all) in vinegar without special activators.

Nickelock can be used in a variety of cases, for example:

• Create an anti-corrosion coating that protects the main metal from oxidation and corrosion. It is often used in the food industry to prevent food pollution with iron.
• Increase the solidity of the subject covered and thus increase the durability of parts of the mechanisms and tools.
• Help when soldering different metals.
• Create all sorts of options for beautiful decorative finishes.
• Significant coating thickness, can make a piece of magnetic.

Note: To get different kinds Coatings (in appearance and by properties), you will need to add additional chemical reagents and metals to obtain the desired result. The reagents will change the paths of placement of atoms relative to themselves and / or other metals are added to the applied coating. If you need to get an anti-corrosion coating, do not add any chemical reagents into the electrolyte, as they can leave on the spots or make it dim.

Disclaimer - Nickel acetate, chemical compositionwhich we will make, very poisonous. The title of the article suggests that you do not need to play crazy games with the strongest acids that can leave heavy burns on the skin. With the concentrations with which we will work, the process will be "relatively safe". Nevertheless, do not forget to wash your hands, after you finish work and do not forget to properly wipe the surfaces (which or next to which) could get the remains of chemical composition.

Let's begin.

Step 1: Materials

Almost all consumables can be found in the nearest supermarket. Find a source of pure nickel is a bit more complicated, but it will not cost more than a couple of dollars. I also strongly recommend finding a power supply (AC / DC).

Materials:

• Distilled 5% vinegar;
• Salt;
• A tightening lid bank;
• 6B battery;
• Clamps "Crocodiles";
• Nitrile gloves;
• Paper towels;
• Acid Abrasive Cameo Stainless Steel and Aluminum Cleaner;

Clean nickel - you can "get" several different ways.

• Buy two nickel plates on eBay for ~ $ 5;
• In a good construction store you can find nickel plated welding electrodes;
• Most music stores sell nickel-plated guitar strings.

You can also remove nickel coils / winding with old guitar strings if you have difficulties with money. It will take a little time, it will be necessary to use nippers and pliers. The greatest amount of nickel contains strings, which consist of a steel core, which can continue to "pollute" the electrolyte.

In addition, you can use nickel-plated door handles. I would advise with caution to treat this option. All due to the fact that there is a good chance that they are simply covered with nickel-like coating.

• High voltage power supply (constant voltage). The project used the old 13.5B charger for a laptop. You can use charging for mobile phones or an old computer power supply.
• Fuse holder;
• A simple wire fuse designed for the border operating conditions of the power supply of your choice.

Step 2: Prepare the power supply

My version of the stand is quite raw, but it is effective. You can (and possibly follow) make a small box with a can, fuse and two terminals, which are displayed outside, to which crocodiles are attached to connect to the power supply.

In case you use charging for mobile phoneYou will need to perform the following actions:

• Cut the barrel-shaped plug.
• Separate two wires and shorten one of them by 5-8 cm. This will help prevent a random short circuit.
• Clean about 6 mm wires from insulation.
• Speak to one of them the fuse holder and install a fuse in it.

In the same case, if you use a laptop charging will need to do the following:

• Cut off the barrel plug;
• Using the blade, delete outdoor isolation. Most of the charging have one insulated wire that wrapped in a variety of copper wires without isolation.
• Twist copper wires without isolation together, forming one core. It will be "earth."
• Skip the holder of the fuse.
• Clean about 6 mm insulated wire and link about the wires using a plastic clasp or isolate, so it does not be short with a bare wire.

Much more complicated to turn the computer power supply unit into the desktop BP. The search engine to help you, you will probably find a couple of articles in which everything is striking.

Note relative to polarities

When conducting the nickel process, it is necessary to determine the polarity of the conclusions in advance. Polarity can be defined using a multimeter (voltmeter mode). If you do not have an appliance at hand, you can mix the pinch of salt with a small amount of water. Take one of the "crocodiles", connect it to one wire and lower it into water. Repeat a similar procedure with another wire. The crocodile, around which bubbles will occur and will have a negative polarity.

Step 3: Cooking Electrolyte

In principle, you can buy various nickel salts, but there is no spirit of the inventor. I will show how you can make acetate nickel, much cheaper than buying Chem. Reagents in the store.

Fill the bank with distilled vinegar, leaving about 25 mm from the top. Solubam a little salt in vinegar. The amount of salt is not so important, but you should not overdo it (pinching should be enough). The reason why we add salt, lies in the fact that it increases the electrical conductivity of vinegar. The greater the current, which flows through vinegar, the faster we can dissolve nickel. However, too much the current will lead to the fact that the thickness of the coating will be mercilessly low. Everything needs to be done with savings.

Unlike copper, nickel will not turn into an electrolyte, simply leaving for a while. We need to dissolve nickel with electricity.

We place two pieces of clean nickel into vinegar with salt in such a way that parts of both pieces look out from the solution (were in the air) and at the same time did not touch each other. Fulfill the "crocodile" on one piece of nickel, after which we connect it to a positive conclusion (the polarity we defined in the last step). Secure the second "crocodile" on another piece of nickel and connect it to the negative output of the power supply. Make sure that the clamps do not touch the vinegar, as they dissolve in it and will lead the electrolyte into disrepair.

Around the source of nickel, which is connected to the negative conclusion will begin to form bubbles of hydrogen, and around the positive - bubbles of oxygen. Speaking in truth, a very small amount of gaseous chlorine (salt) is also formed on a positive terminal, but if you did not put a significant amount of salt or use a low voltage, then the chlorine concentration, which dissolves in water will not exceed the permissible limits. Work should be carried out on the street or in a well-ventilated room.

After some time (in my case, about two hours), you will notice that the solution has become light green. This is acetate nickel. If you got blue, red, yellow or any other colors, it means that the source of nickel was not clean. The solution should be transparent if it is muddy - the source of nickel was not clean. The solution and "nickel sources" can be warm during the process - this is normal. If they have become very hot to the touch, turn off the power, let them cool for an hour, and then turn on the power again (repeat if necessary). You may have added too much salt, which increased the current and power dissipated in the form of heat.

Step 4: Preparation of the surface for the coating

NOTE. Some metals such as stainless steelDo not allow direct nickel. First, you need to create an intermediate copper layer.

The final result will depend on the purity of the surface on which the nickel coating will be applied. Even if the surface looks clean, it still needs to be cleaned (soap or a cleaning agent in which acid is included).

You can additionally clean the surface by reverse galvanic decomposition (i.e., the "electrochip") for a few seconds. Attach the object to the positive conclusion, the "empty wire" to the negative output and leave them in the solution of vinegar salts by 10-30 seconds. This will lead to removal of residual oxidation.

Large surfaces can be cleaned with fine steel brushes and vinegar.

Step 5: It's time for galvanization

In this step, 6V battery will be used as a power source. Lower voltage (approximately 1 c) will make it possible to achieve a better, more brilliant and smoother coating. For electroplating, you can use the power supply of a higher constant voltage, but the result will be far from ideal.

We place the source of nickel into the nickel acetate solution and connect it to the positive conclusion of the battery. Secure another clamp on the object to be nicked and connect it to the negative battery output.

We place the object into the solution and wait about 30 seconds. Get it, turn 180 degrees and put it back into the solution for another 30 seconds. You need to change the location of the clamp to cover the entire surface. Unlike copper coating, the clamp should not leave the labels of "burns".

The solution around the object must be bubble.

Step 6:

Nickel is not oxidized at room temperature and does not fade. You can slightly polish the surface to get a bright shine.

If nickelock is not so brilliant, as I would like, polish it with a means that does not contain wax or oil, and then re-install the electroplating.

Adding a small amount of tin during the initial coating will change the color (tin gives the color of white metal, such as silver). Many metals can be electrically dissolved in vinegar, like nickel. Two main metal that cannot be electrically dissolved in vinegar is gold and silver (believe me, I tried). From the past experiment, I have a little copper electrolyte, which I mixed with a nickel solution. The result is a matte, dark gray, very solid surface, which is similar to the school board.

If you are not an experienced chemist, be very careful, adding random chemicals to a galvanic bath - you can easily create some kind of toxic gas ...

That's all! Thanks for attention.

Nickelo, technical process of application to the surface of metals b. or m. Thin film of metal nickel or nickel alloys; The purpose of this application is to reduce metal corrosion, increase the hardness of the outer layer, increase or change the reflectivity of the surface, inform it more beautiful view. The Bettger received for the first time in 1842 and industrialized in the United States since 1860, nickelition was currently becoming one of the most widely learned industries of the methods of coating metals.

Existing numerous nickel production methods can be divided into two main groups: Methods Contact and Methods galvanotechnical; Currently, they are particularly often resorted to the latter. Nickel film application applies to surfaces various metals, and in accordance with the nature of the nickelocation, they can be divided into groups: 1) copper, brass, bronze, zinc, 2) iron, 3) tin, lead and alloys of type of Britain-metal, 4) aluminum and aluminum alloys. Nickel films represent quite satisfactory iron protection from rusting in interior.

However, they are insufficient open-air; In addition, hot fats, vinegar, tea, mustard act on polished nickel-plated surfaces, as a result of which the dining room and kitchen nickel-plated dishes are covered with spots. In cases where it takes quite reliable protection against weather impact and at the same time, the elegant appearance of the nickel-plated surface, on the iron d. B. There is a double film - zinc, and then nickel. This double coating method (zinc, and then nickel) is also applied in relation to so-called. Corset steel. If necessary, it is particularly resistant films, such as nickel and platinum, and platinum are layered at the same time, and the content of the latter is gradually increased from 25% to 100% and finally calculate the object in the hydrogen jet at 900-1000 ° C. Close-ups, for example, boilers for cooking, centrifuges centrifuges or fans, if in economic conditions can not be made of pure nickel, but not enough rack with a nickel film over the gland or copper, we are lined with a layer of lead in several mm, and on it with nickel layer in 1-2 mm. The rusting of iron and steel nickel-plated products is explained by the presence of electrolyte remaining in thin pores of the nickel film. This phenomenon is eliminated if the products in front of the nickelice are withstanding in oil at 200 ° C, in cooling to degreases, weakly messed, then rolled into the lemon-acid nickel bath with a weak current and finally dried in a closet at 200 ° C; Then the moisture is removed from the pores, which are blocked by oil in them.

There are a number of proposals to impose double protective films on cast iron, iron or steel sheets, wires and strips in the reverse order of the above, i.e., first cover the products with fine nickel film with contact or electrolytic method, and then immersed in a bath with molten zinc or tin (Vivien and Lefebra, 1860). It is also proposed to add a certain amount of nickel into an alloy of 25-28 kg of zinc, 47-49 kg of lead and 15 kg of tin, serving to cover iron sheets with a hot way. The resistance of aluminum surfaces and its alloys against salt and sea water m. B. It has been achieved by electroplated precipitation on them, after cleaning them with sandstone, successive layers: nickel with a thickness of 6 microns, copper in 20 microns and then again nickel in 50 microns, after which the surface is polished. Aluminum resistance against 15% natar alkali is achieved by a nickel film of 40 microns with thickness. In some cases, the coating is not clean with nickel, but alloy, such as nickel-copper; For this, the electrolysis is carried out in a bath containing cations in the ratio of the required alloy; The precipitated film is then translated into the alloy heating the product to the red-calin heat.

Contact nickel. Steel items, according to the indication of F. Stolba (1876), after polishing and proper degreasing, boiled in a bath from a 10-15% aqueous solution of a pure zinc chloride, to which a nickel sulk acid is added to the formation of a green mud from the main nickel salt. Nickelting lasts about 1. After that, the item is riveted in water with chalk, and the bath, after filtration and the addition of nickel salt, can be applied again. The resulting nickel film is thin, but it lasts firmly. To increase the temperature of the bath, it is proposed or to conduct a pressure process (F. Stolba, 1880) or apply a bath with a concentrated zinc chloride solution. In order to avoid rusting items, they are maintained for 12 hours. In lime milk. A more complex bath for iron objects, pre-deposited in a bath of 250 g of copper sulfur in 23 liters of water with several drops of sulfuric acid, contains 20 g of wine stones, 10 g of ammovye, 5 g sodium chloride, 20 g of chlorine tin, 30 g of nickel sulfur and 50 g double sulfuric acid nickel-ammonium salt.

Galvanic nickel. Deletion nickel bath m. B. Warned enough easy dissolution of nickel anodes. Folded, and in particular from clean nickel, the anodes are dissolved difficult and therefore, with technical nickelock, they use nickel bars as anodes containing up to 10% iron. However, such anodes lead to precipitation on the subject of iron, and the presence of iron in the nickel film entails a number of nickel defaults. As indicated by Calgan and Hammog (1908), it is impossible to obtain when anodes with an iron precipitate, quite free from the latter. But the precipitate of nickel will contain only 0.10-0.14% of iron, if in the anodes the iron content is reduced to 7.5%; The iron content in the sediment can still be reduced, entering into the anodes into tissue bags, while the rotation of the electrodes leads to an increased iron content in the sediment and to a decrease in its output. The presence of iron in the nickel film leads to deposition of precipitation with gradually decreased content of iron and therefore inhomogeneous in relation to mechanical properties at different depths; K. Enhenan (1911) considers this heterogeneity the only reason for the easiest decavility of nickel films. The presence of iron m. B. Cause of a number of other nickeloral vices (see Table), for example, ease of rusting of the films.

Vice	The cause of the occurrence	Measure struggle
Nickel's precipitation does not occur, there is no gas formation	Current source does not work	Check and renewing the source of energy
	Wires adventrated wrong	Switching wires
	The bath is too cold	Heating the bath to a temperature above 15 ° C
	Bath too sour	An aqueous solution is added ammona alcohol or aqueous suspension of nickel carbon dioxide with continuous stirring and frequent test on conpo-paper
	Bath contains zinc	The bath is made alkaline by carbon dioxide, is stirred for several hours, filtered and acidified with 10% sulfuric acid.
Incomplete coating of the subject with nickel film	Insufficient current	Items are suspended at equal distances from the anodes, the bath is heated at least as to 20 ° C
	Very deep concavity of the surface of the subject	Mounted small auxiliary anodes introduced into the deepening of the subject
	Bath alkalinity	Careful bleeding of a bath with 10% sulfuric acid when stirring and a constant test of lactium paper
Easy cleavage of white or yellow-nickelpolishing films	Pollution of surface surfaces by oxides and fat	Additional surface cleaning of objects
	Too much voltage (above 4V)	Increase the number of nickelectable objects or reduce the voltage to 2.5-3 V
	Too big acidity bath	Neutralization by ammonic alcohol or aqueous suspension of nickel carbon dioxide
	Poverty bath Nickel	Removal of the part of the electrolyte and the addition of nickel salt, while the bath does not become normal green
	Inappropriate viscosity and surface bath tension	Supplement of glycerin or amyl alcohol, or plant decoctions, or other colloids
	Selection of hydrogen ions	Supplement of oxidizing agents or hydrogen absorbers; Application of asymmetric alternating current
	Non-compliant surface preparation of objects	Message to surfaces of roughness, mechanical or chemically, coating with a thin layer of nickel from a hot solution of nickel chloride or a cold concentrated solution of ethyl-sulk nickel
Loofing of the nickel film or a breaking of it when bending and tensile items	The presence of capillary electrolyte	Dry and heating items up to 250-270 ° C
Insufficient workability of sheets covered with a thick layer of nickel	Probably the same	Flushing, drying without air access and finally heating to weak red-calin heat
The surface in the sumps and the film is permeated with countless	Dust and particles fibers floating in the bath	The bath is boiled, filtered and installed in it the correct reaction
	The formation of gas bubbles	Tapping on the current-standard rod. Bubbles remove; Install the weakly acidic reaction
Rudeness and irregular surface	Hydrogen release	Introduction of free chlorine binding hydrogen in a gaseous form by the times of the passed jet or in aqueous solution; With a slightly smaller success of chlorine m. b. replaced by bromine; Extremely recommended adding cobalt chloride solution
Insufficient film flexibility	High resistance bath	Sodium salt additive
Yellow film; The surface becomes matte, and then gets yellow and dark yellow color	The presence of iron impurities in the bath, the content of which rises in old baths	Avoid old baths, not too moving the bath, work with weak currents
Black Film, Dark Stripes in Places Loading With Proper Top Density	Contents in the bath of foreign metals (up to 1%)	Removal of foreign metals
	Lack of conductive salts	Adding conducting salts in an amount of 2-3 kg per 100 liters of baths: ammonia, potassium chloride and sodium chloride give an increase in conduction at 84.31 and 18%, respectively
	Poverty Bath Salt Nickel	Supplement of nickel salt
Tan surface	Too much bath conductivity due to the excessive fortress	Bath concentration control (for example, density constancy at 5 ° B) and current density
Strip formation	Pollution made by polishing circle in small recesses	Elimination is difficult; It is achieved to a certain degree instantaneous immersion in the boiler with liquor or mechanical wipes
	Changes in concentration and emergence of fluid flows	Reducing current density and bath temperature
Fifth education	Insufficient cleaning of finished talked products	Careful flushing in flowing water after nickelocation, then immersion in boiling quite clean water, shaking products and drying in heated sawdust
Definition of nickel film to the gland	The presence of rust	Careful liberation from rust. Galvanic application of an intermediate layer from a cyancali bath, after which the film thickens in an acidic bath

The electrolytic bath for nickelings is compiled by ch. The double nickel-ammonium salt, and weak acids are added to eliminate the main salts. A large acidity of the bath leads to more solid films. It must be borne in mind that the technical nickel vigoros is not suitable for baths, since it often contains copper; It should be removed by transmitting hydrogen sulfide through the aqueous solution of the vapor. The chloride salts are also used, but at sulphate baths, the precipitates are harder, whiter and more rack than with chloride. High resistance of the nickel bath is beneficial to reduce the addition of various conductive salts - especially the ammonia and sodium chloride - and heating. Neutralization of excess sulfuric acid in old solutions is successfully produced by carbon dioxide nickel, which is obtained from a warm aqueous solution of a nickel sulfate precipitated by soda. For the whiteness and smoothness of the films, a large number of proposals were made to add various organic acids to the nickel bath (wine, lemon, etc.) and their salts, for example, acetic and alkaline earth metal salts (Kate, 1878. ), Propionic nickel, Born-Wine-colored alkali metal salts. If necessary, it is proposed to obtain thick nickel sediments to add borne, benzoic, salicylic, gallium or pyrollic acids, and in addition 10 drops of sulfur, ant, lactic acid for 1 liters of baths to prevent the polarization on the product. As Puell (1881), an increase in benzoic acid (31 g on a bath of 124 g of nickel sulfate and 93 g of a nickel lemon acid of 4.5 liters of water) eliminates the need to use chemically pure salts and acids. The nickel precipitate has good properties also with a simple bath from nickel-ammonium sulfate, but under the alkalicity of the solution, which is achieved by adding ammonia. Very good precipitates are obtained from a neutral solution of fluorite-boron nickel at room temperature (at temperatures above 35 ° C, the solution decomposes with the formation of an insoluble base salt) and current density of 1.1-1.65 A / DM 2 . We give several bath recipes. 1) 50 h. Sodium bisulfite, 4 h. Nitric acid oxide nickel and 4 h. Concentrated ammonia alcohol is dissolved in 150 hours. Water. 2) 10-12 hours. Nickel sulfate, 4 h. Double nickel-ammonium sulfur salt, 1-3 hours. Boric acid, 2 h. Magnesium chloride, 0.2-0.3 h. Limonous ammonium, fills up to 100 hours . (total) water. Current density 1.6 A / DM 2 Deals the film at a speed of 2 μm / h; Raising temperatures up to 70 ° C, you can reduce the resistance of the bath in two or three times and the speeds of nickel. 3) The electrolyte of 72 g of the double nickel-ammonium sulfate salt, 8 g of nickel sulfate, 48 g of boric acid and 1 liter of water is particularly favorable for softness and incapacity of the sediment, since reduces the release of hydrogen.

Obtaining nickel films special view . 1) the white film on zinc, tin, lead and Britain-metal is obtained in a bath of 20 g of a double nickel-ammonium sulk acid salt and 20 g of nickel carbon dioxide dissolved in 1 liter of boiling water, and neutralized at 40 ° C of acetic acid; The bath must be maintained neutral. 2) the matte-white film is obtained in a bath of 60 g of a double nickel-ammonium sulk acid salt, 15 g of a recrystallized sulfuric acid of nickel, 7.4 g of the ammonia, 23 g of sodium chloride and 15 g of boric acid for 1 liter of water; Bath d. B concentrated to 10 ° Bẻ; Voltage from 2 to 2.5 V. 3) The black film is obtained on the surfaces, carefully skimmed or coated with a thin layer of white nickel by electrolysis in a bath of 60 g of a double nickel-ammonium sulfur salt, 1.5 g of rodanoy ammonium and about 1 g of sulfate zinc on 1 liter of water 4) The black film is also obtained in the electrolyte from 9 g of a double nickel-nickel-ammonium sulfate salt in 1 liter of water, followed by adding 22 g of rodanny potassium, 15 g of carbon dioxide and 15 g of white arsenic, pre-dissolved in ammonium carbon dioxide; The depth of black tone grows with a content of arsenic solution. 5) Deep blue film is obtained in a bath from equal parts Double and simple sulphate salts of nickel, brought to 12 ° Bẻ, and for a liter, add 2 h. Ammonian bravery of a laccic root; Electrolysis lasts 1 hour at 3.5 V, and then another 1/2 hour at 1.4 V. 6) Brown film is obtained: the electrolysis at a voltage of 0.75-1 V is carried out in a bath of 180 g double nickel-ammonium sulk acid salts and 60 g of sulfate nickel dissolved in the possibly small amount of boiling water added to 50 cm 3 and mixed with solutions of 30 g of nickel sulfate and 60 g of rodanny sodium, each in 0.5 liters of water, after which the solution is added to 4, 5 liters The resulting film of black is attached brown tint, immersion for a few seconds in a bath of 100.6 g of iron perchlorate and 7.4 g of hydrochloric acid in 1 liter of water: after washing and drying, the surface of the product for fixing the tone is varnished.

Nickelting aluminum and its alloys. Several processes are proposed. 1) Preparation of the surface of aluminum products consists in degreasing, then cleaning the pumice and finally immersed in a 3% aqueous solution of potassium cyanide; After electrolysis in the nickel bath, the products are washed with cold water. 2) After washing with a 2% solution of potassium cyanide, the products are immersed in a solution of 1 g of iron chloride (ferrochloride) by 0.5 liters of water and technical hydrochloric acid, while the surface does not become silver-white, and then nickened for 5 minutes. At voltage 3 V. 3) Polishing of products, removal of polishing composition of gasoline, shutter speed for several minutes in a warm aqueous solution of sodium phosphate, soda and resin, washing, immersion for a short time in a mixture of equal parts of 66% sulfuric acid (containing somewhat chloride of iron) and 38% nitric acid, new flushing and electrolysis in a bath containing nickel salt, bitter salt and boric acid; Voltage 3-3.25 V. 4) according to J. Kanaka and E. Tassilli: Product Drancing with potassium alkali, brushing in lime milk, 0.2% cyanque bath, Bath with 1 g of iron in 500 g of hydrochloric acid and 500 g of water, flushing, nickelting in a bath of 1 liters of water, 500 g of nickel chloride and 20 g of boric acid at a voltage of 2.5 V and current density 1 A / DM 2, finally polished matte-gray sediment. The iron bath serves to cut the aluminum surface and the strength of the strength, with what the film on the metal is held. 5) according to Fisher, nickel bath is composed of 50 g of nickel sulfate and 30 g of ammovary in 1 l of water at a current density of 0.1-0.15 A / DM 2, in 2-3 hours it turns out a thick precipitate, which has a high glitter After polishing with stearin oil and Vienna lime. 6) Hot bath (60 ° C) is composed of 3400 g of a double nickel-ammonium sulfur salt, 1100 g of ammonium sulfate and 135 g of milk sugar in 27 liters of water. 7) Cold bath contains nitrogenous nickel, potassium cyanide and phosphorous ammonium.

Control of nickel film. Recognition of the composition of the metal film on the subject, by L. Lovitonu (1886), can be carried out by heating the subject in the outer flame of the Bunzen burner: the nickel film shines, it gets black defect and persistently persistent; Silver does not change in flame, but black when processing a diluted solution of sulfur ammonium; Finally, the tin coating quickly becomes from gray-yellow to gray and disappears when processing the specified reagent. Checking the quality of nickel film on iron and copper in relation to pores and flaws can be carried out using t. N. Ferrinksyl test and with special convenience with ferroxyl paper coated with agar-agar gel with iron-sinerodistic potassium and sodium chloride. Imposed in moistened form on the test surface and after 3-5 minutes. Fastened in water, this paper gives a documentary image of the slightest pores, which m. b. Saved.

Nickel Regeneration from Old Products. The removal of nickel coating with iron products and other non-emalgamized metals is carried out in the following ways: a) vapors of mercury under vacuum or under ordinary pressure; b) heating trimming with gray, after which the metal layer is easily removed by the hammers; c) heating trimming with substances that give sulfur at high temperatures) with a sudden cooling of the nickel film scores; d) processing heated to 50-60 ° with sulfur or nitric acid; Iron goes into the solution, and nickel remains almost undisguised; However, despite its simplicity, this method is not enough, since the resulting nickel retains a significant content of iron, not removed and when re-treated with acid (T. Fleteman); d) long heating when accessing air or water vapor, after which trimming is subjected to mechanical shocks and nickel bounces off; e) electrolytic dissolution: nickel iron-covered object make an anode in a bath containing carbon dioxide ammonium; If the coating consists of nickel alloy, then the voltage must be adjusted, and the copper is deposited at 0.5 V, and at a voltage of greater 2 V - nickel; At the same time, the process of iron is not extended; g) Iron or steel trimming make an anode in a bath from an aqueous solution of sodium nitrate, while the cathode consists of a coal stick; Voltage should not exceed 20 V; h) with zinc mugs nickel is removed by electrolysis of objects made by anodom in 50 ° or sulfuric acid; The acid of this concentration has a property to dissolve only nickel, silver and gold, but not other metals, if there is a current; Voltage applies 2-5 V; Iron sheets are used as cathodes, on which nickel is deposited in the form of dust; Zinc does not dissolve, at least mugs and remained in the electrolyte for a long time.

Nickel plant is used in mechanical engineering, instrument making and other industries. Nickel coat parts made of steel and non-ferrous metals to protect them from corrosion, decorative finish, increase resistance to mechanical wear. Due to its high corrosion resistance in alkali solutions, nickel coatings are used to protect chemicals from alkaline solutions. In the food industry, nickel can replace tin coatings. In the optical industry, the process of black nickeling was distributed
With electrochemical precipitation of nickel on the cathode, two main processes flow: Ni 2+ + 2e - → Ni and 2N + + 2e - → H 2.
As a result of the discharge of hydrogen ions, their concentration in the cathode layer decreases, i.e. the electrolyte is overshadic. At the same time, the main salts of nickel that affect the structure of N mechanical properties nickel coating. Hydrogen is also caused by pitting - a phenomenon in which hydrogen bubbles, lingering on the surface of the cathode, prevent the discharge of nickel ions in these places. On the coating, pits are formed and the precipitate loses a decorative look. In the fight against pitting, substances are used that reduce surface tension at the metal - mortar border.
With anodic dissolution, nickel is easily passivated. When the anodes are passivated in the electrolyte, the concentration of nickel ions decreases and the concentration of hydrogen ions is growing rapidly, which leads to a drop in current output and deterioration of precipitation. To prevent the passivation of the anodes, activators are introduced into the nickelite electrolytes. Such activators are chlorine ions, which are injected into the electrolyte in the form of nickel chloride or sodium chloride.

Be careful! The company "LV-Engineering" does not provide services for applying galvanic coatings! Our organization carries out the design of electroplating industries, the manufacture of electroplating baths and polypropylene lines, installation and commissioning works in this area.

Sulk acid electrolytes nickelics

Sulk acid nickelovation electrolytes received the greatest distribution. These electrolytes are resistant to work, if possible, they can be used for several years without replacement. The composition of some electrolytes and nickelization modes:

Structure	Electrolyte №1	Electrolyte №2.	Electrolyte №3
Nickel sulcise		280-300	400-420
Sodium sulk acid	50-70	-	-
Magnesium sulkais	30-50	50-60	-
Born Acid	25-30	25-40	25-40
Sodium chloride	5-10	5-10	-
Sodium fluorins	-	-	2-3
Temperature, ° C	15-25	30-40	50-60
Current density. A / dm 2	0,5-0,8	2-4	5-10
pH	5,0-5,5	3-5	2-3

Sodium sulphate and sulfate magnesium are injected into the electrolyte to increase the electrical conductivity of the solution. The conductivity of sodium solutions is higher, but in the presence of Magnesium sulfate, brighter, soft and easily polished precipitation are obtained.
Nickel electrolyte is very sensitive even to small acidity changes. To maintain the pH value at the required limits, buffer compounds must be applied. As such a compound that prevents the rapid change in the acidity of electrolyte, boric acid is used.
To facilitate the dissolution of the anodes in the bath, sodium chloride salts are injected.
To prepare sulphate electrolytes nickels, it is necessary to dissolve in separate containers in hot water All components. After settling, the solutions are filtered into a working bath. The solutions are stirred, the pH of the electrolyte is checked and, if necessary, corrected with a 3% solution of caustic soda or a 5% sulfuric acid solution. The electrolyte is then brought to water to the required volume. In the presence of impurities, it is necessary to produce it before starting the operation of the electrolyte, since nickel electrolytes are extremely sensitive to extraneous impurities of both organic and inorganic.
Defects during the operation of the electrolyte of shiny nickelon and their elimination methods are shown in Table 1.

Table 1. Defects during operation of sulfate electrolytes nickels and ways to eliminate them

Defect	Cause of Defect	Remedy
Nickel is not deposited. Abundant isolation of hydrogen	Low pH value	Correct the pH of a 3% solution of caustic soda
Partial coating nickel	Poor degreasing details	Improve preparation
	Improper arrangement of anodes	Equally distribute the anodes
	Details Mutually shielded each other	Change the location of the parts in the bath
Coverage has grey colour	Availability in electrolyte copper salts	Clear electrolyte from copper
Fragile, cracking coating		Treat the electrolyte activated carbon and work for current
	The presence of glaze impurities	Clear electrolyte from iron
	Low pH value	Corporate pH
Pitting education	Electrolyte pollution with organic compounds	Earn electrolyte
	Low purpose pH	Corporate pH
	Weak mixing	Stir mixing
The appearance of black or brown strips on the coating	The presence of zinc impurities	Clear the electrolyte from zinc
The formation of dendrites on the edges of the details	High density Tok.	Reduce current density
	Excessively long nickel	Enter the intermediate sublayer of copper or reduce the time of electrolysis
Anodes are covered with brown or black film	High anode current density	Enlarge the surface of the anodes
	Small sodium chloride concentration	Add 2-3 g / l sodium chloride

With nickelography, hot-rolled anodes are used, as well as non-accommodated anodes. Apply the anodes in the form of plates (cards), which are loaded into the titanium baskets. Card anodes contribute to uniform dissolution of nickel. In order to avoid pollution of the electrolyte, the anode sludge nickel anodes should be concluded in the covers of the tissue, which are pre-treated with 2-10% solution of hydrochloric acid.
The attitude of the anode surface to the cathode with electrolysis 2: 1.
Nickelting of small parts is carried out in bell tower and drum baths. With nickelting in bell tower baths, an increased content of chloride salts in an electrolyte is used to prevent the anode passivation, which may arise due to the mismatch of the surface of the anodes and cathodes, as a result of which the nickel concentration in the electrolyte decreases and the pH value decreases. It can achieve such limits in which the precipitation of nickel is terminated. The disadvantage when working in bells and drums is also a large electrolyte deposit with details from the baths. Specific rules of losses are from 220 to 370 ml / m 2.

Electrolytes of brilliant nickelics

For the protective decorative decoration of parts, shiny and mirrored nickel coatings obtained directly from electrolytes with glossy-forming additives are widely used. Composition of electrolyte and nickelting mode:

Nickel sulphate - 280-300 g / l
Chloride nickel - 50-60 g / l
Born Acid - 25-40 g / l
Sakharin 1-2 g / l
1,4-buttonediol - 0.15-0.18 ml / l
Phthalimide 0.02-0.04 g / l
pH \u003d 4-4.8.
Temperature \u003d 50-60 ° C
Current density \u003d 3-8 A / DM 2

To obtain brilliant nickel coatings, electrolytes are also used with other glossy additives: chlorine b, propargyl alcohol, benzosulfamide, etc.
When applying a brilliant coating, an intensive mixing of electrolyte with compressed air is preferably preferably in combination with the swing of cathode rods, as well as continuous electrolyte filtering,
The electrolyte is prepared as follows. In distilled or deionized hot (80-90 ° C), the water is dissolved with stirring sulfate and nickel chloride, boric acid. The electrolyte is brought by water to the working volume to be chemical and selective cleaning. To remove copper and zinc, the electrolyte is acidified with sulfuric acid to pH 2-3, the cathodes of a large area of \u200b\u200bcorrugated steel are walked and the electrolyte is worked out during the day at a temperature of 50-60 ° C, stirring with compressed air. Current density 0.1-0.3 A / DM 2. Then the pH of the solution is adjusted to 5.0-5.5, after which potassium permanangat (2 g / l) or a 30% hydrogen peroxide solution (2 ml / l) is introduced into it.
The solution is stirred for 30 minutes, 3 g / l of activated carbon treated with sulfuric acid is added and the electrolyte 3-4 is stirred using compressed air. The solution is defended 7-12 hours, then filtered into the working bath.
In the purified electrolyte, glossomy inverters are introduced: saccharin and 1,4-buttonediol directly, phthalimide - pre-soluble in a small amount of electrolyte, heated to 70-80 ° C. Rhged the pH to the desired value and proceed to work. The consumption of glossing agents when adjusting the electrolyte is: Sakharin 0.01-0.012 g / (A.H); 1,4-Butndiol (35% solution) 0.7-0.8 ml / (A.H); Ftalimide 0.003-0.005 g / (A.H).
Defects during the operation of the electrolyte of brilliant nickelocking and their elimination methods are shown in Table 2.

Table 2. Defects during the operation of the electrolyte of shiny nickelting and the ways to eliminate them

Defect	Cause of Defect	Remedy
Insufficient gloss coating	Mala concentration of glossing agents	Introduce glossomy
	The specified current and pH density is not maintained.	Adjust current and pH density
Dark color Coatings and / or dark spots	In electrolyte there are impurities of heavy metals	Selective electrolyte cleaning at low current density
Pitting	Availability in electrolyte iron impurities	Clear electrolyte and introduce an anti-portding additive
	Insufficient mixing	Enlarge air stirring
	Low electrolyte temperature	Increase electrolyte temperature
Fragile precipitation	Electrolyte pollution with organic compounds	Clear electrolyte activated coal
	Reduced content of 1,4-buttonediola	Enter the addition of 1,4-buttonediola