Galvanic coating is a method of coating a metal by some other means of electrolysis.This procedure is carried out using traditional methods of immersion.After this preconditioning circuit boards are loaded into the plating bath, representing the capacitance of the dielectric, which is filled with an electrolyte and is provided with anodes (they may be soluble and insoluble) and a device for maintaining the temperature and stirring the solution.
handling fee
Transmission DC leads to that uncovered a protective mask and connected to the electrode portions of the board covered with a layer of nickel or gold of a certain thickness.Proper positioning of the anode ensures that the coating thickness is approximately uniform.
Gilding PCB is usually done using a two-step process.First, they are immersed in the bath, where electroplated nickel is applied.It uses a high current density, whereby the acid solution of the nickel layer is deposited, a thickness of 0.05-0.1 microns.This ensures strong adhesion of nickel and copper, which can reduce the porosity of the coating and also to prevent penetration of copper into the gold layer.After washing, the product is generally moved in the gold plating bath where the buildup layer is made of gold 0.5 microns from the electrolyte.
Electroplating and decoration
Even in ancient times there was a decorative finishing of artistic metal.Modern production suggests that to give any special properties of the metal surface to be used galvanic treatment.Protective coatings of the noble metals can be obtained through precipitation of metals from brine solutions by the electric current.With these coatings it is possible to save quite a long time, the color and luster of jewelry.They not only prevent the darkening of the products but also exhibit excellent polishing effect.For example, plating with gold or silver allows you to permanently preserve the color and luster of jewelry.
There are several different versions of this process, each of which involves the use of a metal:
- chrome;
- copper plating;
- galvanizing;
- nickel;
- tin-bismuth coating;
- chemical oxidation;
- chemical passivation;
- anodizing;
- electropolishing.
Chrome
This diffuse saturation of steel surface or deposition of chromium on the part of the electrolyte layer of matter under the influence of electric current.In this case, electroplating is focused on the protection against corrosion, is used for decoration or to increase the hardness of the surface.Chrome in the industry and can be used for decoration.In this case, the main purpose of the procedure - giving the metal surface beautiful spectacular shine.Detail before applying chromium to be polished.
Properties
coating hard chromium plating is characterized by heat resistance, high wear resistance, poor wettability, low friction and low ductility.Furthermore, the surface gets properties such as stability in terms of friction, ability to withstand the load distribution, as well as the disadvantages associated with fracture easily under a concentrated impact load.Galvanic coating of chromium in the form of milk has a low degree of wear resistance and hardness, low porosity.The surface is protected against corrosion, while maintaining an attractive decorative appearance.
use of chrome plating industry
main purpose for which it is used in industry, is giving details of properties such as high wear resistance, increased resistance to corrosion and reduce friction.Through this process, the steel becomes stronger, the gas is not subjected to corrosion and is not destroyed in the marine and ordinary water, nitric acid.Galvanic coating of this type leads to the fact that the surface defects become significant only because of what is required to produce the subsequent processing, as in this case no effect alignment.
Using Copper plating copper covering relevant in those cases when it is required to increase the electrical conductivity, as well as their use as an intermediate layer on the steel product before it is coated with chrome, nickel or other coating.So unable to provide a better grip, but also increase the protective ability.Copper plating is not commonly used as an independent and decorative.Due to the fact that the metal is able to prevent the formation of sparks, the product can be used in the oil and gas industry.
application of copper plating
This process is used for the coating of copper on steel products or to steel wire.Often this type of coating is used to protect areas of steel products from the cement, and processing thus exposed to those areas that are expected to continue cutting process.
metal plating in this case, are often used in the oil and gas industry to prevent the formation of sparks in the electric field for the subsequent application of multilayer coatings designed for protection and decoration, in the manufacture of printed circuit boards, to improve soldering, as well asmuch more.The surface gets color from light pink to dark red.The shades are usually not standardized.
Zinc
One of the most common methods for the protection of metal products is galvanizing.Usually it is used for the treatment of a variety of alloyed or carbon steel grades.Galvanization of this type is sufficient demand for the protection of wire products, and fasteners.Getting to moisture or the zinc surface acts as the anode, thereby slowing down the oxidation reaction, and the parent metal while receiving protection from adverse environmental factors.
Electroplating of this type can only be used after the metal product to be treated in a special way.To do so, clean them of rust, scale, hardware cooling lubricant applications.When galvanizing process is complete, the product must be subjected to clarification, i.e. it is etched with a weak solution of nitric acid, followed by passivation.So not only possible to increase the resistance of galvanized products to the negative factors but also make them more decorative, you have to give a certain luster and color.Electroplating Technology in this case involves the zinc layer thickness of 6 microns to 1.5 mm.
Nickel
Protection of metal products can be carried out using a variety of technologies.One of the most popular and common is currently the nickel.Such popularity is due to the chemical properties of nickel.It has a high resistance to corrosion in an aqueous medium, and nickel oxide prevents further oxidation of the metal.In addition, nickel poorly amenable to salts, acids and alkalis, with the exception of nitric acid.For example, the plating thickness of 0.125 mm protects the majority of industrial gases, characterized by increased aggressiveness.It is very important and such a moment: nickel plating amenable to almost all metals, so this method can be used for further processing of products.
use of nickel is appropriate for a wide range of tasks:
- the protection of metal products;
- Use as a decorative cover;
- preliminary forming layer to be subjected to further treatment;
- recovery of parts and assemblies.
coating is characterized by high wear resistance and hardness and is recommended for parts that are working in conditions of friction, especially in the absence of any lubricant is used for corrosion protection, as well as providing high-quality low-temperature solder solders, it's all spelled out in the Standard.Electroplating is especially fragile, so is not recommended to make flaring and flexible parts that have passed the procedure of nickel.It is recommended for slozhnoprofilirovannyh details.After treatment in the heat treatment conditions of a temperature of 400 degrees centigrade becomes the maximum hardness of the coating.
tin-bismuth
tin coating is characterized by resistance to sulfur-containing compounds, so it is recommended for parts that are in contact with the rubber and plastics.Among its features also include excellent adhesion to the base metal, elasticity and the ability to bend, drawing, stamping, flare, press fit and good retention in the make-up.Freshly tin coating lends itself well to soldering.
Conclusions
electro galvanized improves the conductive characteristics of parts, giving them excellent electrical insulation properties, as well as protecting against the effects of different substances.Moreover, this method allows to obtain excellent surface having a specular appearance and mimic the enamel coating.It's hard to overstate how important a modern electroplating production, since the development of technology has allowed to make the process more perfect.
