What is Chrome Plating, Nickel Plating, and Zinc Plating

What is electroplating

Electroplating is the process of plating a thin layer of other metals or alloys on the surface of certain metals. It uses the principle of electrolysis to attach a metal film to the surface of a metal or other material, so it can prevent metal oxidation ( Such as rust), improve wear resistance, electrical conductivity, reflectivity, corrosion resistance (copper sulfate, etc.) and enhance aesthetics. Electroplating types are mainly copper plating, gold plating, silver plating, chrome plating, nickel plating and zinc plating, etc. In the manufacturing industry, chrome plating, nickel plating and zinc plating are the most widely used methods.

What is chrome plating, nickel plating, zinc plating

Chrome Plating

Definition: chrome is a bright white metal with a bluish tint. The method of plating a chrome layer on metal or some non-metals by electrolysis or chemical methods.

Features: there are two types of chrome plating. One is for decorative purposes. It has a bright appearance and good abrasion resistance. The anti-rust ability is not as good as galvanized and is worse than oxidation. The other  is to increase the hardness and wear resistance of metal parts, this is the functionality of the part.

piston rod
nickel plating

Nickel plating

Definition: the method of plating a nickel layer on metal or certain non-metals by electrolysis or chemical methods.

Features: beautiful, can be decorated, high price, slightly complicated craftsmanship, the color is silvery white and yellow.

Zinc plating

Definition: zinc plating refers to a surface treatment technology that coats the surface of metal, alloy or other materials with a layer of zinc for aesthetics and rust prevention.

Features: low cost, general anti-corrosion, silver-white color.

zinc plating

The most basic difference between the three types of electroplating methods

  1. Chrome plating is mainly to improve surface hardness, appearance and rust prevention. The chromed layer has good chemical stability and has no effect in alkali, sulfide, nitric acid and most organic acids, but it can be dissolved in hydrohalic acid (such as hydrochloric acid) and hot sulfuric acid. Due to chrome does not change color, it can maintain its reflection ability for a long time during use and is better than silver and nickel. The process is generally electroplating.
  2. Nickel plating is mainly wear-resistant, anti-corrosion, and anti-rust. Generally, the thickness is thin. The process is divided into two types: electroplating and chemical.
  3. Zinc plating is mainly with good apperance and anti-rust. Zinc is an active metal and can react with acid, so it has poor corrosion resistance and is the cheapest of the three.
  4. The difference in cost is that chrome plating is most expensive, nickel plating is the second, and zinc plating is the cheapest. Among them, rack plating and barrel plating must be distinguished. Rack plating is expensive and barrel plating is cheap.
  5. Chrome plating surface is bright white. Nickel plating surface has a little yellowish. Zinc plating surface is silver-white (in fact, there are color zinc, gray zinc, matt chrome, bright chrome, white nickel, black nickel, etc.) these three are the most common.

About the chrome plating on piston rod of a hydraulic cylinder

The piston rod is an important part of a hydraulic cylinder. It is usually made of CK45 steel to make a solid rod or a hollow tube. The hydraulic cylinder piston rod is subject to abrasive erosion during application, which is very easy to wear. In order to improve the wear resistance of the piston rod surface, as well as to extend the service life of the piston rod, the current domestic traditional process is chrome plating on the surface. The thickness of the plating is generally 0.03mm to 0.05mm. For some special piston rods, the chrome plating thickness can even reach 0.08mm. The surface roughness Ra is 0.1μm to 0.2μm.

The plating solution is based on chromic acid and sulfuric acid as a catalyst. The advantages of the process are that the plating solution is stable, easy to operate. The quality of the chrome plating layer on the surface is relatively high, as a result, it gives the piston rod the advantages of brightness, high hardness, and excellent wear resistance. Its fatal disadvantage is that chrome-containing wastewater and exhaust gas are seriously carcinogenic. It belongs to the national first-class controlled emissions, which is extremely harmful to the environment and production workers.

Expand knowledge

  1. Electroplating production is mainly based on heavy metal pollution in sewage and sewage. So the country has strictly controlled the expansion of the electroplating industry and has reduced it year by year.
  2. my country’s electroplating processing is mainly chrome plating, nickel plating, zinc plating and copper plating. Among them, zinc plating accounts for 50%, and chrome plating, nickel plating and copper plating together account for 30%.
  3. If the purpose is to prevent rust, chrome plating or zinc plating is a better choice. If the focus is to prevent wear, chrome or nickel plating is a better choice.

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