Difference between nickel plating, chrome plating and zinc plating
Electroplating is the process of applying a thin layer of metal or alloy to some metal surface using the principle of electrolysis. This thin layer prevents oxidation of metal parts, improves wear resistance, electrical conductivity, reflectivity, corrosion resistance (copper sulfate, etc.), and aesthetics of the parts.
Common plating is divided into specific processes such as copper plating, gold plating, silver plating, chromium plating, nickel plating, and zinc plating. Among them, galvanizing, nickel plating and chrome plating are the most widely used in the manufacturing field, so what is the difference between the three?
Chrome Plating
Chromium is a bright white metal with a slight blue tint. Plating a layer of chromium on a metallic or non-metallic item by electrolytic or chemical methods is called chromium plating.
Chromium is very stable in humid environment, alkali, nitric acid, sulfide, carbonate solution, organic acid, and easily dissolves in hydrochloric acid and concentrated sulfuric acid.
Nickel Plating
The method of electroplating nickel or nickel layer by electrolytic or chemical method is called nickel plating.
Nickel is chemically stable in atmospheric and alkaline solutions and its color does not change easily. Although it oxidizes only at temperatures above 600°C, it dissolves slowly in sulfuric and hydrochloric acids and readily in dilute nitric acid. Good corrosion resistance, easily passivated in concentrated nitric acid.
Nickel coating has high hardness, simple polishing, and high aesthetics such as reflecting light. The disadvantage is porosity. To overcome this disadvantage, multi-layer metal coatings can be used, with nickel as an intermediate layer.
Conventional nickel plating is electroplated nickel and chemical nickel plating, according to the way of plating there are hanging nickel plating, rolled nickel plating.
Electroplated nickel is available in bright nickel, matte nickel, semi-gloss nickel, matte nickel, and various alloy nickel by decorative effect.
Electroless nickel plating is a method of chemically coating a metal or non-metal surface with a layer of nickel. Electroplating, also known as autocatalytic plating or electrode-free plating, is a new surface treatment process that uses the principle of autocatalysis to deposit alloys on the surface of a substrate, unlike traditional plating that requires the use of an external power source.
Galvanization
Zinc plating plays a role in aesthetics and rust prevention, with reference to surface treatment techniques, by applying a zinc layer to the surface of a metal, alloy or other material.
Zinc is relatively stable in dry air and does not change color easily. In water and humid environments, it reacts with oxygen or carbon dioxide to form zinc oxide or alkaline zinc carbonate films, which prevent zinc from oxidizing and provide protection.
Zinc is susceptible to corrosion in acids, alkalis, and sulfides. In general, zinc coatings must be passivated. After passivation in chromic acid or chromate solution, corrosion resistance is greatly enhanced because the passivated film formed is difficult to interact with moist air. In spring parts, thin-walled parts (wall thickness < 0.5 m), and steels with high mechanical strength, hydrogen is sometimes removed without removing copper or copper alloy parts.
The most basic differences between the three types of plating
1: Chromium plating mainly improves surface hardness, aesthetics and rust resistance. Chrome coating has good chemical stability. It is suitable for alkalis, sulfides, nitric acid and most organic acids, but dissolves in hydrohalogen acids (such as hydrochloric acid) and hot sulfuric acid.
2: Nickel plating is mainly wear-resistant, corrosion-resistant and rust-proof, and is generally thin.
3: Galvanizing is mainly beautiful and rust proof. Zinc is a reactive metal that reacts with acids, has poor corrosion resistance, and is the cheapest of the three.
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