Electroplating is a process that uses the electrolysis principle to plate a thin film of other metals or alloys onto the surface of a metal. It is a process that uses electrolysis to attach a metal film to the surface of a metal or other material to prevent metal oxidation (such as rust), improve the abrasion resistance, electrical conductivity, light reflectivity, corrosion resistance (copper sulfate, etc.), and enhance the appearance and other functions. The process is known as electroplating.

Do you know the difference between zinc plating, cadmium plating, chrome plating, and nickel plating, as well as the other common types of electroplating?

a coating of zinc

Zinc is characterized by a high resistance to color change and a moderate degree of stability in dry air. In the presence of water and a humid atmosphere, it reacts with oxygen or carbon dioxide to form oxides or alkaline zinc carbonate films, both of which have a protective effect.

Zinc can corrode in environments with high levels of acids, alkalis, and sulfides. In most cases, the zinc-plated layer is given a passivation treatment. Following treatment in chromic acid or chromate solution, the passivation film that is formed is less likely to interact with moist air, which results in a significant increase in the material's resistance to corrosion. Hydrogen removal is a process that must be carried out on steel parts that have high mechanical strength requirements as well as spring parts, thin-walled parts (wall thickness 0.5m), and other similar components. Components made of copper and copper alloys do not need to have hydrogen removed from them.

Zinc plating is advantageous in terms of price, ease of processing, and final product quality. Because the standard potential of zinc is fairly negative, zinc plating can be anodized for a wide variety of metals.

Zinc plating finds widespread application in a variety of settings, including those with favorable atmospheric conditions. But not suitable for friction parts.

plating with cadmium

Features: The cadmium coating is relatively stable, has a strong resistance to corrosion, provides good lubricity, dissolves very slowly in dilute hydrochloric acid, but dissolves very easily in nitric acid; it is insoluble in alkali; and its oxides do not dissolve in water. Components that come into contact with the marine atmosphere or seawater and hot water above 70 degrees Celsius are ideal candidates for this coating.

Under certain electrolytic conditions, the cadmium coating that is obtained is more beautiful than the zinc coating that was previously obtained. This is because the cadmium coating is softer than the zinc coating, the coating has less hydrogen embrittlement, and it has strong adhesion. However, the cadmium gas that is produced when cadmium is melted is toxic, as is the soluble cadmium salt.

Cadmium acts as a cathodic coating for steel in environments with typical conditions, but it acts as an anodic coating in environments with high temperatures and in marine environments.

Application: Its primary use is to protect components from the corrosion caused by seawater or other similar salt solutions as well as the environment. Cadmium plating can be found on a variety of components used in the aviation, marine, and electronic industries, including springs and threaded parts. It is possible to polish and phosphate the material, but it should not be used for tableware.

a coating of chrome

Characteristics: Chromium is highly resistant to the effects of a humid environment, alkali, nitric acid, sulfide, carbonate solution, and organic acid. Additionally, chromium is easily soluble in both hot concentrated sulfuric acid and hydrochloric acid. If the chromium layer is put to use as an anode while being subjected to the force of direct current, it readily dissolves in a solution of caustic soda. The chromium layer possesses excellent adhesion, high hardness, 800–1000V, good abrasion resistance, strong light reflectivity, and high heat resistance, among other desirable characteristics. It does not change color below 480 degrees Celsius, but it starts to oxidize above 500 degrees Celsius, and its hardness significantly decreases at 700 degrees Celsius. The drawbacks of chromium include the properties of being hard, brittle, easily broken, and porous.

The potential of chromium can be altered through the process of passivation, which occurs naturally in the atmosphere and results in the formation of a passivation film. Chromium applied to iron results in the formation of a cathodic coating.