Hard Chrome Plating

The chrome plating process has many applications in the manufacturing, production and consumer goods industries. Commonly known as just "chrome," chrome plating provides a protective coating and shiny luster when applied to metal parts and products. Chrome plating can have decorative purposes or can enhance the desirable properties of machine components.

Hard chrome plating is an electroplating process in which chromium is deposited from a chromic acid solution. Thickness of hard chrome plating ranges from 2 to 250µm. Various types of hard chrome include micro-cracked chromium, micro-porous chromium, porous chromium and crack free chromium. It is essential that the micro-cracked and porous coatings have a minimum thickness between 80-120µm in order to confer adequate corrosion resistance. Micro-cracked chromium has a Vickers hardness of 800-1000 kg/mm2, while crack-free chromium has Vickers hardness between 425-700 kg/mm2. The formation of micro-porous chromium is achieved by a specialised plating method involving the use of inert suspended particles. Porous chrome plating is developed by etching electrodeposited chromium. These are designed to retain lubricant, for sliding and bearing type applications.

Chrome plating is used for wear and corrosion resistance in addition to its tribological (low friction) characteristics. However, there are environmental concerns associated with disposal of the plating solution. This has led to many users of chrome plating seeking alternative coating methods. One option is to replace hard chrome with high velocity oxy-fuel (HVOF) sprayed coatings of cermet materials such as WC/Co (Tungsten Carbide/Cobalt). 

What Is Hard Chrome Plating Used For?

A variety of industrial applications use hard chrome plating to increase the wear and corrosion resistance of equipment components. Also known as engineered chrome or industrial chrome, hard chrome plating reduces friction between machine parts and improves component durability. A hard chrome coating extends the lifespan of machine components and reduces maintenance downtime and expenses.

Hard chrome plating can also be useful in repairing damaged, worn or mis-machined parts. A component that is too small or has become worn down can benefit from applying a thick coating of hard chrome plating to return it to the correct dimensions. Stripping the damaged plating through a chemical process and applying new hard chrome plating can repair a damaged part.