How Is Chrome Plating Made?

Chrome plating can make a metal surface beautifully reflective.

Chrome plating is a common process used to make a metal surface reflective and lustrous. It is often used in the automobile and motorcycle industries, particularly with show cars or bikes. Chrome plating is the process of using chromium to coat a surface and give it a finished, reflective surface.

Chrome

Chrome wheels are actually only chrome plated over steel.

Chrome, short for chromium, is one of 91 naturally occurring chemical elements. While chrome is a metal, it is not a metal used on its own very frequently. It is nearly always coated onto another surface. Typically, chrome is applied to hardened steel, although it can be nickel, copper, stainless steel, aluminum, brass or even plastic.

Uses

Hydraulic pistons are often chrome plated to decrease wear.

Chrome is used to give metal surfaces a lustrous, reflective surface. Typically, this is for decorative purposes, but not always. A hard chrome plating (a layer of chrome thick enough to perform a hardness test, thousandths of an inch thick) is used on surfaces such as gun barrels and hydraulic pistons to increase lubricity and oil retention to decrease wear.

Application

Chrome plated materials are brightly reflective.

Chrome, whether decorative or hard plated, is always applied the same way. It is electroplated onto a surface. This is done using electric current and an electrolyte to break down the chrome into a liquid. The electric current then causes the chrome to adhere to the desired surface as the current passes through the liquid chrome.

Decorative Chrome

It is easy to see the difference a chrome surface makes.

Decorative chrome is applied in a slightly different method. First, the surface will often, but not always, be electroplated with copper and then buffed to a high sheen. Then, the surface will always be electroplated with nickel, which provides the majority of the reflectivity of the chrome. Lastly, the chrome is applied to give the surface a blue tint and a higher degree of luster, as well as protecting the surface from scratching.

Colored Chrome Plating

Chrome truly only comes in one color.

Chrome truly only has one color, and that is a slightly blue, highly reflective color. Colored chrome is, in actuality, translucent paint applied over a layer of reflective aluminum flakes. This is not actual chrome finishing, but a chrome looking paint. Black chrome, however, is possible when a contaminant is introduced into the chrome to turn it a darker color, even black.

References

• Finishing: What is Chrome?
• Finishing: Electroplating: How it Works