Chrome is applied to materials almost exclusively through the electroplating process. Electroplating is a deposition process achieved when a negative charge is put on a base material. The base is immersed in a solution containing a metal salt. The positively charged ions of this solution are attracted to the base causing a plate to form and bond evenly on the surface of the base.
Chromium is a very strong, durable and hard metal. Chrome plating offers a very high resistance to corrosion. This metal is one of the hardest metals available. It offers an 8.5 hardness rating (out of 10 high) on the Mohs scale for material hardness. Chrome can easily scratch any material with a lower Mohs hardness rating. At room temperature, chromium's density is 7.19 grams per cubic-centimeter. The melting point of chromium is 3,464.6 degrees Fahrenheit while its boiling point is 4,838 degrees Fahrenheit. Chromium is silver to gray in appearance. This metal can take a high polish.
Decorative chrome plating is very popular. Decorative chrome plating is typically applied in very thin layers ranging in thickness from 0.002 mm to 0.020 mm. Even a very thin layer of chrome offers increased durability to a work piece. Decorative chrome plating is often applied over nickel, which itself is often applied on a steel, aluminum, plastic or copper base. This type of plating is ideal for hand tools, automotive trim, jewelry and appliances.
Hard chrome plating is more suited for objects that receive a lot of regular wear and tear. Hard chrome plating is also referred to as functional chromium plating. This type of chrome plating is applied in thicknesses ranging from 0.10 mm to 10.0 mm depending on the application. Manufacturers apply hard chrome plating to many objects such as crankshafts, printing plates, hydraulic cylinders, hydraulic rods and pistons for engines. Cutting tools and molds for fiberglass parts often feature hard chrome plating.