| Chrome rims and other chrome parts are often used | | | | protection. This kind of process is used for auto parts, |
| to improve the appearance of vehicles. The bright | | | | jewelry, hardware, hand tools and appliances. |
| decorative finish of chrome plating is very familiar and | | | | Black Chrome |
| enhances the appearance as no other method of | | | | For black chrome an underlying base of metal is plated |
| customising your ride can. Chrome plating is used on | | | | with bright or mate nickel then the chromium plating |
| exhausts, handles, mirrors and trims as well as on the | | | | applied over this. Black chrome is not as hard as bright |
| very popular chrome rims. Chrome plating is not just | | | | chrome and not so long lasting. It is often oiled or |
| used for decoration however. The protective coating | | | | waxed to improve the appearance. Black chrome is |
| of the chrome makes the technique of chrome plating | | | | used in some auto parts, solar panels and some gun |
| useful for other applications. Chrome plating can be | | | | sights and other optical components. |
| used to protect pistons and other engine parts. | | | | Hard Chrome |
| Chrome plating consists of applying a thin layer of | | | | Unlike the other types hard chrome is not used to give |
| chromium on to an iron, copper or other base metal to | | | | a decorative finish but to give a very long lasting |
| give a protective and decorative finish. Chromium itself | | | | protective coating for pistons, hydraulic rods, cylinders |
| is a reactive metal that reacts readily with the oxygen | | | | and other engine parts. The chrome is plated more |
| in the air. Unlike iron which forms a very unstable oxide | | | | thickly than for the decorative finishes to make a |
| that flakes and falls apart chromium oxide is hard and | | | | strong protective layer. |
| stable and forms a protective layer which prevents | | | | The Electroplating Procedure |
| the underlying metal from corroding. | | | | Before the object can be plated it must be cleaned |
| Different electroplating techniques are used to produce | | | | thoroughly by degreasing the cleaning manually to |
| different effects. The shiny highly decorative finish that | | | | remove any debris and impurities. Sulphuric acid or |
| we are all familiar with on chrome rims and other auto | | | | other strong acids are also used. Other pre-treatments |
| parts is known as bright chrome. Other variations are | | | | may also be used. Once cleaned the object is |
| black chrome and hard chrome. | | | | suspended in the plating solution. For bright chrome a |
| Bright chrome is used when a decorative finish is | | | | solution of sulphuric acid and chromic acid is used and |
| required, on car rims for instance, and is applied fairly | | | | for black chrome, chromic acid with acetic acid and |
| thinly. Decorative chrome is applied after a nickel | | | | barium acetate. The temperature of the bath must be |
| coating is plated to a base of steel, copper alloys, steel | | | | kept within 45C to 50C for bright chrome and 32C to |
| and aluminum alloys and plastic. The nickel provides the | | | | 46C for black chrome. The thickness of the plating is |
| luster and the chrome provides the hardness and | | | | controlled by the current used. |