This article is about chrome electroplating for decorative or corrosion protection. There is also hard chromium plating, which is applied as a wearing surface to things like plastic injection moulds.
Chrome plate comes in several finishes: mirror finish, bright, dull, satin, pearl or black.
Substrates used are: steel, brass, stainless steel, zinc alloy (mazak) castings, brass, copper and steel are all possible and there may be others I don't know about. Plastic is slightly different, as that is vacuum deposited, rather than electroplated.
The durability does not depend upon the substrate, but upon the specifications of the plating.
Electro-plating for corrosion protection is the subject of BS EN 12540: 2000, which specifies four different service conditions:
1 - Indoors in warm, dry conditions 2 - Indoors where condensation may occur 3 - Service outdoors in temperate conditions 4 - Service outdoors in severe corrosive conditions. e.g. a marine environment.
So, although a service condition 1 plated article may well be prone to rusting or peeling in a bathroom, one plated to service condition 4 would not.
A cloth, cream cleaner & hot water remove dirt, a plastic scourer removes limescale. Avoid steel scourers, these are harder than the chrome. Avoid acids. A ball of ali foil can remove rust, and waxes can delay the rusting process for months if left alone.
Chromed pipe is not compatible with pushfit connectors. It's too hard for the teeth to bite, and joints are liable to come apart later under pressure.
Welding chromium alloys, such as stainless steel, can cause hexavalent chromium poisoning.
Plating chromium at home isn't really viable.
Disposal of liquid chromium compounds down the drain is definitely verboten.
Electro-plating for corrosion protection is the subject of BS EN 12540:2000. Now there is a spectacularly dull document ;-). It was superseded by BS EN ISO 1456:2009 apparently.