Zinc
Give galvanic protection to noninvaluable metals. Untreated (the Zinc of the TYPE I) does not maintain luminous surface for a very long period.

The Zinc of  TYPE II and III delay the formation of the white products of corrosion on plated surface. The lifespan of the zinc electro deposit is in function of the conditions such as the thickness, the exposure, and the use.

Black oxide
Weak Resistance to abrasion. Low resistance to corrosion except for the stainless steels of series 300 with treatment of CLASS 4. Used when a black surface and a low reflexion of the light are required.

Cadmium
Electrodeposition most generally used. Excellent corrosion resistance.

Anodize
Not to be applied on assemblies or part with joints or cavities which could lock up the solution. Good electric barrier and good base of painting. Can be dyed in all the colors.

Nickel
There is a nickel finish for almost any need. Nickel can be deposited in a soft form or hard, matt or luminous. The corrosion resistance is related to the thickness applied. Low thermal dilation. Slightly magnetic.

Tin
Matt or luminous aspect must be indicated. A nickel or copper underlayer must be employed on zinc and brass alloys. Very good Hardness and good corrosion resistance.

Passivation
Dissolves all the traces of foreign metals such as iron particles, residues of tool, pieces, etc, which will cause spots of rust if they are not removed. A thin film and transparent formed above surface, prevents these conditions of occurring.