Black Chromate
Zinc Black Chromate plating is an iridescent finish, that is applied to a variety of metals. Depending on the size of the piece and the surface area, the iridescent properties may be displayed, in different iridescent hues. This is considered normal when applying iridescent.
Trivalent Chromates
This chromate conversion coating is a type of coating used to passivate aluminum, zinc, cadmium, copper, silver, magnesium, and tin alloys.
It is primarily used as a corrosion inhibitor, primer, decorative finish and it can retain electrical conductivity.
The process is named after the chromate found in the chromic acid used in the bath, more commonly known as trivalent chromium.
Trivalent chromate is an iridescent conversion that can exhibit different hues. This is considered normal, when applying iridescents.
Olive Drab
Olive drab is generally designed for higher corrosion protection and rust inhibitor.
Olive drab chromate is also a iridescent chromate, that may exhibit different hues. This is considered normal, when dealing with iridescents.
Typically military or automotive applications is appropriate for olive drab plating, where exposure to corrosion is a high factor.
Passivating
The passivate process is designed to remove foreign metals and oils (usually from machining) from the surface of stainless steel. The end finish will not change the dimension of the part nor the overall appearance of the base metal. Passivation purifies the surface of a machined part and therefore improves corrosion resistance.
Wax/Lube