Manganese phosphating is a process where a heavy deposit of manganese phosphate is applied to mainly steel and iron components either by immersion or spray. The colour of the deposit ranges from dark grey to black.
Aluminium alloys are anodised to increase corrosion resistance, to increase surface hardness, and to allow dyeing (colouring), improved lubrication, or improved adhesion for painting or other finishes.
Hard anodising is used in applications requiring increased wear resitance. It similar to decorative sulphuric anodising in that the oxide layer is produced from a sulphuric acid electrolyte (usually about 15%).
Iridite NCP was developed because of ELV, RoHS and WEEE directives to provide an alternative to chromate conversion coatings on aluminium. Iridite NCP is free of cadmium, chromium (both III &VI valency states), lead, mercury and PBB/PBDE compounds.
Zinc phosphating is a process where a fairly even crystalline coating of zinc phosphate is applied to mainly steel and iron components either by immersion or spray. The colour of the deposit ranges from a light to dark grey and can be dyed black giving a matt finish.
Alocrom is a non-electrolytic conversion coating on aluminium which is available in a clear or yellow finish.
Chemical Blacking also sometimes known as black oxide is a low cost surface treatment used on steel and stainless steel. It produces a durable, aesthetically pleasing black finish.