Commonly known as metal blackening, the process is characterised by an
excellent coal black finish on iron, steel or steel alloys parts.
Usually these are instruments and small machine parts that are immersion coated.
Similar to phosphate conversion, the treatment encourages an oxide layer to form over the surface providing a protective layer. The corrosion-resistant coating is a non-metallic black iron oxide.
Cellulose lacquer, oil and waxes can be used over the coating for a more decorative and protective finishing.