Describes the principles of phosphating products made from or coated with ferrous materials, zinc, aluminium, cadmium, and their alloys. The phosphate conversion coatings produced may serve as corrosion protection, to promote the adhesion of paints and similar materials (including plastic film), to provide lubrication during cold-forming operations such as drawing, shaping, forming, extrusion, etc., to reduce friction, or as electrical insulation.