Mechanical Engineering - Workshop Technology - Discussion

Anodizing is an electrolytic passivation process used to increase the thickness of the natural oxide layer on the surface of metal parts. The process is called anodizing because the part to be treated forms the anode electrode of an electrical circuit.

Parkerizing, bonderizing, phosphating, or phosphatizing is a method of protecting a steel surface from corrosion and increasing its resistance to wear through the application of a chemical phosphate conversion coating.

Option B is correct.

Anodising is the process by which the natural film on aluminium is greatly increased in thickness. Aluminium metal is on the anodic side of the galvanic series. Its position is similar to zinc and magnesium, i.e it is readily oxidised.

The oxide on aluminium is naturally corrosion resistant, very hard, abrasion resistant, an insulator and very tenacious. In its natural form the oxide film on aluminium is less than 0.50 microns thick.

Explain about the galvanising, parkerising, sheradising processes.

@Lok.

Galvanising is the process of coating zinc by hot dipping.