What is the main objective of Parkerizing?

Explanation:

Parkerizing: 

• It is a process of applying an anti-corrosion and lubricating phosphatized surface treatment.
• Parkerizing is an electrochemical process that creates a protective iron-phosphate layer on the outer surface of steel.
• 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.
• Parkerizing is usually considered to be an improved zinc or manganese phosphating process.
• Parkerizing is commonly used on firearms as a more effective alternative to protect against rust.
• It is also used extensively on automobiles to protect unfinished metal parts from corrosion.
• The Parkerizing process cannot be used on non-ferrous metals such as aluminium, brass, or copper.
• It similarly cannot be applied to steels containing a large amount of nickel, or on stainless steel.