Coating is the technique of placing hard material around a base metal.
In 1969, technology to coat cemented carbide with hard materials several micrometer thick for use as a cutting tool material was developed. When the technology was first introduced the first coating was in the form of a titanium carbide (TiC) coated grade. Since then, TiC coating technology has become known for its excellent performance and TiC coated grade became widely used for many applications.
There are two kinds of coating methods, chemical vapour deposition (CVD) and physical vapour deposition (PVD).
Coating materials include TiC, TiN, titanium carbo-nitride (TiCN) and aluminium oxide (Al2O3). The hardness of coating layers ranges from 2,000HV-3,000HV in Vickers hardness.