**6.2 Wear mechanism in difficult-to-machine materials with diamond tool**

When it comes to cutting difficult to machine materials with diamond tool, ferrous materials are first among several. Diamond turned ferrous materials are generally used


#### **Table 5.**

*Wear patterns and mechanisms in difficult to machine materials [18].*

as precision dies and molds. The other class of materials are glass, crystal materials like silicon, silicon carbide, germanium, selenide, and zinc sulfide. Rapid tool wear rate limits the diamond turning applications in machining of difficult to machine materials. In machining ferrous metals for high precise and complex surfaces, diamond tools are subject to catastrophic wear, which subsequently downgrades surface quality. The diamond tool wear rate is very high in case of machining ferrous materials and it is 10,000 times higher than that in case of machining brass [19].

In difficult to machine materials, the wear pattern is flank wear assisted with micro/nano grooves. Initially the microchipping is also observed. In Difficult to machine materials dominant wear mechanism is chemical wear based on the interface temperature. The interface temperature decides the type of wear mechanism which is predominantly categorized into diffusion, graphitization and oxidation. **Table 5** shows the wear pattern and wear mechanisms for difficult to machine materials in diamond turning.
