Relationship Tungsten Carbide Coated Tool Coating Hardness and Thickness of The Tool Wear

Tungsten carbide coated tool hardness and thickness of the coating of the tool wear plays a great influence, the higher the hardness, wear resistance is also relatively higher. However, the high hardness, crack sensitivity of the coating is also increased. The coating is too thin, can not protect the base material, the wear resistance relatively badly; thick coating, the residual stress due to the difference in thermal expansion coefficient between the coating and the substrate material is produced on a large, excessive residual stress will cause cracks produced, thereby reducing the strength of the material. Therefore, the coating thickness should be appropriate. Coating interfacial bonding force matching coat and showed good tool materials, combined with strength, long service life of the tool. Tool material and the coating material matching the better, the closer the coefficient of thermal expansion, the tool will have a high thermal conductivity and heat resistance.

Mechanical Properties of ZrN Coated Tungsten Carbide Coated Tool

ZrN, ZrN / Zr and ZrN / TiN / Zr coated tungsten carbide coated tool microhardness than the matrix YT15 tungsten carbide inserts (16.5GPa) is even higher, up to no transition layer coating hardness, 28.0 GPa, composite coating hardness is slightly lower. Under the same conditions of base material, zirconium transition layer of ZrN coating thickness maximum, minimum buffer layer of zirconium ZrN / TiN composite coating thickness. This is because during the deposition process, the titanium ions and zirconium ions collide with each other, resulting in the deposition speed is reduced, so that, in the same deposition time, the minimum coating thickness. No transition layer coating interfacial bonding force lower than that of the buffer layer coating, ZrN / TiN / Zr highest adhesion of the coating, no transition layer of ZrN coating adhesion to a minimum. This is due to take place between the transition layer of zirconium and composite coatings TiN and ZrN coatings YT15 matrix and ion diffusion, reducing the residual thermal stress between the coating and the substrate, thereby increasing the binding force of the coating.