초경절삭공구의 CVD Diamond 코팅층 형성에 관한 연구

A Study on the Creation of CVD Coating Layer for the WC-Based Cutting Tool

CVD diamond films was deposited on hard tool substrate by MPECVD(Microwave Plasma Enhanced Chemical Vapor Deposition) System. Etchingwith diluted HNO3 and Murakami s reagent were used as substrate pretreatment. CVD diamond thin films were deposied by normal and cyclic process, which can be carried out periodically on and off the methane and oxygen gas flow in the H2-CH4-O2 system. Crystal structures for grown films, such as microcrystalline and surface morphology are characterized in term of growth condition by SEM, micro raman spectroscopy and AFM respectively. The Raman spectra of the nano particle consist mainly of two clearly distinct peak near 1140 and 1332cm-1. The Ra surface roughness of the films was observed at below approximately 200nm. The best conditions of CVD coating for hard insert tool are microwavepower 1000W, pressure 30torr, CH4/H2 rate 2% and deposition time 4hr. Also, CVD diamond coating has carried out on the surface of hard-metal inserts turning tool using microwave plasma CVD device. Through the pre-treatment process in coating and the gas flow control it forms optimal diamond coating layer condition on insert tool surface.