확산접합을 이용한 초소형 PCD 드릴 공구 블랭크 제작에 관한 연구

Abstract

In this study, a precision machining drill blank, consisting of a micro polycrystalline diamond-tungsten carbide (PCD-WC) composite tip and a cemented carbide (WC-Co alloy) shank, was fabricated via diffusion bonding. Two types of filler metal (sheet and paste-type) were used in the copula region. The two base metals of the WC-Co alloy, along with a nickel alloy filler metal at the interface, were pressed together at high temperature and pressure for a period of time sufficient for atomic diffusion. The copula (bonding layer) of the internal bond was examined using optical microscopy and scanning electron microscopy. The bond characteristics and bond interface composition for the diffusion bonded blank, not accessible by conventional nondestructive measurement techniques, were evaluated using micro X-ray computed tomography. A universal testing machine was used to determine the strength of the bonded proportional specimen on cemented carbide. This fabrication technique and the evaluation procedure for the bond interface provide the means to predict the effects of diffusion bonding for micro PCD drill blank fabrication.