放電表面改質膜の結晶構造に関する研究

概要

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This study deals with the microstructure of TiC hard layer which is produced by electrical discharge machining with semi-sintered electrode. This technology were developed to improve the wear proof of cutting tools, molds and dies mainly at the first. But, it was observed that the wear of cutting tools with TiC hard layer by EDM is more shorter than PVD or CVD coated tools under high-loaded cutting conditions. Therefore, there is some limitation to apply to cutting tools in full range. In this reports, some experiment is done to be cleared above mentioned problem by means of characterizing the microstructure of TiC by EDM. The main result of experiments are as follows ; (1) The microstructure of hard layer made with semi-sintered electrode exhibits extremely amorphous characteristics with lattice constant a=4.3062Å, (2) Comparing with molecure ratio 1: 1 of TiC, piled TiC atomic composition. shows TiC_<0.45>. Carbon composition is extremely reduced. Therefore, It is thought that TiC is deposited on the substrate breaking down atomic distribution of electrode. (3) Above mentioned microstructure and grain morphologies were caused by ultra high cooling velocity in discharged crater on substrate. (4) As compared with the TiN coated carbide square end mill tool, EDC tool does not result in a precise coated layer like a CVD or a PVD coated layer, which tends to be relatively shorten in tool life.
社団法人精密工学会の論文
2003-05-05