Effects of Underlayer (TiN, TiCN) on Transverse Rupture Strength, Bonding Strength and Cutting Tool Life of Cemented Carbide Coated with Titanium Carbide by CVD Process

화학증착(CVD)법에 의한 TiC 증착시 하부층(TiN, TiCN)이 피복 초경합금의 항절력, 접착력 및 공구수명에 미치는 영향

Generally brittle eta phase produced during TiC deposition has a bad effect on the TRS (transverse rupture strength ; thoughness). Therefore it is necessary to reduce eta(η) phase for the improvement of tool life. At this experiment some properties (TRS, bonding strength, tool life, eta phase) have been investigated by inserting TiN or TiCN underlayer between TiC layer and substrate. The results obtained were as fellows; 1. by inserting underlayer eta phase was decreased and TRS was increased, but the bonding strength was decreased. 2. the diffusion of W, Co from the substrate was hindered by the underlayer. 3. TiC layer with TiCN underlayer had the finsest gain size. 4. by inserting underlayer (TiCN or TiN) the tool life was improved and especially notch and crater wear resistance was greatly improved.