Abstract:
Firstly, TiC
0.5N
0.5/Si
3N
4 composite ceramics were prepared by hot-pressing method using 15vol% or 25vol% TiC
0.5N
0.5 powders as conducting second phase. Then, CrAlN and TiN/Al
2O
3/TiN coatings were deposited on the surfaces of TiC
0.5N
0.5/Si
3N
4 ceramic tools by physical vapor deposition (PVD) and chemical vapor deposition (CVD) technologies, respectively. Finally, the effects of TiC
0.5N
0.5 content and coating type on tool wear characteristics were investigated by conducting continuous cutting experiments for gray cast iron on TiC
0.5N
0.5/Si
3N
4 tools, and the wear mechanisms of tools were also discussed. The results show that the increasing of TiC
0.5N
0.5 content is beneficial to enhance the matrix hardness and conductivity of TiC
0.5N
0.5/Si
3N
4 composite ceramic tools, but has little effect on wear resistance and cutting length. When depositing CrAlN coating by PVD technology, with TiC
0.5N
0.5 content increasing, the thickness, adhesion strength and hardness of coating increase, the wear performances of coated tools enhance significantly, and cutting length extends obviously. However, when depositing TiN/Al
2O
3/TiN coating by CVD technology, the variation of TiC
0.5N
0.5 content almost has no effects on coating thickness, adhesion strength and hardness, as well as the comprehensive cutting performances of TiN/Al
2O
3/TiN coated tools change little. Both of CrAlN coating and TiN/Al
2O
3/TiN coating can improve the wear resistance and cutting length of TiC
0.5N
0.5/Si
3N
4 composite ceramic tools significantly. Compared with TiN/Al
2O
3/TiN coating, CrAlN coating has higher coating hardness and adhesion strength; while TiN/Al
2O
3/TiN coated tool shows more excellent wear resistance and cutting length for TiN/Al
2O
3/TiN coating has larger coating thickness. The main wear mechanism of TiC
0.5N
0.5/Si
3N
4 composite ceramic tools is abrasive wear caused by mechanical friction, and associated with a small amount of adhesive wear.