Kiyono, Hajime , Miyake, Yuho , Nihei, Yusuke , Tumura, Tomoki , Shimada, Shiro
Journal of the European Ceramic Society, 32(7): 1413-1417
Faculty of Engineering, Hokkaido University, Kita-ku, Sapporo, 060-8628, Japan
Faculty of Engineering, Oita University, Dannoharu, Oita, 870-1192, JapanÂ
AbstractÂ
A Si3N4 composite containing needle-like TiN particles (7 vol%) was fabricated. Needle-like TiN particles several micrometers long were synthesized using NH3 nitridation of TiO2 nanofiber, which was obtained using hydrothermal treatment. A mixed powder of a-Si3N4 and the needle-like TiN particles with additives was hot pressed at 24 MPa and 1850 °C for 1 h in N2 atmosphere. Mechanical properties of the composite were compared with those of a composite containing rounded TiN particles and a monolithic b-Si3N4 ceramic. The Si3N4 matrix of the composites containing TiN was mainly a-phase, suggesting that the a-b phase transformation of Si3N4 was inhibited by the presence of TiN. Although fracture strength of the composites was lower, fracture toughness was comparable to that of monolithic b-Si3N4 ceramics. Hardness of the composites was about 19 GPa and was greater than that of the monolithic b-Si3N4 ceramic.
