Si-TiC-TiO_2混合粉末より作製したSi_3N_4-TiN複合セラミックスの微構造と機械的特性

概要

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Microstructure and mechanical properties of the self-composed Si_3N_4-TiN ceramics prepared from Si, TiC and TiO_2 mixed powder compacts were studied. Si_3N_4 matrix and TiN particles were formed during the sintering process of the ceramics. The results were compared with the reaction bonded Si_3N_4-TiN ceramics prepared from Si and TiN mixed powder compacts. The TiN particles in the self-composed Si_3N_4-TiN ceramics were finely and homogeneously distributed in comparison with those in the reaction bonded Si_3N_4-TiN ceramics. The fracture toughness was 5.0 MPa・m^<1/2> in Si_3N_4 ceramics, which incresed with addition of TiN particles. Fracture toughness of 6.3 and 5.9 MPa・m^<1/2> were obtained at 20 vol% TiN for the self-composed Si_3N_4-TiN ceramics and the reaction bonded Si_3N_4-TiN ceramics, respectively. The incresed fracture toughness is probably due to the thermal expansion coefficient difference between the Si_3N_4 and TiN. The fracture strength was 930 MPa in Si_3N_4 ceramics and it was retained up to 20 vol% TiN in the self-composed Si_3N_4-TiN ceramics, whereas in the reaction bonded Si_3N_4-TiN ceramics the fracture strength was 350 MPa at 20 vol% TiN, only 40% of the initial value. This is possibly attributed to the difference in the distribution of TiN particles between two-ceramics.
社団法人日本セラミックス協会の論文
1997-09-01