TiC/SiCウイスカー複合セラミックスの作製及びその特性

概要

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TiC/SiC whisker composites were fabricated by the hot-press method. As a sintering additive, 10 wt% Cr_7C_3 was added and dense sintered bodies were obtained by 1600℃-1h hot-pressing. Mechanical properties of the sintered bodies were influenced by the grain size and the dispersion of the sintering additive. For a grain; size of Cr_7C_3 of 3.53μm, flexural strength (σ_f) and K_IC had maximum values of 660 MPa (V_f=10%, hot-pressed at 1600℃ for 1h) and 5.2 MPa√<m> at V_f=30%,hot-pressed at 1750℃ for 1h) , respectively. On the other hand, when hot-pressed at 1900℃ for 1h. 5h without any sintering additive,σ_f and K_<IC> were 690 MPa and 6 MPa MPa√<m> at V_f of 10%, respectively. In the 1900℃-sintered specimens the whiskers and surrounding matrix were ripped off together from the fractured surface, indicating that the crack bowing and deflection have occurred. Such behavior was not found in the specimens containing a sintering additive, and their whiskers were fractured at the same plane as the matrix fracture surface. This is the reason that 1900℃-1.5h hot-pressed specimens without sintering additive had higher K_<IC> than that with sintering additive. The different fractured surfaces are probably dependent on the residual thermal stress conditions caused by the difference in hot-pressing temperature or by the presence of Cr_7C_3 in the matrix/whisker interface.
社団法人日本セラミックス協会の論文
1990-10-01