TiC-SiC硬質セラミックスの合成と機械的性質

Abstract

TiC-SiC ceramics were sintered at 1600–1800 °C using a resistance-heated hot pressing machine. No phase except TiC and α-SiC was detected after sintering. Dense ceramics were obtained in the range of 0–70 mol% SiC at a sintering temperature of 1800 °C. The Young’s moduli for dense TiC-SiC ceramics ranged from 426–457 GPa, regardless of the SiC additive amount. The addition of SiC above 10 mol% increased Vickers hardness by 2–3 GPa. The addition of SiC above 10 mol% inhibited the grain growth of TiC, and brought fine equiaxed granular structure to sintered bodies. The addition of SiC increased fracture toughness in the conditions 0–50 mol% SiC at 1800 °C, 0–20 mol% SiC at 1700 °C, and 0–10 mol% SiC at 1600 °C. The highest fracture toughness value 6.5 MPa m1/2 was obtained for the TiC-50 mol% SiC ceramic sintered at 1800 °C. The addition of SiC greatly increased thermal conductivity from 27 W m−1 K−1 for pure TiC to 98 W m−1 K−1 at 70 mol% SiC.