ホットプレス法で作製した(Ti_>0.5<Hf_>0.5<)Cセラミックスの高温酸化

概要

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(Ti_>1-x<Hf_x) C ceramics with x=0.1, 0.2, 0.4, 0.5, 0.8 were fabricated from powder mixture of TiC and HfC by hot-pressing at 2000℃ and 32 MPa for 2 h in Ar. Oxidation of the (Ti_>0.5<Hf_>0.5<) C ceramics with the 99% relative density was performed at 1200, 1300, and 1400℃ and at Po_2=0.08 kPa. The weight gain during oxidation was monitored by an electro-microbalance and found to proceed parabolically with time. The product phases in oxide scale were identified by X-ray diffraction. A cross-sectional observation of the oxide scale was carried out by SEM to show five characteristic subscales consisting of oxycarbide ( (Ti_>0.5<Hf_>0.5<) C_>1-x<O_x) , TiO_x/C + HfO_2/C, HfO_2, HfTiO_4, and TiO_2 (called subscale Ito V, respectively). Of these scales, subscale II grew thick by the diffusion process. The oxidation of the (Ti_>0.5<Hf_>0.5<) C ceramics was discussed on the basis of the kinetic results as well as the microstructural observation.
社団法人日本セラミックス協会の論文
2002-03-01