The phase constitution of a composite consisting of 12 at. pct CeO_2-3 at. pct Y_2O_3-ZrO_2/2.5 wt pct Al_2O_3 (3Y12Ce2.5Al)was determined by thermodynamic calculation. It is a combination of 36.9 at. pct cubic phase ...The phase constitution of a composite consisting of 12 at. pct CeO_2-3 at. pct Y_2O_3-ZrO_2/2.5 wt pct Al_2O_3 (3Y12Ce2.5Al)was determined by thermodynamic calculation. It is a combination of 36.9 at. pct cubic phase and 63.1 at. pct tetragonalphase at 1450℃. Green compacts were fabricated by cold isostatic pressing with powder synthesized by coating technique,and pressureless sintered at 1450℃. The fracture toughness and Vickers hardness, evaluated by the micro-indentation method,are 2.02 MPa·m^(1/2) and 11.395 GPa, respectively. The addition of 3 at. pct Y_2O_3 to 12 at. pct CeO_2-ZrO_2 ceramic leads todrastically decrease in toughness compared to composites without yttria stabilizer. No monoclinic phase is detected on thesudece of all the ground samples. The high content of cubic phase and lack of phase transformation can be attributed to thelow toughness based on the thermodynamic prediction.展开更多
基金This work is financiallv supported by the Flanders-China bilateral project(BIL 99/10 and 02/16)the Science and Technology Committee of Shanghai Municipalityand the Commission of the.European Communities in the framework of the Growth Project“BIOGRAD”(G5RD-CT2000-00354).
文摘The phase constitution of a composite consisting of 12 at. pct CeO_2-3 at. pct Y_2O_3-ZrO_2/2.5 wt pct Al_2O_3 (3Y12Ce2.5Al)was determined by thermodynamic calculation. It is a combination of 36.9 at. pct cubic phase and 63.1 at. pct tetragonalphase at 1450℃. Green compacts were fabricated by cold isostatic pressing with powder synthesized by coating technique,and pressureless sintered at 1450℃. The fracture toughness and Vickers hardness, evaluated by the micro-indentation method,are 2.02 MPa·m^(1/2) and 11.395 GPa, respectively. The addition of 3 at. pct Y_2O_3 to 12 at. pct CeO_2-ZrO_2 ceramic leads todrastically decrease in toughness compared to composites without yttria stabilizer. No monoclinic phase is detected on thesudece of all the ground samples. The high content of cubic phase and lack of phase transformation can be attributed to thelow toughness based on the thermodynamic prediction.
