LIU Xiaojuan , CHEN Sha'ou , SHAO Weiquan , WEI Miao , ZHANG Zhan , WANG Meiling , ZHAN Qingxue , JIA Huanjun

（College of Physics Science, Qingdao University, Qingdao Shandong 266071,China）

Abstract: The effects of the dopant Dy on the pressureless sintering and thermal-expansion behaviors of α-Al₂O₃ at constant heating rates were studied. It was showed that Dy doping promoted the densification, retarded the initial shrinking

temperature, and inhibited the particle coarsening during the sintering process of α-Al₂O₃. Moreover, the average thermal

expansion coefficients for the green compacts of undoped and Dy-doped samples were calculated to be 6.78 and 7.89×10^-6/℃ respectively, which were 7.54 and 9.98×10^-6/℃ for the sintered compacts. Therefore, it could be concluded that the influence of Dy doping on the thermal expansion coefficients of α-Al₂O₃ was unobvious, and the little change was attributed to the appearance of the Dy₃Al₅O₁₂.

Key words: Dy₂O₃ ; α-Al₂O₃ ; sintering behavior; average line expansion coefficient