| Summary: | 碩士 === 國立臺灣大學 === 化學工程學研究所 === 88 === This paper principally discuss how the surface hydroxyls removed by HDMS treatment or not influece the ZrO2 powders.For the powders without HDMS treatment the content of t-ZrO2 was found to decrease with increasing calcination time and temperature. Nevertheless, for the powders with removing surface hydroxyls by HDMS treatment, either pure or with yttrium-doping, only the t-ZrO2 was produced throughout the entire calcination temperature from 300 to 1100 oC and the average crystallite size of t-ZrO2 was merely 6.5nm after calcination up to 900 oC. In addition, the specific surface area of powders with HDMS treatment was larger than those without HDMS treatment. These make it possible to test the reversibility by, after the cold work, carrying out thermal treatment at sufficiently high temperatures while maintaining the crystallite not exceeding the "critical size".
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