Roles of rare earth oxide additives in millimeter-wave sintering of AlN
来源期刊：JOURNAL OF RARE EARTHS2008年第2期
论文作者：Yukio Makino Shoji Miyake Hiromi Nakano Takashi Yoshioka Toshiyuki Ueno
Key words：millimeter-wave; rare earth oxide; AlN,Si3N4; rapid densification; selective heating; heating rate; thermal conductivity; morphology;
Abstract: Roles of rare earth oxide (RE2O3) additives in millimeter-wave(MM) sintering of AlN were investigated from the standpoints of phase diagram, heating characteristics of rare earth oxides, and morphology of intergranular oxide phase. In the millimeter-wave sintering of AlN, densification temperature decreased with the decrease of the ionic radius of rare earth ion and was closely related with the eutectic temperature in the RE2O3-Al2O3 binary system. The lowest densification temperature in the millimeter-wave sintering of AlN with Yb2O3 additive was attributed to the largest heating rate of Yb2O3·Al2O3 binary oxide under millimeter-wave radiation. Furthermore, the lowest densification temperature could be attained while selecting the Yb2O3 content so as to form the intergranular phase with the eutectic composition in the Yb2O3-Al2O3 binary system. The result showed good agreement with the above mentioned during the sintering of Si3N4 with Yb2O3-Al2O3 additive. From TEM observation, it was verified that film-like intergranular oxide phase formed under millimeter-wave radiation was favorable for attaining high thermal conductivity in the Yb2O3 added AlNs.
Yukio Makino1，Shoji Miyake2，Hiromi Nakano3，Takashi Yoshioka4，Toshiyuki Ueno4
(1.Osaka University, 11-1 Mihogaoka, Ibaraki, Osaka 567-0047, Japan;
2.Kinki University, 3-4-1 Kowakae, Higashi-Osaka, Osaka 577-8502, Japan;
3.Ryukoku University, Seta, Otsu, Shiga, 520-2194, Japan;
4.Shimane Institute for Industrial Technology, 1 Hokuryo-cho, Matsue, Simane, 690-0816, Japan)
Abstract:Roles of rare earth oxide (RE2O3) additives in millimeter-wave(MM) sintering of AlN were investigated from the standpoints of phase diagram, heating characteristics of rare earth oxides, and morphology of intergranular oxide phase. In the millimeter-wave sintering of AlN, densification temperature decreased with the decrease of the ionic radius of rare earth ion and was closely related with the eutectic temperature in the RE2O3-Al2O3 binary system. The lowest densification temperature in the millimeter-wave sintering of AlN with Yb2O3 additive was attributed to the largest heating rate of Yb2O3·Al2O3 binary oxide under millimeter-wave radiation. Furthermore, the lowest densification temperature could be attained while selecting the Yb2O3 content so as to form the intergranular phase with the eutectic composition in the Yb2O3-Al2O3 binary system. The result showed good agreement with the above mentioned during the sintering of Si3N4 with Yb2O3-Al2O3 additive. From TEM observation, it was verified that film-like intergranular oxide phase formed under millimeter-wave radiation was favorable for attaining high thermal conductivity in the Yb2O3 added AlNs.
Key words:millimeter-wave; rare earth oxide; AlN,Si3N4; rapid densification; selective heating; heating rate; thermal conductivity; morphology;
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