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Effect of Milling Media Purity on Pulse Electric Current Sintering and Strength of Alumina Ceramics Prepared from Transition Alumina Powder

2003; Ceramic Society of Japan; Volume: 111; Issue: 1298 Linguagem: Inglês

10.2109/jcersj.111.786

1882-1022

Yoichi Yajima, Tomohiro Yamaguchi, Seiichi Taruta, Kunio KITAJIMA,

Synthesis and properties of polymers

Alumina ceramics were densified at sintering temperatures of 1250-1550°C by pulse electric current sintering (PECS) using transition alumina powder of mixed phases of γ- and χ-alumina prepared from polyhydroxoaluminum (PHA) gel. The starting high-purity powder (HP) was obtained by grinding the alumina powder with a planetary ball mill using a high-purity alumina (purity: 99.9%) pot and balls to prevent contamination derived from the abrasion powder worn during the milling. The HP thus obtained realized full densification at sintering temperatures 50-100°C lower than those of the corresponding lower-purity powder (LP), which was obtained by grinding with a planetary ball mill using a 93%-pure alumina pot and 99.9%-pure alumina balls. The HP could also provide alumina ceramics with higher bending strengths (approximately 860MPa) than those obtained using LP.