1993 Fiscal Year Final Research Report Summary
Characteristics of Ceris-Doped Tetragonal Zirconia Powders Prepared Using Alcohol as a Crystallization Solvent
| Project/Area Number |
04650690
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| Research Category |
Grant-in-Aid for General Scientific Research (C)
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| Allocation Type | Single-year Grants |
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| Research Field |
無機工業化学・無機材料工学
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| Research Institution | Tohoku University |
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Principal Investigator |
SATO Tsugio Tohoku University, Faculty of Engineering, Associate Professor, 工学部, 助教授 (90091694)
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| Co-Investigator(Kenkyū-buntansha) |
OKUWAKI Akitsugu Tohoku Univ. Fac. Eng., Professor, 工学部, 教授 (70005320)
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| Project Period (FY) |
1992 – 1993
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| Keywords | CeO_2-ZrO_2 / Supercritical methanol / Supercritical drying / crystallization / Agglomeration / Sintering / Fracture / Organic solvent |
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| Research Abstract |
In oder to improve the sinterbility and mechanical properties of ceria-doped tetragonal zirconia, amorphus CeO_2-ZrO_2 gels prepared by coprecipitation in ammonia solutions were crystallized and dried using supercritical methanol. The onset of crystallization of the gels, from calcining in air was 420^oC, while 200^oC to 250^oC in the presence of water and organic solvents such as methanol. The sintering behavious of CeO_2-ZrO_2 powders were sensitive to the crystallizing conditions, since hard agglomerates formed when the precipitated gels were crystallized by normal calcination in air, wheras soft agglomerates formed when they were crystallized in water and organic solvent. CeO_2-ZrO_2 powders crystallized in methanol and water at 250^oC were sintered to full theoretical density at 1150^oC and 1400^oC, respectively, whereas that crystallized by calcination in air at 450^oC was sintered to only 95.2% of theoretical density, even at 1500^oC.Fracture strengths of CeO_2-ZrO_2 fabricated using the powders crystallized in methanol were much higher than those crystallized in water and air and increased with supercritical drying and/or dispersing oxide particles such as MnO, Al_2O_3 and CeMnAl_<11>O_<19> at the grain boundary of ZrO_2.
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