Mullite Whiskers Grown from Erbia-Doped Aluminum Hydroxide-Silica Gel
Mullite whiskers and anisotropic grains that were derived from erbia‐doped aluminum hydroxide–silica gel were studied. Firing 3.0‐mol%‐erbia‐doped isostatically pressed pellets at 1600°C for 1.0–8.0 h resulted in a high surface concentration of mullite whiskers. Their c‐axes were aligned preferentia...
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Published in | Journal of the American Ceramic Society Vol. 83; no. 1; pp. 60 - 64 |
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Main Authors | , , , , |
Format | Journal Article |
Language | English |
Published |
Westerville, Ohio
American Ceramics Society
01.01.2000
Wiley Subscription Services, Inc |
Subjects | |
Online Access | Get full text |
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Summary: | Mullite whiskers and anisotropic grains that were derived from erbia‐doped aluminum hydroxide–silica gel were studied. Firing 3.0‐mol%‐erbia‐doped isostatically pressed pellets at 1600°C for 1.0–8.0 h resulted in a high surface concentration of mullite whiskers. Their c‐axes were aligned preferentially along the pellet surface; the maximum length was 50 μm, and the maximum aspect ratio was 23. The pellet surface was fully covered by mullite whiskers, and small anisotropic grains with a low aspect ratio were observed in the bulk. The voids that were observed in the fracture surfaces were covered fully by mullite whiskers. The large number of voids resulted in an apparent density of 1.60 g/cm3 in the sintered pellets. The molar ratio of alumina to silica in the whiskers was in the range of 1.30–1.45 (an average value of 1.31), regardless of whether the alumina/silica powder compositions were mixed in a 3:2 or 2:1 ratio. |
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Bibliography: | istex:2CDED4F1958C2100E56134D3B96E8198F691F560 ArticleID:JACE60 ark:/67375/WNG-7FJ3361L-7 R. K. Bordia—contributing editor Supported by the Brazilian financing institutions FAPESP (through Grant Nos. 97/3062, 97/09862‐0, and 96/05714‐4) and PRONEX (through Grant No. 41/96/0935/00). Member, American Ceramic Society. ObjectType-Article-2 SourceType-Scholarly Journals-1 ObjectType-Feature-1 content type line 23 |
ISSN: | 0002-7820 1551-2916 |
DOI: | 10.1111/j.1151-2916.2000.tb01148.x |