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Effects of chemical inhomogeneities on grain growth and microstructure in Al/sub 2/O/sub 3/

Journal Article · · Journal of the American Ceramic Society; (USA)
; ;  [1]
  1. Massachusetts Inst. of Tech., Cambridge, MA (USA). Dept. of Materials Science and Engineering

The authors discuss the effects of chemical inhomogeneities and single-crystal seeds on normal and discontinuous grain growth investigated in both undoped and MgO-doped Al/sub 2/O/sub 3/. The chemical impurities in the samples were exsolved at a lower temperature than the sintering temperature and measured by SEM/EDS to determine the correlation between the distribution of impurities and the microstructure in Al/sub 2/O/sub 3/. Discontinuous grain growth was observed in regions of undoped Al/sub 2/O/sub 43/ containing the largest Ca and Si concentrations. It is suggested that doping with MgO solute reduces the effects of impurities on grain growth by increasing the bulk solubility and decreasing interfacial segregation of impurities, especially Si, and by narrowing the distribution of grain boundary-grain boundary dihedral angles.

OSTI ID:
5178683
Journal Information:
Journal of the American Ceramic Society; (USA), Journal Name: Journal of the American Ceramic Society; (USA) Vol. 72:1; ISSN 0002-7820; ISSN JACTA
Country of Publication:
United States
Language:
English