Naskar, Milan Kanti and Ganguli, Dibyendu (1996) Rare-earth doped zirconia fibres by sol-gel processing. Journal of Materials Science, 31 (23). pp. 6263-6267. ISSN 0022-2461

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Polycrystalline zirconia fibres, doped with 2-8 mol% of oxides of trivalent lanthanum, praseodymium, neodymium, samarium, gadolinium, and dysprosium (in decreasing cation size), were prepared by spinning of acetate-derived sols and baking the gel fibres thus obtained at 900 - 1300 degrees C for 1 h. The larger sized dopants lanthanum, praseodymium and neodymium (Group A) gave rise to tetragonal zirconia, with or without cubic zirconia, at 900 degrees C which converted partly or fully to monoclinic zirconia, in certain cases accompanied by a cubic zirconate phase at higher temperatures. The smaller sized dopants samarium, gadolinium and dysprosium (Group B) generated only tetragonal or cubic, or both polymorphs of zirconia, depending on the cation type, concentration and temperature. This `'stabilization'' of higher symmetry polymorphs with Group B dopants was associated with relatively targe crystallite size (especially when calcined at 1300 degrees C). The maximum tensile strength values of usable fibres calcined at 1300 degrees C were found to decrease with increasing size in dopant dysprosium > gadolinium > samarium > neodymium, praseodymium, tanthanum = 0). Although all the dopant cations were larger in size than Zr4+ (in the same oxygen coordination), the relative closeness in size of Group B cations with Zr4+ was considered to be the reason behind the obtained differences in properties.

Item Type: Article
Subjects: Engineering Materials
Divisions: Sol Gel
Depositing User: Bidhan Chaudhuri
Date Deposited: 30 Jul 2012 07:00
Last Modified: 05 Mar 2016 14:43

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