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Preparation of Ultra‐High‐Purity Submicron Refractory Oxides
Author(s) -
MAZDIYASNI K. S.,
LYNCH C. T.,
SMITH J. S.
Publication year - 1965
Publication title -
journal of the american ceramic society
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.9
H-Index - 196
eISSN - 1551-2916
pISSN - 0002-7820
DOI - 10.1111/j.1151-2916.1965.tb14764.x
Subject(s) - hafnia , cubic zirconia , monoclinic crystal system , materials science , refractory (planetary science) , particle size , refractory metals , high pressure , mineralogy , atmospheric pressure , chemical engineering , metallurgy , analytical chemistry (journal) , ceramic , crystal structure , crystallography , chemistry , organic chemistry , oceanography , engineering physics , engineering , geology
A method was developed for preparing ultra‐ high‐purity submicron powders of refractory oxides from transition metal alkoxides. Compounds of the type M(OR) 3 and M(OR) 4 , where R is an alkyl group such as C 4 H 9 ‐, were thermally decomposed to oxides at 325° to 450°C at atmospheric pressure. Techniques were perfected to prepare, on a continuous basis, 99.95+% zirconia and hafnia with an average particle size of 100 to 200 A. The fine‐particle zirconia powder is cubic at room temperature and transforms completely to monoclinic when heated above 40O°C. The powder densifies at a considerably lower temperature than commercial spectrographic‐grade (99.9%) zirconia.