Accession Number : AD0877613

Title :   High Purity Fine Particulate Stabilized Zirconia (Zyttrite).

Descriptive Note : Final technical rept. 1 Jun 67-17 Jun 70,

Corporate Author : AVCO CORP LOWELL MA SYSTEMS DIV

Personal Author(s) : Rhodes, William H. ; Haag, Robert M.

Report Date : SEP 1970

Pagination or Media Count : 201

Abstract : Sintering and hot pressing process studies were conducted on 100 A particle diameter 6 1/2 mole percent Y2O3 stabilized ZrO2 powder produced by an organometallic route. Powder characteristics to include particle size, agglomerate size, agglomerate bonding and chemistry were correlated with processing behavior and used as a guide in achieving 99 percent dense fabricated shapes with grain sizes between 5 and 20 microns for sintered bodies and 0.4 and 7 microns for hot pressed shapes. Sintering temperature was 600C lower than that required for commercial 2 micrometer single phase stabilized zirconia powder because of the good solid solution dispersion and high powder activity. Low pressure (5 Kpsi) hot pressing was performed 140C lower than sintering. Intermediate pressure (< 30 Kpsi) and high pressure (> 100 Kpsi < 200 Kpsi) hot pressing processes were investigated. Purity was maintained in sintering; however, from 40 to 600 ppm carbon was introduced during hot pressing which was reduced to between 10 and 300 ppm during annealing. Several samples possessed second phase inclusions such as monoclinic ZrO2 or ZrSiO4 but, in general, single phase structures were produced. The powder surface chemistry, inter-agglomerate bonding and agglomerate size were extremely important variables in governing the production of uniform sintered microstructures. Best results were achieved with alcohol washed powder. (Author)

Descriptors :   (*ZIRCONIUM OXIDES, STABILIZATION), SINTERING, HOT PRESSING, POWDERS, MICROSTRUCTURE.

Subject Categories : Ceramics, Refractories and Glass

Distribution Statement : APPROVED FOR PUBLIC RELEASE