Partially stabilized zirconia refractory

Abstract

Abstract Body consisting essentially of ZrO2 and CaO with CaO being 2-5 wt. percent of the body. Microstructure consists essentially of cubic grains collectively constituting volumetrically the major phase, smaller primary monoclinic zirconia grains randomly dispersed substantially at grain boundaries between adjacent cubic grains, and, as a principal new feature effecting increased strength and elasticity properties, extremely finely divided precipitate of monoclinic zirconia dispersed intragrangularly throughout the cubic grains and being substantially smaller than the primary monoclinic zirconia grains. Cubic grains composed essentially of a solid solution of ZrO2 in a compound CaZr4O9. Manufacturing process comprises preparing batch material of prescribed composition, heating the material at firing temperature of at least 1,800* C. that causes sintering or melting of the material, cooling fired material to an annealing temperature of 900*-1,700* C. and maintaining it at the annealing temperature for at least about one day and thereafter continuing cooling of the material. Product is either sintered or fusioncast body. Batch material can be either unfused or fused finely divided particles. Unfused batch can be either unreacted or prereacted raw materials. For optimum density from unreacted raw material batch, it is heated, prior to molding, to prefiring temperature of 900*-1,300* C. for at least about one day. CaO can be provided in batch by heat decomposable compound whose solid decomposition product is substantially all CaO, e.g. calcium acetate monohydrate.

Inventors

• 👤 Ronald C Garvie

Bibliographic Details