Effects of transient thermal shock loadings on the structure of zirconia ceramics

Abstract

In this paper the influence of thermal shock loadings on the phase composition and microstructure of ZrO[2](Y[2]O[3]) and ZrO[2](MgO) ceramics was studied. It was found that thermal shock strains were no effect on phase composition of ZrO[2](Y[2]O[3]) ceramics. Reducing the concentration of high-temperature tetragonal t-ZrO[2] and cubic c-ZrO[2] modifications and rising the content of low-temperature monoclinic m-ZrO[2] crystal system with increasing the number of thermal shock strains were observed. The values of region coherent X-ray scattering of ZrO[2](Y[2]O[3]) ceramics didn't changed, while the crystallite size of ZrO[2](MgO) ceramics decreased. The formation of block structure in all studied ceramics was observed, the sizes of the blocks formed in the ZrO[2](Y[2]O[3]) and ZrO[2](MgO) ceramics were slightly different. The formation of the blocks in ZrO[2](Y[2]O[3]) ceramics occurred on the grain boundaries, while the crystallites in ZrO[2](MgO) ceramics were crushed due to phase transformation.