高強度ZrO2-Al2O3複合体の微細構造

概要

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ZrO2-Al2O3 composites with the bending strength of 3000MPa were developed. To discuss the mechanism which gives such a high bending strength, microstractures and atomic diffusions of incoherent ZrO2-Al2O3 interfaces in the composite of ZrO2-2 mol% Y2O3 with Al2O3 addition of 20 wt% were investigated using high resolution analytical electron microscopy. The results obtained are summarized as follows. (1) In the composite Al2O3 grains were dispersed uniformly in ZrO2 matrix and no crack and no flaw were observed. (2) In many ZrO2 grains dislocations were brought about by tensile stress in ZrO2 grains generated by the thermal expansion mismatch between ZrO2 and Al2O3. They contributed to the division of tetragonal ZrO2 grain and the relaxation of residual tensile stress in ZrO2 grain. (3) ZrO2 and Al2O3 grains formed direct interfaces without any reacting phases. (4) At ZrO2-Al2O3 grain interfaces, the diffusions of Zr and Al to Al2O3 and ZrO2 grains were observed respectively. It was considered that these chemical effects strengthened ZrO2-Al2O3 grain interfaces.
社団法人粉体粉末冶金協会の論文