正方晶安定化ジルコニアの水蒸気雰囲気アニールでの相転移(<小特集>セラミック材料)

概要

論文の詳細を見る
Changes in the crystalline phase and microstructure on the surface resulting from low-temperature annealing of tetragonal zirconia polycrystals doped 2, 3 and 4 mol%Y_20_3 Were investigated under humidity controlled conditions at 0〜7.35 kPa of water vapor pressure and 100〜600℃ for l〜50 hr. The tetragonal phase Zr02 transformed to the monoclinic structure by annealing at low temperature conditions such as 100〜500℃. The phase transformation caused mlcrocracks on the surface and resulted in significant loss of fracture strength. The critical temperatures of the phase transformation of ZrO_2-2mol%Y_2O_3, ZrO_2-3 mol%Y_2O_3 and ZrO_2-4mol%Y_2O_3 Were 500, 400 and 350℃, respectively. The phase transformation proceeded rapidly on the surface but quite slowly inside the body. The rate of the phase transformation on the surface was first order with respect to the concentration of the tetragonal ZrO_2 and increased with increasing water vapor pressure by Langmuir type relation. The aearent activation energy of the phase transformation was about 85 kJ/mol.
社団法人日本材料学会の論文
1987-01-15