ピストン・シリンダー型高圧装置を用いた準安定単斜晶ジルコニア高密度セラミックスの作製(<特集>極限環境)

概要

論文の詳細を見る
Single phase m-ZrO_2 ceramics (〜13mm^φ and 3-5mm^t) have been fabricated using a piston-cylinder type high-pressure apparatus under 1GPa at 1023-1173K, in which a newly developed high-pressure cell has been utilized to introduce pseudo-isostatic pressure. Starting material, meta-stable m-ZrO_2 powder prepared via a sol-gel method, was characterized by X-ray diffraction (XRD), differential thermal analysis (DTA), and transmission electron microscopy (TEM). Dense ceramics sintered at 1123K, free from macro-cracks, showed a high relative density of 〜99.5% and homogeneous microstructures consisting of fine grains (〜1μm). In-situ XRD analysis under high pressures and temperatures revealed that m-to t-ZrO_2 transition took place around 1123K under 1GPa. Mechanical properties of m-ZrO_2 ceramics have been evaluated; the maximum values of bending strength (σ_b=520MPa), Vickers hardness (H_v=9.8GPa), and fracture toughness (K_<IC>=3.9MPa・m^<1/2>) were achieved at the samples fabricated at 1123K.
2006-03-15