Formation, Characterization, and Hot Isostatic Pressing of Cr2O3-Doped ZrO2 (0,3 mol% Y2O3) Prepared by Hydrazine Method |
| |
Authors: | Shingo Hirano Masaru Yoshinaka Ken Hirota Osamu Yamaguchi |
| |
Affiliation: | Department of Molecular Science and Technology, Faculty of Engineering, Doshisha University, Kyoto Tanabe 610-03, Japan |
| |
Abstract: | In the ZrO2-Cr2O3 system, metastable t -ZrO2 solid solutions containing up to 11 mol% Cr2O3 crystallize at low temperatures from amorphous materials prepared by the hydrazine method. The lattice parameter c decreases linearly from 0.5149 to 0.5077 nm with increased Cr2O3 content, whereas the lattice parameter a is a constant value ( a = 0.5077 nm) regardless of the starting composition. At higher temperatures, transformation (decomposition) of the solid solutions proceeds in the following way: t (ss)→ t (ss) + m + Cr2O3→ m + Cr2O3. Above 11 mol% Cr2O3 addition, c-ZrO2 phases are formed in the presence of Cr2O3. The t -ZrO2 solid solution powders have been characterized for particle size, shape, and surface area. They consist of very fine particles (15–30 nm) showing thin platelike morphology. Dense ZrO2(3Y)-Cr2O3 composite ceramics (~99.7% of theoretical) with an average grain size of 0.3 μm have been fabricated by hot isostatic pressing for 2 h at 1400°C and 196 MPa. Their fracture toughness increases with increased Cr2O3 content. The highest K Ic value of 9.5 MPa·;m1/2 is achieved in the composite ceramics containing 10 mol% Cr2O3. |
| |
Keywords: | |
|
|