HIGHLY HYDROPHILIC, LOW FRICTION CERAMIC MATERIAL

摘要

PROBLEM TO BE SOLVED: To obtain a ceramic material excellent in mechanical strength, durability and friction characteristics in the presence of water by uniformly dispersing acicular and/or platy multiple oxide grains (A) essentially contg. Zn and Al and multiple oxide grains (B) having a spinel type crystal structure of ZnAl2 O4 in a matrix phase of α-alumina. SOLUTION: The average ratio of ZnO:Al2 O3 in the grains A is 1: >=3 when Zn and Al are expressed in terms of oxides and the aspect ratio of the acicular grains is >=3. The amt. of the grains B in the ceramic material is 30 wt.%. The objective ceramic material is obtd. by forming a compact of a prescribed shape from a mixture of α-alumina powder as principal starting material, acicular multiple oxide powder of ZnO.nAl2 O3 and a small amt. of a powdery sintering aid and firing the compact in the air. The ceramic material contains acicular multiple oxide grains B21 uniformly dispersed in the matrix phase 20 of α-alumina.