ALUMINA-BASED COMPOSITE CERAMIC AND ITS PRODUCTION

PROBLEM TO BE SOLVED: To obtain an alumina-based composite ceramic having a fracture strength and a fracture toughness hardly being lowered even at >=1,400 deg.C, and usable as a functional material at a high temperature. SOLUTION: This alumina-based composite ceramic is obtained by dispersing a yttria-alumina composite fiber in a matrix of a polycrystal α-alumina. A mixed aqueous solution of yttrium ion and aluminum ion in a YAG composition is precipitated by a homogeneous precipitation method. Acetic acid and an organic binder is added to the product, and the obtained mixture is spun and baked to provide the yttria-alumina composite fiber. The obtained yttria-alumina composite fiber is mixed with an alumina slurry, and the resultant material is compacted and baked to provide the objective alumina-based composite ceramic.