| 摘要 |
PURPOSE: To produce a sintered compact having satisfactory productivity and translucency and free from voids and defects in an arbitrary shape at a low cost with high productivity without adversely affecting the environment by mixing Al2 O3 powder with Y2 O3 powder, calcining the resultant mixture and specifying ratio in X-ray diffraction intensity. CONSTITUTION: Powdery Al2 O3 and powdery Y2 O3 each having >=99.0% purity >=5m<2> /g BET specific surface area and <=2μm particle diameter are mixed so that the ratio of Al2 O3 :Y2 O3 is regulated to 0.43:0.57 and the resultant mixture is calcined at 1,000-1,600 deg.C for >=0.5hr until >=50% rate of formation of YAG is attained. The calcined mixture is pulverized to prepare powdery starting material, a solvent is added and they are mixed and pulverized with a pot mill, etc., to obtain calcined particles having <=12μm particle diameter. These particles are dried, screened and press-compacted to >=2.1g/cm<3> density so as to minimize voids in a formed sintered compact. The resultant compact is heated to 1,600-1,900 deg.C max. temp. at 50-300 deg.C/hr rate of temp. rise at <=1×10Torr degree of vacuum and it is held at the max. temp. for 2-20hr to obtain the objective YAG sintered compact having a ratio in X-ray diffraction intensity satisfying the formula and contg. >=60% YAG having 30μm average grain diameter.
|
