| 摘要 |
PURPOSE:To improve strength at high temp. by mixing two or more kinds selected from refined clay minerals, Bayer Al2O3, and silica so that composition ratio is regulated to a mullite-forming range, grinding the resulting mixture, mixing SiC powder and binder with the above mixture, and then subjecting the resulting mixture to compacting and sintering. CONSTITUTION:A compounded raw material is prepared by mixing two or more kinds selected from refined clay minerals, Bayer Al2O3, and silica so that the composition ratio of Al2O3 to SiO2 is regulated to a mullite-forming range. The above compounded raw material is subjected to wet grinding so that grains of <=5mum grain size comprise >=90% of the whole grains, and then, an SiC powder of <=50mum grain size is added to the above compounded raw material by 5-40wt.% and they are mixed. The resulting mixture is dried, cracked, compacted by the use of an organic binder, such as PVA, and subjected to hydrostatic pressing at >=1000kgf/cm<2>. The resulting green compact is subjected to temp.-rise at a rate of 50-200 deg.C/hr and sintered at >=1600 deg.C for 1-3hr, by which a mullite sintered compact can be obtained. |
