| 摘要 |
PURPOSE:To obtain a highly pure alumina ceramic enhanced in the corrosion resistance and the creep resistance by specifying the content of Al2O3 and the diameter of crystal particles in the sintered product. CONSTITUTION:The objective alumina ceramic has an Al2O3 content of <=99.8wt.%, an average crystal particle diameter of >=2mum in the sintered product and a creeping rate of <=2.5X10-3/hr at 1400 deg.C. When the Al2O3 content is below 99.8wt.%, the creep resistance and the corrosion resistance are lowered and impurities in the product are increased. One kind or more of SiO2, MgO and CaO is added to the ceramic as a sintering auxiliary in addition to the Al2O3. When the average crystal particle diameter of the sintered product is below 2mum, the corrosion resistance and the creep resistance are deteriorated. The average crystal particle diameter is preferably <=40mum for the employment of the ceramic as a structural member, because the flexural strength of the ceramic is lowered when the average crystal particle diameter is enlarged. |
