| 摘要 |
PURPOSE:To improve durability to thermal shock and contamination resistance to a melt by molding and sintering a mixture of high purity starting material for MgO and fine Al2O3 powder with fine TiO2 powder. CONSTITUTION:High purity starting material for MgO having >=99.0wt.% purity and <=10mum average particle size, e.g., magnesia clinker and 0.005-1.0wt.% fine Al2O3 powder having <=0.1mum average particle size are mixed with fine TiO2 powder having <=10mum average particle size added by 0.1-2wt.% of the total amt. of the starting material and the Al2O3 powder, a binder such as polyvinyl butyral is added to the mixture by 0.5-5.0wt.% of the amt. of the starting material and they are press-molded under 500-2,000kg/cm<2> pressure to obtain a molded body. This molded body is heated from ordinary temp. to a prescribed temp. of 400-600 deg.C at 100-200 deg.C/hr heating rate, further heated from the prescribed temp. to a sintering temp. of 1,500-1,800 deg.C at 100-250 deg.C/hr heating rate and sintered by holding at the sintering temp. for 1-2 hr. |
