| 摘要 |
PURPOSE:To improve the corrosion resistance of Si3N4 ceramics to molten steel, etc., without deteriorating the original high strength characteristics of Si3N4 by incorporating specified amts. of ZrO2 and Al2O3, MgO, Y2O3 or CaO into the ceramics. CONSTITUTION:Desired high strength ceramics having high corrosion resistance is composed of 5-50wt.% ZrO2, <=10wt.% at least one among Al2O3, MgO, Y2O3 and CaO and the balance Si3N4. ZrO2 can improve the corrosion resistance of Si3N4 ceramics to molten steel, etc., and at least one among Al2O3, MgO, Y2O3 and CaO acts as an Si3N4 sintering assistant and exists on grain boundary layers to inhibit the destabilization of ZrO2. The high strength ceramics is suitable for use as material of a tool for steel such as an immersion nozzle. |
