| 摘要 |
PURPOSE:To obtain the title form suitable for agitation of molten metal, by expanding in a mold a slurry containing ceramic powder and a foaming agent, preliminarily calcining the resultant form and washing only the surface of the resulting preliminarily calcined form where gas introduction or blowout is to be made followed by full calcination of said form. CONSTITUTION:Ceramic powder and a foaming agent are added to water or a solvent to prepare a ceramic slurry 12, which is then poured into a mold 11 and expanded to make a form 16 with the interior as a porous matrix 14 and the exterior (the part being in contact with said mold 11 or a cover 13) as a dense skin layer 15. Thence, this form 16 is preliminarily calcined into a preliminarily calcined form 17, and its surface other than that where gas introduction or blowout is to be made is covered with a film 18 (e.g., of polyethylene, polyvinyl acetate) and washing is performed (using water, HCl, or HNO3). The resultant form 17 is subjected to full calcination, thus obtaining the objective gas blowout form. |
