| abstract |
An improved sintered ceramic core is used in a mold during the casting of a reactive metal. Prior to sintering, the core contains ceramic material which includes yttrium aluminate and alumina (Al2O3). It is preferred to have the ceramic material contain between 10% and 40% yttrium aluminate. Prior to sintering, the yttrium aluminate has a mean particle size of less than 20 microns and, preferably, less than 10 microns. Particularly advantageous results has been obtained by using yttrium aluminate having a mean particle size, prior to sintering, of approximately 3 microns. It is contemplated that the ceramic material will be utilized to form other articles, such as a mold, filter, or liner for a ladle, which are exposed to reactive metals during casting. |