| 摘要 |
A die material particularly suitable for the making of castings or the like, comprises 50 to 80 parts of magnesium oxide, 10-40 parts of alumina, 2 to 6 parts of monohydrated ammonium phosphate, and 1 to 4 parts of dihydrated ammonium phosphate. The dry blend thus formed, when mixed with a chilled liquid binder containing a collodial silica sol of about 40 weight percent solids content in the ratio of one portion of the liquid binder and from 2 to 5 portions of the dry blend, forms a ceramic slurry which can be readily set in hot water within 4 to 10 minutes. The set ceramic casting is then dry heated to about 250 DEG F. for one to two hours. Molten metal is then applied on the casting for forming a metal jacket to use in dental prostheses. |
