| 摘要 |
PROBLEM TO BE SOLVED: To stabilize color tone after baking and to improve effect for shielding metal color by incorporating specified wt.% of CeO2 and aluminosilicate glass as a material for shielding the metal color of a metal base material for dentistry during baking. SOLUTION: An opaque porcelain material for shielding metal color of a metal base material for dentistry during baking contains 15-50wt.% CeO2 and 40-50wt.% aluminosilicate glass. In addition, softening temp. of the porcelain material is pref. 700-900 deg.C, further preferably 800-900 deg.C. The compsn. of the porcelain is compounded with ingredients in such a way that linear thermal coefficient of expansion of the porcelain is at the same level or in a little low range (10.0-13.0×10<-6> / deg.C) in the temp. range of 25-450 deg.C in comparison with the linear thermal coefficient of expansion of dental precious metals. In addition, aluminosilicate glass has pref. a compsn. of 50-60wt.% SiO2 , 10-20wt.% Al2 O3 , 5-20wt.% K2 O, 5-20wt.% Na2 O, 0.1-2wt.% Li2 O, 0.1-2wt.% CaO and 0.1-2wt.% MgO.
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