Opal glasses having an apatite opacifying phase
AssigneeCorning Glass Works
InventorsJames E. Flannery, John L. Stempin, Dale R. Wexell
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Abstract
This invention is directed to spontaneous opal glasses containing an apatite opacifying phase and exhibiting a softening point of at least 740.degree. C., excellent chemical durability, and a temperature interval between the high temperature crystallization liquidus and the emulsion liquidus greater than 50.degree. C. The glasses consist essentially, in weight percent on the oxide basis, of ______________________________________ SiO.sub.2 50-63 Na.sub.2 O 5.5-10 Al.sub.2 O.sub.3 10-14 K.sub.2 O 0-10 P.sub.2 O.sub.5 3.5-7 BaO 0-10 PbO 2-12 CaO 0-2.5 B.sub.2 O.sub.3 1-4 SrO 0-8 F 1.5-4 BaO + CaO + SrO At Least 3 mole % ______________________________________
Claims3
A spontaneous opal glass exhibiting a dense white appearance, a softening point of at least 740.degree. C., excellent chemical durability, a temperature interval between the high temperature crystallization liquidus and the emulsion liquids greater than 50.degree. C., and containing as the predominant crystal phase a member selected from the group of Ca.sub.5 F(PO.sub.4).sub.3, Sr.sub.5 F(PO.sub.4).sub.3, Ba.sub.5 F(PO.sub.4).sub.3, (Ca.sub.5-x Ba.sub.x)F(PO.sub.4).sub.3 solid solution, (Sr.sub.5-x Ba.sub.x)F(PO.sub.4).sub.3 solid solution, (Ca.sub.5-x Sr.sub.x)F(PO.sub.4).sub.3 solid solution, (Sr.sub.5-x Ca.sub.x)F(PO.sub.4).sub.3 solid solution, (Ba.sub.5-x Ca.sub.x)F(PO.sub.4).sub.3 solid solution, and (Ba.sub.5-x Sr.sub.x)F(PO.sub.4).sub.3 solid solution, said glass consisting essentially, expressed in terms of weight percent on the oxide basis, of
- ______________________________________ SiO.sub.2 50-63 Na.sub.2 O 5.5-10 Al.sub.2 O.sub.3 10-14 K.sub.2 O 0-10 P.sub.2 O.sub.5 3.5-7 BaO 0-10 PbO 2-12 CaO 0-2.5 B.sub.2 O.sub.3 1-4 SrO 0-8 F 1.5-4 BaO + CaO + SrO At Least 3 mole % ______________________________________
Dependencies are inferred from the claim text.