Improvements relating to opacifiers for porcelain enamels and to porcelain enamels containing such opacifiers

摘要

534,559. Enamels. FERRO ENAMEL CORPORATION. March 12, 1940, No. 4600. Convention date, March 13, 1939. [Class 56] An opacifier for enamels has the following molecular composition :-Sb 2 O 5' 1 or 3 TiO 2 , 2 CaF 2 , 2.5 CaO. If desired, 0.75 mols. of K 2 O and 0.75 mols. of ZrO 2 may be included. The material is made by sintering a mixture of calcium carbonate, fluor-spar, titania, and antimony oxide, together with potassium nitrate and zirconium oxide if required. The percentage compositions of a number of batches are given in the Specification. The opacifier may be employed as a mill addition, or part of the material may be added to the enamel batch and melted with the frit.