| 摘要 |
1,254,717. Flux for ceramic compositions; ceramics. UNITED STATES BORAX & CHEMICAL CORP. 28 Nov., 1969 [3 Dec., 1968], No. 57372/68. Headings C1J and C1M. A flux for a ceramic composition comprises a ground vitreous frit consisting of (weight per cent) :SiO 2 20-55 ; B 2 O 3 40-45 ; CaO and/or MgO 5-30 ; and Na 2 O 0-15. Such a flux may be formed by a mixture of compounds to give the appropriate oxide analysis on fusing, heating (e.g. to above 1000‹ C:) to fuse the mixture, cooling to solidify the melt: and grinding the product. The mixture may be of calcium or magnesium oxide, hydroxide or borate, a sodium borate (e.g. anhydrous sodium tetraborate) and silica (e.g. silica precipitated from a silica sol). Boric acid may also be included. The flux, with or without a conventional flux, is included in a ceramic composition also comprising clay and flint. Preferably less than 15% by weight of flux is used, and preferably no more than half the total flux is a conventional flux. The composition may be fired at, e.g., 1030- 1230‹ C. to form a ceramic, which may be glazed. |
