| 摘要 |
<p>To prepare an overglaze color for applying on a pottery glaze, there are mixed together silica rock and kaolin which together supply silicon dioxide and alumina, and boron oxide (10 - 40 wt %), an alkali metal carbonate (to provide the corresponding oxide) (2-17%), hafnium oxide, and optionally a rare earth element oxide (0.1-15%) or an oxide of zinc, bismuth, zirconium, strontium and/or an alkaline earth metal, the mixture is pulverized, melted at 1000 - 1400 DEG C for 0.5 to 2 hours, matured, pulverized and the resulting frit is mixed with a pigment, e.g. copper carbonate, ferric oxide, antimony trioxide or cobalt oxide. The frit contains silicon dioxide (30-70 wt %). alumina (0.1-15%) and said other oxides, and a dispersion is painted onto a glaze, and although it contains no lead or cadmium it has good color developing property and a thermal expansion coefficient similar to a conventional overglaze; it can be fired at 700 to 900 DEG C, and is acid- and alkali-resistant.</p> |
