| 摘要 |
<p>Partially devitrified porcelain compositions are provided which are comprised of a mixture, based on its oxide content, of barium oxide (BaO), magnesium oxide (McO) or a mixture of magnesium oxide with certain other oxides, boron trioxide (B2O3) and silicon dioxide (SiO2). In accordance with this invention the porcelain compositions are applied to the metal core and fired to provide a partially devitrified porcelain coating on the metal core. The coating has a very low viscosity at its initial fusion point and then almost instantaneous high viscosity due to partial devitrification. The fired coating has a deformation temperature of at least 700 DEG C. and a high coefficient of thermal expansion of at least about 110x10-7/ DEG C.</p> |
