| 摘要 |
Ceramic glass products of high mechanical strength and good electrical properties predominantly composed of synthetic magnesium silicate crystals are formed from a melt comprising MgO (20-50%), SiO2 (20-50%), Al2O3 (5-20%) and a fluxing agent (5-15%) which may be one or more of Na2O, B2O3, K2SiF6 and K2O. After cooling the vitreous mass is first re-heated to 850-900 DEG C. for 15 minutes to 2 1/2 hours to initiate crystallization then raised to 1050 DEG C. for 1 to 8 hours to give a homogeneous nitro crystalline mass composed predominantly of synthetic magnesium silicate crystals. Magnesite (MgCO3) kyanite (Al2SiO2) and spinel (MgAlO4) may be used as batch materials. In forming a seal with metal the metal part is placed in a centrifugal mould and the molten glass poured in. After centrifuging and cooling, the composite article is subjected to the heat treatment to crystallize the glass. The material is also useful for bonding materials such as alumina, magnesia, silicon carbide, and mica. |
