| 摘要 |
Partially crystallized ceramic articles is prepared by firing at low temperatures of 800 DEG to 1100 DEG C., a mixture consisting essentially of, (a) 40 to 50 wt. % of powdered, noncrystalline glass consisting essentially of 10 to 55 wt. % of at least one selected from the group consisting of CaO and MgO, 45 to 70 wt. % of SiO2, 0 to 30 wt. % of Al2O3, 0 to 30% of B2O3 and up to 10% impurities, the powder size of said glass being at least 4.0 m2/g in terms of specific surface area measured by the BET Method; and (b) 60 to 50 wt. % of powdered Al2O3 and the ceramic article is composed essentially of a noncrystallized glass phase, alumina and at least one of crystallized glass phase among anorthite, wollastonite, cordierite and mullite formed by partially crystallizing the glass (a). The ceramic articles exhibit a very high flexural strength well comparable with alumina substrate, together with greatly improved dielectric constant and thermal expansion and thus are especially useful in making multi-layer ceramic substrates for electronic applications. |
