| 摘要 |
PURPOSE:To provide an excellent alumina based ceramic composition which enables to fire at a lower temp. about 1300 deg.C and has excellent flatness <=1mum in the surface roughness of the obtained alumina insulator and is >=10<14>OMEGAcm in insulation resistance, in the alumina'-based ceramic composition of the alumina insulator for a carbon film fixed resistor and a metallic oxide film fixed resistor which are widely used in an electronic devices. CONSTITUTION:The total amount of Al2O3, SiO2, CaO and MgO components is 100 pts.wt. and the ratio ranges of these components are 88-94 pts.wt. for Al2O3, and 6-12 pts.wt. for the total amount of SiO2, CaO and MgO, and the ratios of these three components of the alumina-based ceramic composition are, by weight ratio, 5.25-5.75 SiO, 3.50-4.50 CaO and 0.25-0.75 MgO. Besides the composition is formed by adding 0.02-0.30wt.% ZnO or 0.05-0.20wt.% Fe2O3. |
