| 摘要 |
PURPOSE:To reduce the influence of temperature and humidity by forming a cavity of cordierite ceramics. CONSTITUTION:The cordierite ceramics consist basically of MgO, Al2O3, and SiO2, but oxide of at least one kind of metal among chromium, manganese, iron, cobalt, nickel, copper, zinc, lead, alkaline earth metal, and alkali metal and oxide of at least one kind of metallic oxide among tin, titanium, and zirconium upon occasion are compounded. This material is formed into a cavity body 2 having 1-5mm. thickness and sintered and then a metallic layer 7 having 1-50mum thickness is formed over its internal surface. A ceramic layer 6 is dense, so water absorptivity is eliminated substantially. Therefore, the influence of temperature is reduced and the resonance frequency never varies with humidity. |
