アルカリ炭酸塩を含浸付与したSiO₂系焼成皮膜の感湿特性

抄録

SiO₂ film consisting of a heat-treated mixture of silicone polymer and silica gel was prepared. Alkali metal carbonates (Li₂CO₃, Na₂CO₃ and K₂CO₃) were respectively doped into the film by a surface treatment. The humidity-sensing property was examined. The effects of heat treatment and exposure to high humidity air were studied after doping. By doping with different carbonates, the impedance of SiO₂ films became low at various humidities. The impedance value of the doped films with dopant showed the order of Li₂CO₃>Na₂CO₃>K₂CO₃. After a final heat treatment and aging in high humidity air after doping, the humidity-sensing characteristics of the films scarecely change with exposure to indoor atmosphere. This effect of aging could be caused by the stable formation of hydration water to alkali metal carbonate.