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以钨酸和正硅酸乙酯(tetraethyl orthosilicate,TEOS)为原料,采用改进的溶胶–凝胶工艺,在Al2O3基底上制备WO3–SiO2复合薄膜,重点考查复合薄膜的烧结温度、物相组成及气敏性三者之间关系。用X射线粉末衍射仪和场发射扫描电子显微镜表征复合薄膜的微观结构,结果表明:在烧结温度为500℃与650℃时,复合薄膜为立方相和正交相混合相,复合薄膜的晶粒尺寸为25～30nm,分布均匀。650℃烧结时,对还原性挥发性有机化合物(volatileorganiccompounds,VOCs)气体中丙酮具有较好的敏感性。750℃烧结时,复合薄膜只有单一的正交相,晶粒尺寸在30nm左右,此时复合薄膜对氧化性气体NO2具有很好的敏感性与选择性,最低响应浓度(体积)为10–7,响应时间为2s,恢复时间约为10s。
The WO3-SiO2 composite film was prepared on Al2O3 substrate by using the improved sol-gel process with tungstic acid and tetraethyl orthosilicate (TEOS) as the raw materials, with emphasis on the sintering temperature, phase composition and gas Sensitivity of the relationship between the three. The microstructure of the composite films was characterized by X-ray powder diffraction (XRD) and field emission scanning electron microscopy (SEM). The results showed that the composite films were cubic phase and orthorhombic mixed phase at sintering temperature of 500 ℃ and 650 ℃. Size of 25 ~ 30nm, evenly distributed. When sintered at 650 ℃, it has good sensitivity to acetone in the volatile organic compounds (VOCs). When sintering at 750 ℃, the composite film has only a single orthogonal phase and the grain size is about 30nm. At this time, the composite film has good sensitivity and selectivity to the oxidizing gas NO2 with the lowest response concentration (volume) of 10-7 , Response time is 2s, recovery time is about 10s.