Single-layer submicron-thick BaTiO_3 coatings from poly(vinylpyrrolidone)-containing sols: Gel-to-ceramic film conversion, densification, and dielectric properties
Single-layer submicron-thick BaTiO_3 coatings from poly(vinylpyrrolidone)-containing sols: Gel-to-ceramic film conversion, densification, and dielectric properties
复制标题
由含聚乙烯吡咯烷酮的溶胶制成的单层亚微米厚 BaTiO_3 涂层：凝胶到陶瓷膜的转化、致密化和介电性能
DOI：
--
复制
发表时间：
2001
期刊：
影响因子：
--
通讯作者：
Atsushi Higuchi
中科院分区：
文献类型：
--
作者：
H. Kozuka;Atsushi Higuchi
以摩尔比为Ba（CH 3COO）2：Ti（OC 2 H5）4：PVP：CH 3COOH：H2O：C2 H5 OH = 1：1：0.5：27：4：5的聚乙烯吡咯烷酮（PVP）溶液为原料，采用不重复的一步浸涂法制备BaTiO 3涂层。在210 °C以下，溶剂和CH_3COOH蒸发，PVP在210-360 ° C分解，CH_3COO^-在440 °C以下分解，在500-610 °C晶化。PVP的分解伴随着缩合反应的进行，这导致膜厚度显著减小。在700 °C等温加热时，可得到厚度为0.9 μm的无裂纹BaTiO_3薄膜。当凝胶膜在360 °C和然后在700 °C下等温加热时，膜变得更致密。在360 °C等温热处理的薄膜具有较高的介电常数，约为290。PVP分解速率较慢被认为是膜致密化的关键。
BaTiO_3-coating films were prepared from a solution containing poly(vinylpyrrolidone) (PVP) of molar composition Ba(CH_3COO)_2:Ti(OC_2H_5)_4:PVP:CH_3COOH:H_2O: C_2H_5OH = 1:1:0.5:27:4:5, via nonrepetitive, single-step dip-coating. The gel films were found to be converted into BaTiO_3 films via evaporation of the solvent and CH_3COOH below 210 °C, decomposition of PVP at 210–360 °C, decomposition of CH_3COO^− below 440 °C, and crystallization at 500–610 °C. The decomposition of PVP was accompanied by the progress of the condensation reaction, which resulted in significant reduction in film thickness. When the gel films were heated isothermally at 700 °C, crack-free BaTiO_3 films as thick as 0.9 μm were obtained. When the gel films were heated isothermally at 360 °C and then at 700 °C, the film became denser. Higher dielectric constants around 290 were found for the film that underwent the isothermal heat treatment at 360 °C. A slower rate of PVP decomposition was thought to be the key for the film densification.