【摘要】 利用聚乙烯吡咯烷酮(Polyvinylpyrrolidone,PVP)添加到勃姆石溶胶/纳米α-A l2O3粒子体系中形成纳米复合浆料,采用旋涂、热处理的过程制备出具有一定厚度的A l2O3绝缘涂层,结果表明:PVP的添加能改变复合浆料中纳米α-A l2O3粒子的分散稳定性,进而调节涂层的结构以及电性能。当PVP与勃姆石溶胶中[A l3+]之间的物质的量比xPVP=1.2左右时,涂层介电击穿强度达到最大值~67kV/mm。由于纳米α-A l2O3粒子的引入,空间电荷极化成为涂层内部主要极化机制。更多还原

【Abstract】 Al₂O₃ coating for electrical insulation was fabricated by spinning composite slurry containing boehmite sol,nano-sized α-Al₂O₃ particles and polyvinylpyrrolidone（PVP） additive.The results show that the addition of PVP changes the suspension stability of nanosized α-Al₂O₃ particles in composite slurry and finally adjusts the density and properties of obtained Al₂O₃ coating.When the molar ratio(x_PVP) of PVP to the Al³⁺ in boehmite sol is 1.2,the obtained coating is dense and uniform with the highest dielectric breakdown strength of ～67kV/mm.Because of the higher quantity of grain boundaries and interface defects of well-dispersed nanosized α-Al₂O₃ particles in coating,the space-charged polarization will be established and become the dominant polarization mechanism in coating,which largely influences the dielectric loss and dielectric constant.更多还原