(Ba,Sr)TiO_3/Mg_xZn_(1-x)O核-壳复合陶瓷的制备及表征

Characterizations of the core-shell structured BST composites nanopowders and ceramics

纳米粒子由于具有大量的潜在应用,近年来已引起人们极大的关注.通过纳米复合技术(如制备核壳结构的纳米粒子)可以使其获得更多的特殊性质.以氢氧化钡、氢氧化锶、钛酸丁酯为主要原料,采用化学溶液法,在80℃左右的温度下制备了钛酸锶钡纳米晶.硝酸镁和硝酸锌的混合溶液同钛酸锶钡混合并超声搅拌,在室温下制备了具有核壳结构的(Ba,Sr)Ti O3/MgxZn1-xO(BST/MZO)纳米晶.x射线衍射(xRD)和场发射扫描电子显微镜(FESEM)确定所制备样品为纯钙钛矿结构,透射电镜(TEM)表明产品的形貌是核壳结构小球,电子衍射图案进一步证实核和壳均是由十几个到几十个纳米的(Ba,Sr)Ti O3/MgxZn1-xO纳米晶组成的聚集体.采用常规的陶瓷制备技术获得具有核壳结构复合陶瓷,其介电性能明显改善.研究结果表明具有核壳结构的(Ba,Sr)Ti O3/MgxZn1-xO适合作为微波介电材料.

BST nanoparticles were directly synthesized from solution at 80℃ and then wrapped with zinc doped MgO in solution under ultrasonic dispersion at room temperature.This core-shell structure was analyzed by a conjunction of XRD, HRTEM and FE-SEM. The lattice cell parameter of BST core was found to have shrinkage. The lattice cell mismatch between core and shell make a fluctuation of lattice cell parameter of BST core. The nanoparticles can also be observed by FESEM in fractured grains of the ceramics. The diel...