两步合成法制备高纯铌镁酸铅-钛酸铅复合粉体及其性能表征

Two step synthesis and characterization of high purer PMN-PT composite powder

采用改进的两步合成法在较低温度下制备高纯度的铌镁酸铅-钛酸铅粉体复合材料,第1步,以氧化镁或碱式碳酸镁为镁源,与五氧化二铌混合,制备铌镁酸;第2步,在铌镁酸中加入碱式碳酸铅与二氧化钛或加入醋酸铅与二氧化钛,制备铌镁酸铅-钛酸铅材料。通过XRD定性分析产品的物相组成,结合SEM对产品形貌的观察和TG-DSC对前驱体的热处理过程进行分析,研究不同原料体系、合成温度、球磨时间等因素对产品纯度的影响。结果表明,在相同工艺条件下,用碱式碳酸镁制备的铌镁酸纯度更高;选择醋酸铅为铅源有利于提高铌镁酸铅-钛酸铅的纯度。采用混合球磨分散工艺和选择熔点低、受热逐步分解特性的醋酸铅晶体为原料,有利于降低铌镁酸铅-钛酸铅风复合粉体的合成温度和提高产品纯度。

High purity PMN-PT composite powders was synthesized by two step method at lower temperature,two step synthesis method was used.Firstly,MgO or 4MgCO3·Mg(OH)2·4H2O were mixed with Nb2O5 to get MgNb2O6.Secondly,2PbCO3·Pb(OH)2 and TiO2 were put into MgNb2O6,or Pb(Ac)2·3H2O and TiO2 were put into MgNb2O6,to synthesize PMN-PT powder.The phase composition of the product was qualitatively analyzed by XRD.The morphologies of the powders and the thermal behavior of precursor were analyzed by SEM and TG-DSC.The effects of raw material system,synthesis temperature and milling time on the purity of product were investigated.The results show that under the same technological conditions,the purity of MgNb2O6 prepared by 4MgCO3·Mg(OH)2·4H2O is higher.Using Pb(Ac)2·3H2O as Mg source is benefit to improve the purity of PMN-PT.The lower synthesis temperature and higher product purity of PMN-PT powders can be obtained by using Pb(Ac)2·3H2O crystal with lower melting point and gradually thermal decomposition as raw materials.