不同镁源反应物对反应烧结制备Pb(Mg_(1/3)Nb_(2/3))O_3陶瓷的影响

Effect of Mg Precursors on Reactive-sintering Properties of Pb(Mg_(1/3)Nb_(2/3))O_3

采用MgO和(MgCO3)4.Mg(OH)2.5H2O为不同镁源反应物,通过高温反应烧结工艺制备Pb(Mg1/3Nb2/3)O3(PMN)陶瓷,研究不同Mg源反应物对PMN陶瓷物相组成、相对密度及组织形貌的影响。结果表明:以MgO为前驱体时,由于其反应活性差,扩散和反应不均匀,导致烧结样品中有焦绿石相残留,且焦绿石相对晶界的钉扎阻碍作用使得致密化过程进行相对较慢,所得PMN样品致密度相对较低;而以(MgCO3)4.Mg(OH)2.5H2O为前驱体时,因其受热分解可以得到大比表面积、高反应活性的MgO,从而可以制得高致密度且具有单一钙钛矿相组成的PMN陶瓷材料。

Pb（Mg1.3 Nb2.3 ）O3 （PMN） ceramics have been fabricated via the high-temperature reactive sintering process by using MgO and （MgCO3）4 · Mg（OH）2 , 5H2O as the Mg precursors. The effect of Mg precursors on the phase composition, relative density and microstructure of ceramics was investigated. Due to the relatively low reactive activity of MgO, the pyrochlore phase was residual by using MgO as Mg precursor. The hindrance of pyrochlore phase on the movement of grain boundary lowers the densificating process and leads to the relatively low density. When （MgCO3）4 · Mg（OH）2 ·5H2O was used as the reactant, MgO with high reactive activity was generated from its thermal decomposition. The solid state reaction could be completed at low temperature. The pyrochlore-free PMN ceramics with high relative density were obtained.