烧结温度对PNW-PMN-PZT陶瓷结构和力学性能的影响

Effects of Sintering Temperature on Structures and Mechanical Properties of PNW-PMN-PZT Ceramics

CeO2掺杂Pb0.94Sr0.06(Ni1/2W1/2)0.02(Mn1/3Nb2/3)0.07(Zr0.51Ti0.49)O3(PNW-PMN-PZT)陶瓷采用传统固相烧结法制备。借助X-射线衍射(XRD)、扫描电子显微镜(SEM)、X-射线能谱分析(EDAX)及密度、硬度和弯曲强度研究了烧结温度对陶瓷结构和机械性能的影响。研究发现,烧结温度的提高可使三方-四方相变、晶体四方度和晶粒尺寸增大,而使晶粒表面的残余应变减小。EDAX结果表明,材料组成和结构的不均匀性随烧结温度的提高而加剧,过高的烧结温度可导致Ni、Ce元素在晶界严重偏析积聚。1000℃烧结的陶瓷具有最佳的力学性能,这与合适烧结温度对材料晶粒尺寸、残余应变、组成和结构的均匀性以及气孔率的影响有关。

The CeO_2 doped Pb_(0.94)Sr_(0.06)(Ni_(1/2)W_(1/2))_(0.02)(Mn_(1/3)Nb_(2/3))_(0.07)(Zr_(0.51)Ti_(0.49))_(0.91)O_3(PNW-PMN-PZT) ceramics were prepared by conventional solid reaction method.The structures of the ceramics sintered at different temperature were investigated by means of X-ray diffraction(XRD),scanning electron microscope(SEM) and energy dispersive analysis of X-rays(EDAX),and the mechanical properties were studied through density,hardness and flexural strength.It was found that the improvement of the sintering temperature could increase the phase transition from rhombohedral to tetragonal,the crystal tetragonallity and the grain size,while decrease the remnant strain on the surface of grains.The EDAX results indicate that the compositional and structural non-homogeneity of the materials increased with the improvement of the sintering temperature and the serious segregation and accumulation of Ni and Ce elements at grain boundaries were caused by higher sintering temperature.So,the ceramic sintered at 1000℃ possesses the most optimal mechanical properties,which should be attributed to the effects of the suitable sintering temperature on the grain size,the remnant strain,the compositional and structural homogeneity and the porosity of the materials.