Ta掺杂和烧结气氛对KNN基无铅压电陶瓷的微观结构和压电性能的影响

Influence of Ta Doping Elements and Sintering Atmosphere on Microstructure and Electrical Properties for KNN-based Lead-free Piezoelectric Ceramics

为了探究掺杂以及不同烧结气氛对陶瓷的微观结构以及压电性能的影响。通过传统固相法制备并分别在空气和还原气氛条件下烧结了0.96K_(0.48)Na_(0.52)Nb_(1-x)Ta_(x)Q_(3)-0.04BaZr0_(3)-0.3%MnCO_(3)陶瓷。研究表明:不同气氛烧结的陶瓷均为纯钙钛矿结构,陶瓷相结构为菱方相与正交相共存,且Ta的掺杂抑制了氧空位的产生。当掺杂量为0.10时,还原烧结气氛下性能最优:d_(33)=172 pC/N,d_(33)^(*)=294 pm/V,k_(p)=24.9,ε_(33)^(T)=820,tanδ=0.021,且性能优于同组分在空气下烧结的样品(d_(33)=142 pC/N,d_(33)^(*)=220 pm/V,k_(p)=21.1,ε_(33)^(T)=593,tanδ=0.022)。还原气氛可以抑制晶粒生长,促进陶瓷的致密化,进而提高陶瓷样品的压电性能。

The ceramics of 0.96K_(0.48)Na_(0.52)Nb_(1-x)Ta_(x)Q_(3)-0.04BaZr0_(3)-0.3%MnCO_(3)were prepared via solid-state reaction and subsequent sintering in air and reducing atmospheres.The effects of Ta doping and sintering atmosphere on the microstructure and piezoelectric properties of ceramics were investigated.The results demonstrate that all the ceramics sintered in different atmospheres exhibit a pure perovskite structure.The phase structure of KNN-based ceramics is the coexistence of rhombohedral and orthorhombic phases.Also,the generation of oxygen vacancies is suppressed as Ta doping content is increased.When x=0.1,the ceramics sintered in a reducing atmosphere exhibit the optimum electrical properties (i.e.,d_(33)=172 pC/N,d_(33)^(*)=294 pm/V,k_(p)=24.9,ε_(33)^(T)=820,and tanδ=0.021),which are superior to the counterparts sintered in air atmosphere (i.e.,d_(33)=142 pC/N,d_(33)^(*)=220 pm/V,k_(p)=21.1,ε_(33)^(T)=593,and tanδ=0.022).It is indicated that sintering in a reducing atmosphere can suppress the grain growth,thus facilitating the densification of ceramics and improving the piezoelectric properties.