凝胶注模法制备多孔BiScO3-PbTiO3高温压电陶瓷及性能研究

为了拓展BiScO3-PbTiO3体系陶瓷的应用领域，采用凝胶注模工艺，对初始固相体积分数10%的准同型相界附近的BiScO3-0.642PbTiO3 (记作BS-PT642)/混合物经球磨、注模、脱模、烘干、排胶，在1 100 ℃烧结，制备出多孔高温压电陶瓷.利用X射线衍射仪对多孔陶瓷进行物相分析，通过扫描电子显微镜观察样品的新鲜断面和抛光热腐蚀后表面的显微结构，并对其压电、介电和水声性能进行研究.研究表明，多孔BS-PT高温压电陶瓷为立方钙钛矿相结构，具有高静水压优值(HFOM)和高孔率结构，孔隙通道密实化清晰可见，没有显著的缺陷，且气孔之间相互连通，其中一个活跃的压电陶瓷相和一个被动空气相呈三维互连.样品的气孔率为31.8%，静水压优值为1 020×10-15 Pa-1，介电常数和压电常数分别为εr=620,d33=213 pC/N
In order to expand the application fields of BiScO3-PbTiO3 ceramics, porous BiScO3-0.642PbTiO3 (BS-PT642) high temperature piezoelectric ceramics with interconnected pore channels were prepared using the novel gel-casting method. In this method, the BS-PT642 slurries with 10% initial solid phase was prepared by ball milling, and then cast into molds, dried, removed from the molds and sintered at 1100 ℃. The porous ceramics were characterized using X-ray diffraction and scanning electron microscopy. The ceramics were pure tetragonal perovskite. Properties of the porous ceramics, including porosity, piezoelectric coefficient (d33), dielectric properties (εr) and hydrostatic figure of merit (HFOM) were measured. The ceramics with high HFOM showed high porous structure, consisting of fully dense BS-PT walls without any noticeable defects, such as cracks or pores. From the viewpoint of their connectivity, an active piezoelectric ceramic phase and a passive air phase were three-dimensionally interconnected. The HFOM of 1 020×10-15 Pa-1 was achieved for the ceramics with a porosity of 31.8%, as well as εr=620,d33=213 pC/N, respectively.