微觀組織與電性能
(1. 桂林電子科技大學(xué) 廣西信息材料重點(diǎn)實(shí)驗(yàn)室，桂林 541004；
2. 桂林工學(xué)院 電子與計(jì)算機(jī)系，桂林 541004)
摘 要: 采用傳統(tǒng)陶瓷制備方法，制備一種新型無鉛壓電陶瓷 (1−x)Bi0.5(Na0.82K0.18)0.5TiO3-xBiCrO3 (BNKT-BCx)。研究Bi基鐵電體BiCrO3對(duì)BNKT-BCx陶瓷晶體結(jié)構(gòu)和壓電介電性能的影響。結(jié)果表明：在所研究的組成范圍內(nèi)，陶瓷材料的主體結(jié)構(gòu)為純鈣鈦礦固溶體，微量BiCrO3(x=0~0.02，摩爾分?jǐn)?shù))不改變陶瓷的晶體結(jié)構(gòu)；當(dāng)BiCrO3含量x＞0.02時(shí)，晶體結(jié)構(gòu)由三方、四方共存轉(zhuǎn)變?yōu)閭瘟⒎浇Y(jié)構(gòu)，并出現(xiàn)明顯的第二相；當(dāng)x=0.015時(shí)，d33=168 pC/N；當(dāng)x=0.01時(shí)，kp=0.32，為該體系壓電性能的最大值；隨BiCrO3含量的增加，陶瓷的低溫介電反常峰向低溫移動(dòng)，高溫介電反常峰向高溫移動(dòng)，反鐵電相區(qū)域增加，彌散指數(shù)增加。
關(guān)鍵字: 鈦酸鉍鈉；無鉛壓電陶瓷；壓電性能；鈣鈦礦結(jié)構(gòu)
（1. Guangxi Key Laboratory of Information Materials, Guilin University of Electronic Technology, Guilin 541004, China;
2. Department of Electron and Computer, Guilin University of Technology, Guilin 541004, China）
Abstract:A new (Bi0.5Na0.5)TiO3-based lead-free piezoelectric ceramics, (1−x)Bi0.5(Na0.82K0.18)0.5TiO3-xBiCrO3 (BNKT-BCx), was prepared by a conventional ceramic sintering technique. The effect of Bi-based ferroelectrics of BiCrO3 on the crystal structure, dielectric and piezoelectric properties was investigated. X-ray diffraction patterns indicate that trace BiCrO3 addition(x=0−0.02) causes insignificant change in crystal structure, and an obvious secondary phase is observed in the samples with x＞0.02. The piezoelectric constant d33 and the electromechanical coupling factor kp of the ceramics attain maximum values of 168 pC/N and 0.32 near morphotropic phase boundary (MPB) that co-existence between rhombohedral and tetragonal. With increasing BiCrO3 content, the antiferroelectric phase zone gets broader and the diffuse coefficient increases.
Key words: sodium bismuth titanate; lead-free piezoelectric ceramics；piezoelectric properties; perovskites structure
