BNT-BZT压电陶瓷准同相界处材料性能的研究

研究(1-x)(Bi_(0.5)Na_(0.5))TiO_3-xBa(Ti_(0.95)Zr_(0.05))O_3(BNT-BZT)体系陶瓷的准同型相界,以及陶瓷材料的微观结构和性能之间的关系。BNT-BZT陶瓷体系在富BNT和Zr含量低的区域存在准同型相界,在相界附近可能得到性能优良的无铅压电陶瓷,相界点在x≈0.1这个区域内。将BNT陶瓷和BZT陶瓷固溶后能够得到d_(33)大于150 pC/N,居里温度在240℃左右,介电常数在900左右的性能良好的无铅压电陶瓷。

PNS-PZ-PT压电陶瓷烧结和性能的研究

对Pb(Ni1/3／3Sb2／3)-PbZrO3-PbTiO3陶瓷烧结和压电性能的研究表明:当含有48mol％PbTiO3和少于10mol％Pb (Ni1／3Sb2／3)的粉体在850℃下煅烧2 h,得到单一钙钛矿结构,但是如果Pb(Ni1/3Sb2／3)组成在12mol％～14mol％之间时,则三方相和四方相共存。所以材料的准同相界在Pb(Ni1/3Sb2/3)=12mol％,PbZrO3=40mol％,PbTiO3=48mol％。当该组分在1260℃至1280℃烧结时得到的烧结物密度最大为7．8g／cm3。扫描电镜结果表明在1280℃时材料烧结气孔率最小。当处于准同相界的组分在1280℃烧结时,材料的机电耦合系数Kp和机械品质因数Qm分别达到最大值0．488和最小值292．5。

BiScO_(3)-BiFeO_(3)-PbTiO_(3)-BaTiO_(3) high-temperature piezoelectric ceramic and its application on high-temperature acoustic emission sensor

Piezoelectric ceramic based high-temperature acoustic emission(AE)sensor is required urgently in the structural health monitoring of high-temperature fields.In this research,a series of 0.45(BiSc_(x)O_(3)-BiFe_(1-x)O_(3))-0.48PbTiO_(3)-0.07BaTiO_(3)(BSc_(x)Fe_(1-x)-PT-BT,n(Sc)/n(Fe)=0.4/0.6-0.6/0.4)ceramics with both high Curie temperature and large piezoelectric constant were presented.The structure and electrical properties of BSc_(x)Fe_(1-x)-PT-BT ceramics as a function of n(Sc)/n(Fe)have been systematically investigated.All the ceramics possess a perovskite structure,and the phase approaches from the rhombohedral toward the tetragonal phase with the decrease of n(Sc)/n(Fe).The BSc_(0.5)Fe_(0.5)-PT-BT and BSc_(0.5)Fe_(0.5)-PT-BT piezoelectric ceramics exhibit good piezoelectricity(d_(33)=250-281 pC/N),high Curie temperature(T_(C)=430-450℃)and excellent temperature stability.These improvements are greatly attributed to the balance between rhombohedral and tetragonal phase near morphotropic phase boundary with dense microstructure of ceramics.AE sensor based BSc_(0.5)Fe_(0.5)-PT-BT piezoelectric ceramic was designed,prepared and tested.The high-temperature stability of AE sensor was characterized through pencil-lead breaking with in situ high-temperature test.The noise of AE sensor is less than 40 dB,and the acoustic signal is up to 90 dB at 200℃.As a result,AE sensors based on BSc_(x)Fe_(1-x)-PT-BT piezoelectric ceramics are expected to be applied into the structural health monitoring of high temperature fields.

高居里点BiScO_3-PbTiO_3压电陶瓷介电压电性能研究

用通常的固相反应法制备了(1–X)BiScO3-XPbTiO3(X=0.60,0.62,0.64,0.66,0.68)系压电陶瓷,并对其进行了微结构和介电、压电性能研究。XRD分析表明,该系统在PbTiO3摩尔分数X=0.64时,存在准同相界,当X小于0.64或大于0.64时,陶瓷分别为菱方相和四方相结构。相结构在准同相界的试样具有最大的压电常数,其d33高达430pC/N。介温谱测试表明,该陶瓷体系居里温度为450℃左右,具有弛豫铁电体特征。