利用固相反应法合成了Ca1-x(KLa)x/2Bi2Nb2O9(x=0～0.20)(xKLaCBNO)铋层状陶瓷,分析不同KLa掺杂量对CaBi2Nb2O9(CBNO)基陶瓷微观结构、介电、压电及电导性能的影响.XRD分析表明KLa的引入未改变CBNO陶瓷的单相结构.SEM和介电系数温度谱结果分别显示,KLa掺杂量的增加,细化尺寸趋于一致,而居里温度(Tc)从943℃降低至875℃,其峰值介电常数减小、峰值介电损耗增大.当掺杂量x=0.1时,样品的高温电阻率较纯CBNO显著升高,压电系数d33由5.2pC/N提高到15.8pC/N,居里温度高达870℃,说明A位(KLa)掺杂改性后的CBNO陶瓷在高温传感器等领域具有潜在的应用前景.%High curie temperature piezoelectric ceramics based on KLa-doped Ca1-x(KLa)x/2BiNb2O9(x=0-0.20) were prepared by a conventional solid state reaction method. Crystal structure and microstructures of Ca1-x(KLa)x/2Bi2Nb2O9, ceramics were characterized by XRD and SEM. XRD patterns show that the crystal structures are a single phase of bismuth oxide layer structure having general formula (Bi2O2)2+(Am-1BmO3m+1)2- with m = 2. The grains of polished and thermally etched surfaces revealled a plate-liked morphology. The Curie point (Tc) decreases obviously whereas the piezoelectric activity of CBNO ceramics is significantly improved by the doping of potassium and lanthanum. The KLa-doped CBNO materials have an electrical conductivity value 1-2 orders of magnitude lower than undoped samples. The thermal depoling behavior of Ca1-x(KLa)x/2Bi2Nb2O9 ceramics shows that all of them have a high Curie point (Tc≥850℃) and show good resistance to thermal depoling up to temperatures close to their Curie points. The results showed that the excellent properties is obtained in the ceramics with composition of x=0.1, i.e. d33=15.8 pC/N, Tc=870℃ and the DC conductivity is one order of magnitude smaller than that of undoped CBNO. All the results suggest that the doped CaBi2Nb2O9 is a potential material for high temperature sensor.
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