保温时间对0.98（K0.5Na0.5）NbO3-0.02LaFeO3陶瓷电性能的影响.pdfVIP

Trans. Nonferrous Met. Soc. China 23(2013) 2984−2988 Effects of dwell time during sintering on electrical properties of 0.98(K Na )NbO −0.02LaFeO ceramics 0.5 0.5 3 3 Hua-lei CHENG, Wan-cheng ZHOU, Hong-liang DU, Fa LUO, Dong-mei ZHU State Key Laboratory of Solidification Processing, Northwestern Polytechnical University, Xi’an 710072, China Received 28 September 2012; accepted 24 March 2013 Abstract: The effects of dwell time on the phase structure, microstructure, and electrical properties were investigated for the 0.98(K Na )NbO −0.02LaFeO ceramics (abbreviated as 0.98KNN−0.02LF). All the ceramics sintered for different dwell time are 0.5 0.5 3 3 of pure phase and the peak intensity of the 0.98KNN−0.02LF ceramics becomes stronger with a longer dwell time. Denser microstructures with larger grain size are developed for the sample with a longer dwell time. The maximum dielectric permittivity decreases with increasing the dwell time, and the deteriorative dielectric properties are due to the increasing grain size and the domain wall motion. Ferroelectric properties results indicate that 2Pr value slightly decreases with increasing the dwell time, while the 2Ec value increases. Consequently, the 0.98KNN−0.02LF ceramic sintered at 1150 °C for 2 h shows optimum dielectric 2 properties (ε=2253 and tan δ5%) and ferroelectric properties (2P =34.51 μC/cm and 2E =5.07 kV/mm). r