烧结气氛对KNN基无铅压电陶瓷性能的影响

本文利用传统固相烧结法制备（K0.47Na0.47Li0.066）（Nb0．94Sb0．06）0.96%Ta0.04O3（简称KNLNST）无铅压电陶瓷，通过在烧结过程中添加与基方相同成分的粉料作为保护气氛，定量研究了不同的烧结气氛对KNLNST无铅压电陶瓷性能的影响。实验表明添加30wt％气氛粉料时所得陶瓷压电介电性能得到明显提高：d33=235pC／N，Tε33/ε0=1218，tanδ=0．0420，kp=42．5％，k1=43％，Qm=54，Pr=18．5μC／cm^2，Ec=1．61kV／mm。相对于不添加气氛粉料时，陶瓷压电铁电性能d33、kp、k1，Pr分别提高13．0％、32．4％、48．3％、14．9％，介电损耗tanδ下降64．3％。本研究结果有助于充分挖掘含有易挥发性元素陶瓷材料的优良压电介电性能。

Effects of Sintering Atmosphere on the Microstructure and Electrical Properties of KNN Based Lead--Free Piezoelectric Ceramics

Lead -- free piezoelectric ceramics （K0.47 Na0. 47 Li0.06 ） （ Nb0. 94 Sb0.06 ） 0. 96 Ta0.04 O3 （abbreviated as KNLNST） were fabricated successfully by using conventional solid--state reaction processing under different sintering atmospheres. By forming compensating atmosphere with addition of different amounts of powders of the same chemical composition of the sintering disks, the sinterability, densification and properties of the resulting ceramics were obviously improved. The results show that the optimum sintering atmosphere is achieved with compensating powders of 30 wt% the total weight of sintering disks, under which the sintered ceramics show good electrical properties of d33 = 235 pC/N, ε33^T/ε0 = 1218, tanδ =0. 0420, kp = 42. 5%, kt= 43%, Qm= 54, Pr= 18. 5 μC/cm2, Ec= 1.61 kV/mm. Compared with ceramics sintered without compensating atmosphere, the electrical properties d33, kp, kp and Pr are improved by 13.0%, 32.4%, 48. 3% and 14. 9% respectively, whereas the dielectric loss tanδ is decreased largely by 64. 3%. The technique proposed in this study may be generally extended to enhance the properties of ceramics containing volatile elements fabricated by conventional solid--state processing.