铜颗粒分散铌酸钾钠压电复合材料的制备与性能

Fabrication and properties of Cu-particle-dispersed potassium sodium niobate piezoelectric composites

在工业氮气(N2)气氛条件下制备了锂掺杂铌酸钾钠/铜(NKLN/Cu)压电复合材料,研究了铜含量对复合材料的相结构、密度、电学性能及力学性能的影响。结果表明:复合材料由NKLN陶瓷相和Cu金属颗粒两相组成,不同Cu含量复合材料的相对密度均达到95%以上。复合材料的介电常数随Cu含量的增加而急剧增加,压电常数和机电耦合系数随Cu含量的增加而减小,当Cu的体积分数达到20%时,NKLN/Cu复合材料的介电性能和压电性能均难以测量。NKLN/Cu复合材料的显微硬度随Cu含量的增加而降低,断裂韧性值随Cu含量的增加而升高,从铌酸钾钠陶瓷的1.01 MPa逐渐增至Cu的体积分数为40%时的2.81 MPa。

Lithium-modified potassium sodium niobate/copper（NKLN/Cu） piezoelectric composites were fabricated by protective sintering in a industrial nitrogen gas.The phase structure,density,electrical and mechanical properties were studied in relation to Cu content.The results show that the composites consists of only NKLN and Cu phases,the relative densities of the composites were all above 95 % theoretic densities.The relative dielectric constant r of the composites markedly increased with increasing Cu concentration.The piezoelectric constant d33 and electromechanical coupling factor kp decreased as the volume of Cu was increases.When increasing Cu concentration up to 20%,the r,d33 and kp were hard to detect.The microhardness of the composites decreased with the addition of Cu.With increasing Cu content up to 40%,the fracture toughness KIC gradually increased from 1.01 MPa for monolithic NKLN ceramics to 2.81 MPa for NKLN-40%Cu composite.