Effect of Microwave-Assisted Synthesis and Sintering of Lead-Free KNL-NTS Ceramics

Materials

María Guadalupe Navarro-Rojero¹  María Dolores Salvador²  Amparo Borrell²  Anggel Lagunas-Chavarría²  Rut Benavente²  Jose Manuel Catalá-Civera³ 

[1] Advance Technology Centre (CIATEQ A.C.), Av. del Retablo 150, Col. Constituyentes Fovissste, Querétaro 76150, Mexico;Instituto de Tecnología de Materiales (ITM), Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain;Instituto de las Tecnologías de la Información y Comunicaciones (ITACA), Universitat Politècnica de València, Camino de Vera, s/n, 46022 Valencia, Spain;

关键词: KNL-NTS ceramics;    synthesis;    calcination;    microwave processing;    piezoelectric properties;   

DOI  :  10.3390/ma15113773

来源: DOAJ

【 摘 要 】

Lead-free piezoelectric powders (K_0.44Na_0.52Li_0.04)(Nb_0.82Ta_0.10Sb_0.04)O₃ were obtained by conventional and microwave-assisted reactive heating. Firstly, the synthesis of the material was carried out following the mixed oxide route and employing both traditional methods and microwave technology. Thermogravimetry, X-ray diffraction, field emission scanning electron microscopy and electrical properties analyses were evaluated. X-ray diffraction of the powders calcined by the microwave process shows the formation of perovskite structure with orthorhombic geometry, but it is possible to observe the presence of other phases. The presence of the secondary phases found can have a great influence on the heating rate during the synthesis on which the kinetics of the reaction of formation of the piezoelectric compound depend. The calcined powder was sintered at different temperatures by conventional and non-conventional processes. The microstructure of the ceramics sintered by microwave at 1050 °C for 10 min shows perovskite cubes with regular geometry, of size close to 2–5 µm. However, the observed porosity (~8%), the presence of liquid phase and secondary phases in the microstructure of the microwave sintered materials lead to a decrease of the piezoelectric constant. The highest d₃₃ value of 146 pC/N was obtained for samples obtained by conventional at 1100 °C 2 h compared to samples sintered by microwave at 1050 °C 10 min (~15 pC/N).

【 授权许可】

Unknown