Department of Materials and Ceramic Engineering, CICECO, Aveiro Institute of Materials, University of Aveiro , 3810-193 Aveiro, Portugal.
Science of Ceramic Processing and Surface Treatments, University of Limoges , 87060 Limoges, France.
Langmuir. 2016 May 31;32(21):5241-9. doi: 10.1021/acs.langmuir.6b00669. Epub 2016 May 17.
A current challenge for the fabrication of functional oxide-based devices is related with the need of environmental and sustainable materials and processes. By considering both lead-free ferroelectrics of potassium sodium niobate (K0.5Na0.5NbO3, KNN) and aqueous-based electrophoretic deposition here we demonstrate that an eco-friendly aqueous solution-based process can be used to produce KNN thick coatings with improved electromechanical performance. KNN thick films on platinum substrates with thickness varying between 10 and 15 μm have a dielectric permittivity of 495, dielectric losses of 0.08 at 1 MHz, and a piezoelectric coefficient d33 of ∼70 pC/N. At TC these films display a relative permittivity of 2166 and loss tangent of 0.11 at 1 MHz. A comparison of the physical properties between these films and their bulk ceramics counterparts demonstrates the impact of the aqueous-based electrophoretic deposition (EPD) technique for the preparation of lead-free ferroelectric thick films. This opens the door to the possible development of high-performance, lead-free piezoelectric thick films by a sustainable low-cost process, expanding the applicability of lead-free piezoelectrics.
目前，制造基于功能氧化物的器件面临的一个挑战与环境和可持续材料及工艺的需求有关。考虑到无铅铁电体钾钠铌酸盐（K0.5Na0.5NbO3，KNN）和水基电泳沉积，我们在这里证明，环保的水性溶液处理工艺可用于生产具有改进的机电性能的 KNN 厚膜涂层。在铂基底上制备的厚度在 10 到 15 μm 之间的 KNN 厚膜，介电常数为 495，1 MHz 时介电损耗为 0.08，压电系数 d33 约为 70 pC/N。在居里温度下，这些薄膜的相对介电常数为 2166，1 MHz 时损耗角正切为 0.11。这些薄膜的物理性能与块状陶瓷相比表明，水基电泳沉积（EPD）技术在制备无铅铁电体厚膜方面的重要性。这为通过可持续的低成本工艺开发高性能、无铅压电厚膜开辟了道路，扩大了无铅压电体的适用性。
