Novel Piezoelectric Materials for Sonar Transducers

基于其他地方的最新发现，当氧化汞(HfO2)薄膜在一定的机械约束下结晶时，它们变成了压电材料，这个项目试图回答这样一个问题：是否可以制备出具有相同或相似压电晶体对称性的块体材料。这项研究将不限于对HfO2的简单修饰，还将考虑类型为AxB(1-x)O2的二元化合物。该项目将审查候选化合物的已知晶体结构，并与HfO2的压电型变体进行比较，并为这些结构制定一些简单的对称性存在准则，类似于钙钛矿的Goldschmidt容差因子。我们将试图通过固态化学方法对化合物的合成和结构分析来填补文献数据中的任何空白。基于从调查中得出的结构存在标准，确定潜在的压电变体，包括在候选化合物与HfO2或ZrO2之间形成固溶体。将制备这些化合物，并分析它们的结构随温度的变化。有希望的化合物将被烧结，并进行铁电性和压电性测试。得到的任何压电化合物的性能都将与现有材料进行比较，并评估其在声纳换能器和其他应用中的潜在用途。目前全球对无铅压电材料的研究主要集中在钙钛矿型，该项目有可能发现全新的非钙钛矿型无铅化合物，具有有用的压电性能，这可能有助于现有的GB 2000万年产量。市场：压电产品市场。

Based on the recent discovery elsewhere that when thin films of hafnium oxide (HfO2) are crystallized under certain mechanical constraints they become piezoelectric, this project seeks to answer the question whether bulk materials can be prepared with the same or similar piezoelectric crystal symmetry. The search will not be restricted to simple modifications of HfO2, but will also consider binary compounds of the type AxB(1-x)O2.The project will review the known crystal structures of the candidate compounds in comparison to the piezoelectric variant of HfO2 and formulate some simple symmetry existence criteria for these structures, similar to the Goldschmidt tolerance factor for perovskites. We will attempt to fill any gaps in the literature data through synthesis and structure analysis of the compounds by solid state chemical routes.Based on the structure existence criteria derived from the survey, a strategy to identify potential piezoelectric variants, including forming solid solutions between candidate compounds and HfO2 or ZrO2. These compounds will be prepared and their structures analysed as a function of temperature. Promising compounds will be sintered and tested for ferroelectricity and piezoelectricity. The properties of any resulting piezoelectric compounds will be compared to existing materials and assessed for potential use in sonar transducers and other applications.The current worldwide search for lead-free piezoelectric materials has focussed on perovskites, this project has the potential to identify completely new non-perovskite, lead-free compounds with useful piezoelectric properties that may contribute to the existing £20 million p.a. market piezoelectric product market.