基于相对法理论的陶瓷涂层常温与高温力学性能评价

Ceramic coatings, such as thermal barrier coating, wear-resistance coating and anti-corrosion coatings, are more and more widely used in modern industry. Since most brittle coatings are tightly bonded on substrates and hardly separated from the substrates, the mechanical properties of the coating on substrate are difficult to measure like monolithic materials. Except to hardness measurement, there is no mechanical property test available for ceramic coating.Over the years, the fast development of ceramic coatings yields great requirement for new approaches to measure mechanical properties of the coating. A new technique called relative method and related calculation model were proposed in this project to evaluate elastic modulus and strength of ceramic coatings through indirect approach, and further expand to high temperature testing environment as well asthe modulus of each layer in multilayer coatings. The key of this method is to establish the theoretical relationship among the properties of coating and properties of coating/substrate system and substrate properties. The properties of ceramic coating can be obtained simply by testing the substrate and coated sample. By this way, the elastic modulus, strength and interfacial bond strength of ceramic coatings are determined by impulse excitation technique, three point bending and cross-bonded method. Those methods never used for coatings properties before. The aim of this work is trying to end the history in which the properties of ceramic coatings hardly be tested, and to establish the evaluation methodology and standardization of mechanical properties of ceramic coatings.

陶瓷涂层(如热障涂层、防腐涂层、耐磨涂层等）是不能从基体上分离出来进行测试的, 因此其力学性能的评价除硬度之外几乎没有测试方法和检测技术，只有越来越紧迫的需求。针对这种重要需求和关键问题，本项目提出相对法评价技术和计算模型，通过间接测试的方法获得陶瓷涂层的弹性模量和强度数据，并进一步推广到高温环境下的涂层性能测试以及多层复合涂层的各层模量的评价。其核心是在理论上建立涂层材料与基体材料和复合材料性能之关系，从而可以用基体和复合材料的测试数据算出涂层材料的性能。实验上则采用常规的激励法、弯曲法和十字交叉法等标准化技术来获得以往无法测得的涂层材料的弹性模量和强度以及涂层界面结合强度等性能，为陶瓷涂层材料的设计和可靠性评价提供有效手段。目标是要尽快结束陶瓷涂层材料的力学性能无法测试的历史，建立陶瓷涂层的常温弹性模量、断裂强度以及界面结合强度的评价方法并在国内外标准化。

随着科学技术的发展，工程设备及构件的工作条件日益苛刻，对工程材料表面性能要求也越来越多高，单一材料很难满足工程需求。而涂层技术作为一种重要的现代表面处理技术和材料复合技术，涂层与基体形成的复合体可使它们在性能上取长补短，极大的提高了材料的适用范围。在众多涂层材料中，陶瓷涂层因具有耐高温、耐磨损、耐腐蚀等优异特性，广泛地应用于石油化工、国防军工、航天航空、机械电子等领域。然而陶瓷涂层由于难以从基体上分离出来进行单独测试，因此其力学性能的评价除硬度之外在国内外几乎没有测试方法和检测技术，只有越来越紧迫的需求。本项目针对涂层性能表征这一国际性难题，提出相对法测试技术和计算模型，通过间接测试的方法获得陶瓷涂层的弹性模量和强度等性能，并进一步推广到高温环境下的涂层性能测试、多层复合涂层的各层模量测试。另一方面，基于相对法技术，建立了陶瓷涂层的界面结合强度、密度、热膨胀系数以及残余应力等性能的测试方法，并将测试方法转化为国际标准在国内外推广应用，为陶瓷涂层材料的设计和可靠性评价提供了有效手段。