Development of novel metallic feedstock materials for heating elements produced by thermal spraying

热喷涂加热元件用新型金属原料的开发

• 批准号: 437095503
• 负责人: Professorin Dr.-Ing. Kirsten Bobzin
• 金额: --
• 依托单位: Institut für Oberflächentechnik (IOT)
• 依托单位国家: 德国
• 项目类别: Research Grants
• 财政年份: 2020
• 资助国家: 德国
• 起止时间: 2019-12-31 至 2022-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/437095503?language=en
• 关键词: Development; novel; metallic; feedstock; materials

Thermally sprayed coatings can be used as heating elements to increase the system efficiency and to miniaturize heating elements. An essential technical challenge for thermally sprayed heating elements is the limited lifetime due to local overheating caused by the heterogeneities of the coatings. For metallic materials High Entropy Alloys (HEA) exhibit a very high specific electric resistance and positive TCR-values as well. Considering these properties HEA alloys represent a suitable alternative as coating fulfilling the function as heating element. Up to now, this potential of HEA alloys has not been studied. This proposal aims for the development of novel metallic coatings as heating elements for potential applications up to T=350°C with prolonged lifetime. Novel feedstock materials will be designed and developed based on HEA alloys to achieve high specific electric resistance. The designed HEA alloys will be investigated with respect to their suitability for the aimed application. The metallic heating elements will be deposited using a fine powder fraction by means of high velocity thermal spray processes and plasma spraying to reduce the heterogeneities of the coatings. The improved heterogeneity of coating can reduce local overheating. In addition, the low coating thickness can improve the stress states in the coating systems. As result, the lifetime can be increased. In the first two research years, novel HEA alloys will be designed with respect to specific electric resistance and their thermal expansion coefficient. These designed alloys will be produced by melting processes. Subsequently, these samples will be characterized and investigated in terms of the microstructure, phase composition, phase stability, specific electric resistance, thermos-physical properties, mechanical properties and oxidation behavior. The two or three most promising alloys among them will be selected based on the results achieved in the first two research years. In the following project for the third research year, the heating elements by means of thermal spraying will be developed based on the selected HEA alloys. The influence of spray processes and parameters on the coating properties will be investigated. The coatings will be characterized regarding their microstructure, phase composition and electric conductivity. The lifetime of the coatings will be evaluated by means of cyclic heating tests and analyzed with respect to the failure mechanisms. In this way, the suitability of the novel heating elements will be qualified.

热喷涂的涂料可用作加热元素，以提高系统效率并微型加热元件。热喷涂加热元件的基本技术挑战是由于涂料的异质性引起的局部过热，寿命有限。对于金属材料，高熵合金（HEA）也具有很高的特异性电阻和阳性TCR值。考虑到这些特性，Heays代表合适的替代方案，因为将功能作为加热元件实现。到目前为止，Hea Alloys的这种潜力尚未研究。该提案旨在开发新型金属涂层，作为延长寿命的潜在应用的加热元素。新型原料材料将根据HEA合金设计和开发，以实现高特异性电阻。设计的HEA合金将进行研究。关于其适用于瞄准应用的适用性。金属加热元件将通过高速速度热喷雾过程和血浆喷雾来减少涂料的异质性，以细粉末分数沉积。涂料的异质性的改善可以减少局部过热。另外，低涂层厚度可以改善涂料系统中的应力状态。结果，可以增加寿命。在前两个研究年中，新型HEA合金将针对特定的电阻及其热膨胀系数进行设计。这些设计的合金将通过熔化过程产生。随后，这些样品将根据微结构，相组成，相位稳定性，特定电阻，热物质特性，机械性能和氧化行为来表征和研究。其中两个或三种最有前途的合金将根据前两个研究年份的结果选择。在第三个研究年的以下项目中，将根据所选的HEA合金开发逐热喷涂的加热元件。将研究喷雾过程和参数对涂料特性的影响。涂料的微观结构，相组成和电导率将表征。涂料的寿命将通过循环加热测试进行评估，并针对破坏机理进行分析。这样，新颖的加热元件的适用性将是合格的。