Development of thermoelectrically active and thermally sprayed ceramics

经济型热电发电机（TEG）的制造需要有效的生产技术。热喷涂技术有可能成为生产teg的一种经济有效的替代方案，但必须解决主要的机械和技术挑战。TEG可以通过热喷涂作为由热电活性p和n半导体以及电绝缘和导电材料组成的多层系统来实现。喷淋材料的性能不仅与喷淋工艺有关，还与原料的质量有关。在热喷涂中，电绝缘或导电材料是众所周知的，而热电活性材料的研究却很少。开发高性价比的TE材料是teg生产的迫切需要。特别是对于热喷涂的加工，除了通常要求的电导率和导热性以及塞贝克系数外，热电材料还应该是可喷涂的，具有低毒性并且可以大量使用。氧化物材料在满足这些要求方面具有最高的潜力。然而，为了了解这些材料在喷涂过程中的具体材料行为并提高其ZT值，需要付出巨大的努力。因此，本项目的重点在于开发环境友好且经济可行的热电材料，可通过热喷涂进行加工。掺杂氧化锌由于具有良好的喷涂性能和热电性能，是最合适的氧化物材料之一。项目的主要目标是生产热电的活跃的涂料机械稳定,500µm厚,和现在至少0.3的ZT型温度高达600°c,为了这个目的,一个定制的喷雾原料,粉末的形式和悬浮液,开发和制造,工艺参数之间的关系的不同热喷涂方法和涂料性能(热电、结构、物理)研究。

The manufacture of economical thermoelectric generators (TEG) requires effective production technologies. Thermal spraying has the potential to be a cost-effective alternative for the production of TEGs, but major mechanical and technological challenges have to be addressed. TEG's can be realized by thermal spraying as a multi-layer system consisting of the thermoelectrically active p and n semiconductors, as well as electrically insulating and electrically conductive materials. The properties of the sprayed materials depend not only on the spray process but also on the quality of the feedstock material. While electrically insulating or conductive materials are well known in thermal spraying, thermoelectrically active materials have rarely been studied. The development of cost-effective TE materials is an urgent need for the production of TEGs. In particular for the processing by thermal spraying, in addition to the usual requirements concerning electrical and thermal conductivity and the Seebeck coefficient, the thermoelectric material should also be sprayable, have a low toxicity and be available in high amounts. Oxide materials have the highest potential to fulfill there requirements. However significant effort is required in order to understand the specific material behavior of these materials during the spray process and to improve their ZT values. Therefore, the focus of this project lies in the development of environmentally friendly and economically viable thermoelectric materials, which can be processed by thermal spraying. Doped zinc oxide is, due to its sprayability and promising thermoelectric properties, one of the most suitable oxide materials. The main goal of the project is the production of thermoelectrically active coatings which are mechanically stable, ca. 500 µm thick, and present a ZT of at least 0.3 at temperatures above 600 ° C. For this purpose, a tailored spray feedstock, in the form of powders and suspensions, has to be developed and manufactured, and the relationship between the process parameters of the different thermal spray methods and the coatings properties (Thermoelectric, structural, physical) has to be studied.