Besides conventional industrial demands, thermally sprayed coatings are increasingly used for innovative products. Such an application is the additive manufacturing of electrical components in automotive engineering. In particular, heating units are currently manufactured by a combination of various spray technologies. At present, simpler spraying processes like flame spraying are investigated with regard to their suitability as a future cost-effective alternative for fabricating isolating alumina coatings. In the present study, alumina cords were flame-sprayed using compressed air and argon as atomizing gases. The results demonstrate finely dispersed microstructures and a more regular and partially even higher surface and volume resistivity compared to past investigations in the literature as well as conventionally plasma-sprayed coatings despite a significantly reduced coating thickness. The content of alpha phase is clearly higher than for plasma-sprayed coatings, regardless of the atomizing gas used. Moreover, flame-sprayed coatings using argon reveal a higher resistivity in comparison to coatings sprayed with air. While the atomizing gas is found to mainly influence the ideal stand-off distance, the phase composition is not changed severely. In addition to the phase composition and kinematics, it can finally be concluded that humidity plays a major role in the coating properties.

除了传统的工业需求外，热喷涂涂层越来越多地用于创新产品。这样的应用就是汽车工程中电气元件的增材制造。特别地，加热单元目前是通过各种喷涂技术的组合来制造的。目前，人们对火焰喷涂等更简单的喷涂工艺作为未来制造隔离氧化铝涂层的经济有效替代方案的适用性进行了研究。在本研究中，使用压缩空气和氩气作为雾化气体对氧化铝线进行火焰喷涂。结果表明，与文献中过去的研究以及传统的等离子喷涂涂层相比，尽管涂层厚度显着减小，但其微观结构更加分散，表面电阻率和体积电阻率更加规则，部分甚至更高。无论使用何种雾化气体，α相的含量明显高于等离子喷涂涂层。此外，与空气喷涂的涂层相比，使用氩气的火焰喷涂涂层显示出更高的电阻率。虽然发现雾化气体主要影响理想的隔离距离，但相组成并未发生严重变化。除了相组成和运动学之外，最终可以得出结论，湿度对涂层性能起着重要作用。