Use of Alternative Process Gases and Modifications for Manufacturing Heating Elements by Arc Spraying

In addition to conventional applications, thermally sprayed coatings or coating composites are increasingly used in the electronics industry, e.g. in integrated circuits. Another new field of application is the additive production of electrical components in automotive engineering by thermal spraying. In particular, heating elements are manufactured by a combination of various spray processes. At present, simpler spraying processes such as arc spraying are being investigated with regard to their technological suitability as a cost-effective alternative to plasma spraying in the manufacturing process of these components.

Previous own works and further literature revealed that coatings sprayed with a mixture of nitrogen and hydrogen show superior coating qualities with respect to oxidation and electrical conductivity. Thus, several mixtures and combinations of those gases and further process modifications were used in this study to produce arc-sprayed coatings, based upon a NiCr alloy, suitable as heating elements.

The results demonstrate strongly reduced oxide contents and improved morphologies of the coatings compared to the plasma-sprayed reference. This positively affects the specific conductivity of the coatings, the temperature coefficient of resistance and workability in the following structuring process.