Novel materials for thermally sprayed electric heaters

Thermal spray technology is used on an industrial scale to produce electric heaters by stacking electrically insulating and conductive layers on top of each other. The main advantages of this manufacturing process are the high process efficiency and productivity, the use of common thermal spray feedstock materials and the high-power density that can be reached with these heaters compared to competing PTC or wire-based technologies. Ni 20Cr is the most common material for the heater circuit.

For novel designs or higher power levels alloys with higher specific resistivity and tailored TCR response than Ni 20Cr are of interest. Höganäs has developed two FeCr-based alloys that cover wide spectrum in their electric properties. One material shows a high TCR value offering additional safety in the operation by reducing the risk of thermal run-off and allows an indirect measurement of the component temperature. The other material with a TCR value way below 100 ppm over a temperature range up to 700 °C is intended for high-temperature applications allowing stable and linear power regulation. In addition these FeCr-based alloys avoid the use of precious nickel and are a more sustainable alternative.