Supersonically Sprayed Copper–Nickel Microparticles as Flexible and Printable Thin-Film High-Temperature Heaters

Cu and Ni nanoparticles are sprayed at supersonic velocities onto stiff glass, ceramic, and marble surfaces, as well as onto flexible polymer substrates of complex shapes. Joule heating occurs when a voltage is applied to the sprayed Cu–Ni thin films, enabling their use as thin-film heaters. The Cu–Ni composition is varied to control the electrical and the thermal properties of the films, which affects the total amount of power used for the heating. At a high Cu content, the temperature reaches as high as 1000 °C, which significantly broadens the range of potential applications of such film heaters. The thermal stability of the film heaters is confirmed by cyclic testing, which shows repeatable rapid undulations in the temperature range of 600 °C. The Cu–Ni film heaters can be printed on any type of substrates including mirrors, glasses, and flexible polymers, and the method of film fabrication is rapid and scalable. The surface temperature of the heater is measured experimentally and matches well with the theoretical predictions. The Cu–Ni film heaters find applications in vehicle defrosters, smart heat-retaining windows, domestic appliances, etc., and industrial heating and defrosting of complex surfaces.