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.

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Laser material processing is a very rapidly advancing technology for various industrial applications, because of its many advantages. A few of its major advantages, less yet better controlled heat input, have been successfully exploited for the very critical application of aluminum alloy welding. This study suggested the source of weld-defects and its solution methods in welding a lithium ion battery with pulsed Nd:YAG laser. In the experiment, battery case has changed over joint geometry from side welding to flat welding. In the case of an electrolyte inlet seal welding, welding was carried out after pressing an Al ball and the degree of eccentricity, the contact length and the gap are presented as major parameters. With the Al ball indent improvement, the eccentricity and the gap were reduced and the contact length was increased. As a result of an experiment, a sound weld bead shape and crack-free weld bead were obtained.