Innovative method of pulverisation coating of prestabilized nanopowders for mass production of gas sensors

A method to coat thin layers of previously stabilised sensing material by pulverisation is presented. Parameters such as pulverisation timing, substrate temperature and flow of pulverised material are controlled by computer and their influence over final layer is explained. SEM characterisation was performed on samples which showed fine homogeneity and good control of thickness, ranging from 0.2 to 10 μm. Different coatings of SnO2 and other semiconductor sensing materials were performed over glass, alumina and silicon substrates. Interdigitated sensors were coated with SnO2 and a good sensitivity to CO, CH4 and NO2 was found. The method is suitable for any gas sensors based on nanopowders, either for laboratory sample evaluation or mass production using standard substrates or micromachined sensors.