Damage study of cold-sprayed composite materials for application to electrical contacts
Résumé
This work demonstrated the feasibility of cold spray for the achievement of industrial electrical contacts to be used in contactors and circuit breakers. This resulted from the study of cold spray conditions when applied to two types of silver-based particulate composites. Starting materials, primarily powder characteristics and addition content, and spraying conditions were optimized from thorough studies of microstructures and mechanical properties of the cold-sprayed composites. These involve x-ray microtomography and transmission electron microscopy in particular, in addition to tensile tests. Moreover, thermomechanical laser testing of series of cold-sprayed microstructures was successfully developed to investigate into damage mechanisms in coatings. The whole led to a novel phenomenological approach to damage in cold-sprayed materials. Durability tests of the best coatings were carried out using industrial facilities. Cold-sprayed contacts compared more than well with those from conventional powder metallurgy (P/M), which opens a new and cost-attractive production route for electrical contacts.