Abstract
Coating build-up mechanisms and properties of cold sprayed aluminum-alumina cermets were investigated. Two spherical aluminum powders having average diameters of 36 and 81 microns were compared. Those powders were blended with alumina at several concentrations. Coatings were produced using a commercial low pressure cold spray system. Powders and coatings were characterized by electronic microscopy and microhardness measurements. In-flight particle velocities were monitored for all powders. The deposition efficiency was measured for all experimental conditions. Coating performance and properties were investigated by performing bond strength test, abrasion test and corrosion tests, namely, salt spray and alternated immersion in salt water tests. These coating properties were correlated to the alumina fraction either in the starting powder or in the coating.
