Influence of Powder Characteristics on the Microstructure and Bond Strength of Cold-Sprayed Aluminum Coating

This study assesses the influence of powder morphology on the microstructure and bond strength of cold-sprayed aluminum. Aluminum powders with spherical and irregular particle shapes were deposited on shot-peened steel. The feedstocks were mixed with alumina powders, either spherical or angular in shape, to improve coating properties. Coating samples and powder mixtures were examined by means of SEM and XRD analysis and pull-off tests were conducted to evaluate coating adhesion. It was found that alumina addition reduces porosity and increases hardness and that aluminum-alumina mixtures with the same particle shape are more suitable for producing dense coatings with high bond strength.