Cold Spraying Combined to Laser Surface Pre-Treatment Using PROTAL®

The effect of pre-treatment of the substrate on Cold Spray coating was studied. A fine aluminum powder [17-35 μm] was cold sprayed onto AISI 2017 aluminum-based alloy with different preparations. In addition to as-received substrates, a first series of substrates were prepared by conventional methods: i.e. polishing, grit-blasting. Others were pre-treated using a pulsed Nd-YAG laser in the PROTAL^® process. In the PROTAL^® device the laser head was coupled with the cold spray gun to result in laser passing just prior to cold spray deposition. A beneficial effect of laser pre-treating on particle-substrate adhesion was shown. To elucidate the main interaction mechanisms, coating-substrate interfaces were studied with Scanning Electron Microscopy (SEM) and Transmission Electron Microscopy (TEM) of thin foils which were prepared using Focused Ion Beam (FIB). These mechanisms are discussed in the light of results from LAser Shock Adhesion Test (LASAT) of cold-sprayed coatings.