“…However, when studied under the same annealing conditions, steel was found to suffer minimal reduction in microhardness, suggesting that replacing copper with steel as the substrate could solve this problem. The adhesion of the coating was measured to be around 15 MPa both before and after annealing, smaller than that of VPS-W coatings reported in the literature [12][13][14]. This is most likely due to smaller particle size, which means lower kinetic energy and higher residual stress [6].…”