Scratch Properties of Nb Ion-Implanted WC-Ni Cold Sprayed Coatings

The effect of niobium ion implantation on the surface and scratch properties of a WC-5wt.%Ni cold sprayed coating was investigated with accelerating energies of 60 and 170 keV and fluences of 5 × 10¹⁶ and 8 × 10¹⁶ ions cm⁻², respectively. High-resolution Rutherford backscattering spectroscopy spectra revealed that Ni-Nb and WC-Nb amorphous layers had likely formed. Using ion implantation parameters of 60 keV with a fluence of 8 × 10¹⁶ ions cm^-2 (coating 608-NB), higher Nb peak intensities were found. Oxide formation in the form of NbO, NbO₂, and Nb₂O₅ was detected with high-resolution x-ray photoelectron spectroscopy spectra analyses on the 608-NB coating, in conjunction with the intermetallic, thereby having the best coating properties: higher hardness, low roughness, and scratch properties compared to the other ion-doped samples. The failure mechanisms of all the coatings were found to be similar, showing angular cracks, cone cracking, and primary delamination.