Effect of Nb content on microstructure, corrosion and tribology properties of AlCrTiV high entropy alloy films

The (AlCrTiV)_1-xNb_x HEAF with varying Nb contents were prepared using a co-sputtering method that combined DC magnetron (constant power) and RF magnetron (variable power). This study primarily investigated the effects of different Nb contents on the microstructure, corrosion properties, and friction properties of the films. The results indicated that the films with varying Nb contents exhibited an amorphous structure characterized by a dense surface and uniform elemental distribution. As the Nb content increased, the cross-section displayed a columnar amorphous structure, while the surface roughness of the films initially decreased before increasing with the changing Nb content. The corrosion resistance of the thin film initially increases and then decreases with variations in Nb content, with the sample exhibiting optimal corrosion resistance at the Nb content of 32.1 %. The primary form of corrosion for the thin film is pitting, and passivation occurs on the film surface during the corrosion process. The Nb element influences the corrosion resistance of the thin film by altering the interaction mode of the O element. While the Nb content does not affect the friction coefficient of the thin film, the bonding force between the film and the substrate decreases with the addition of Nb, resulting in the film being worn through during the friction process. This may be attributed to changes in the deposition mode of the thin film caused by the introduction of RF sputtering, which leads to a decrease in the cohesion of the thin film.