Preparation And Characteristics Of Multi-component (AlCrWTaTiNb)C_xN_y Composite Films

Since a new design idea of so-called multiple high entropy alloys (HEAs) was proposed by Yeh et al, some scholars begin to study multi-component carbonitride films. These films have not only a very low friction coefficient, but also high hardness because carbon-carbon covalent bond, large lattice mismatch between carbides and nitrides, and graphite phase exist in the films. The composite that contains amorphous carbon (a-C) has a higher hardness and lower friction coefficient, thus, the multi-component carbonitride films with amorphous carbon could form a new coating with more excellent performance. In the high-speed machining or dry friction process, as known to all, the low friction coefficient has a direct benefit of reducing the contact temperature of friction counterparts and high hardness can significantly improve the wear resistance of coatings. Therefore, films with both high hardness and self-lubricating characteristic are important for protective coatings to increase the performance and service life of cutting tools.In this paper, multi-component (AlCrWTaTiNb)CxNy films were prepared using a multiple target magnetron sputtering technique. We have not only investigated the chemical composition, microstructure, surface morphology, mechanical properties and electrochemical performance under different carbon target power, substrate temperature, the flow ratio of N2, but also compared the difference of (AlCrWTaTiNb)Nx, (AlCrWTaTiNb)Cx and (AlCrWTaTiNb)CxNy in this aspects. The following conclusions are obtained:1. (AlCrWTaTiNb)CxNy films without carbon are two-phase FCC solid solution structure with a (220)-preferred orientation and present a triangular morphology. When the carbon target power is in the range of 50-150 W, (AlCrWTaTiNb)CxNy composited films show a single-phase FCC solid solution structure with a (111)-preferred orientation and consist of ball-like particles. The composited films deposited at the carbon target power of 100W exhibit the best performances. The micro-hardness and elastic modulus are 23 GPa and 290 GPa, respectively. A corresponding H3/E2 value that reflected film frictional characteristics also reaches a maximum of 0.147.2. Substrate temperature has no effect on the crystal structure and surface morphology of (AlCrWTaTiNb)CxNy composite films. As the substrate temperature increases, grain size first decreases and then increases. When the substrate temperature is 200?, the peak micro-hardness and elastic modulus of films reach 17.3 GPa and 240 GPa, respectively.3. With the increase of RN, the deposition rate of (AlCrWTaTiNb)CxNy composite films first increases then decreases. When the RN increases from 0 to 30%, the surface morphology of the (AlCrWTaTiNb)CxNy films takes place an interesting transformation, from the spherical particles into worm-like, then from the worm-like particles into a triangular shape, finally back into the spherical particles.4. Compared the difference of (AlCrWTaTiNb)Ny, (AlCrWTaTiNb)Cx and (AlCrWTaTiNb)CxNy films, the hardness and elastic modulus of the (AlCrWTaTiNb)CxNy film are maximum, corrosion current density is minimum, and polarization resistance is the largest, so mechanical properties and corrosion resistance are superior to other two kinds of films.