Study On Preparation And Properties Of Cr/CrN Films By Magnetron Sputtering At Low Temperature

Hydraulic technology was indispensable for machinery manufacturing industry in recent years,especially utilized for manufacturing high precision components.However,the high-precision hydraulic parts always suffered from serious surface damage and even failure when serving at harsh conditions.In order to protect the parts,physical vapor deposition?PVD?technology as one type of green surface modification was carried out.This technique with low processing temperature provided an innovative routine against serious deformation and failure by preparing hard thin films,which possessed high hardness,low friction coefficient and excellent corrosion resistance.In this paper,CrN and Cr/CrN multilayer films were deposited on the tempered GCr15 substrate using DC magnetron sputtering technique at low temperature.Their mechanical properties,tribological performance,and corrosion behaviors were investigated systematically,and the corresponding results were as-following:?1?The deposition pressure had a great influence on the surface quality and mechanical properties of the CrN film.Under different working pressures?0.1⁰.8 Pa?,the phase structure of as-deposited CrN films was mainly composed of CrN,Cr₂N and Cr phases.The film prepared at a pressure of 0.1 Pa was the smoothest one with roughness Sa of 12.0 nm.The film microhardness reached a maximum value of 1700 HK_0.1,and exhibited good corrosion resistance.?2?The effect of substrate bias on the structure and properties of CrN films was investigated.As increasing of the substrate bias?-50^-200 V?,the film thickness was increased first and then decreased,and the microhardness of CrN film increased gradually.When the substrate bias was-200 V,the microhardness of the film reached 1620 HK_0.1,and the self-corrosion current density was as low as 3.150×10^-77 A·cm^-2.and The as-deposited films showed good bonding force,and the film prepared under high bias exhibited a low coefficient of friction of about 0.6.?3?The Cr/CrN multilayer films were prepared with different layer thickness ratios.The microhardness of the films increased from 1201.5 HK_0.1.1 to 1328.6 HK_0.1.1 with the decreasing of Cr/CrN layer thickness ratios.The friction coefficient of the films has no obvious difference,but the corrosion resistance increased with the decrease of the layer thickness ratio.?4?The effect of cycle period on the properties of Cr/CrN multilayer films was investigated.As the cycle period increased,the film hardness gradually increased to 1481.2HK_0.1,due to the increase in the number of multi-layer interfaced.The corrosion resistance of Cr/CrN multilayer films increased with increasing of cycle period.The multilayer film with a cycle period of 8 has the lowest current corrosion density of 2.64×10^-77 A·cm^-2,and exhibited the best protection for the substrate.