Mechanical and corrosive characteristics of Ta/TaN multilayer coatings

Ta/TaN multilayer coatings were prepared on Cr12MoV substrates by reactive magnetron sputtering combined with ion implantation. To achieve some information on the thickness and the interface of the coating, the cross-sections of the samples were observed by scanning electronic microscopy (SEM). The mechanical properties were evaluated using micro-indenter, micro-scratch and frictional wear testers and the corrosive behaviour was studied in aerated 3.5 wt.% NaCl aqueous solutions using an electrochemical work station. The mechanical and corrosive properties of the Ta/TaN multilayer coating were compared with TaN monolayer coating. The results showed that the Ta/TaN multilayer prepared by reactive magnetron sputtering combined with ion implantation exhibited high adhesion (about 50 N), excellent wear resistance and better corrosion resistance. The Ta/TaN multilayer was applied in a fuel pump accessory and the trial run test showed the service life of the part increased 5 times. It has been proved that ion implantation played an important role in enhancing adhesion and selection of appropriate modulation periods and layers improved the mechanical and corrosive properties.