Microstructures and mechanical properties of TiCrN/AlTiCr based coatings prepared by plasma nitriding 5083 Al alloys co-deposited with TiCr films

A duplex treatment involving sputtering TiCr film followed with plasma nitriding was employed to in-situ fabricate multilayer coatings on the surface of 5083 Al alloys. TiCr films with different Cr addition were firstly sputtered on 5083 Al alloys by using magnetron sputtering, then nitrided at 460 °C under the N2H2 gas condition. Results showed that the as-obtained coatings were composed of the outside (Ti, Cr)N0.3 or (Ti,Cr)N layer and the inside Al18(Ti,Cr)2Mg3 layer. With increasing Cr content in the TiCr film, (Ti,Cr)N phase was inclined to form in the outside layer and the Al18(Ti,Cr)2Mg3 layer increased the thickness. Meanwhile, the surface hardness of multilayer coatings was enhanced and reached the maximum value of ∼1020 HV. Specimens with outside (Ti,Cr)N layer showed better wear resistance than specimens with outside (Ti,Cr)N0.3 layer. The nitrided specimens exhibited mainly adhesive wear and abrasive wear accompanied with oxidation wear.