CARACTERIZACIÓN TRIBOLÓGICA DE PELÍCULAS DE Cr/CrN DEPOSITADAS SOBRE ACERO RUS-3 POR EL MÉTODO DE PULVERIZACION CATODICA D.C, ASISTIDA POR CAMPO MAGNETICO

Abstract

Cr/CrN films were deposited onto silicon [100] and RUS-3 steel substrates by d.c reactive cathodic sputtering magnetic field assisted technique, using a chromium target (99.95 %). In order to study the effect of the nitrogen content in the gas Ar/N2 mixture on the tribological properties of the steel coated with Cr/CrN bilayer system, various nitrogen concentrations (10, 20, and 40%) were used. XRD patterns of Cr/CrN films exhibited the [111] [200] and [220] reflection planes related to the Cr2N cubic phase, as well as a reflection [200] related to the β-Cr2N hexagonal phase. On the other hand, FTIR analysis showed the presence of active modes between 350 cm-1 and 600 cm-1 centered at 520 cm-1, corresponding to the Cr-N chromium nitride bonds, the morphology of the films was evaluated by atomic force microscopy. The tribological properties of Cr/CrN films were studied by pin-on-disc test, finding a direct relation between the decrease of friction coefficient values by 25%, as function of the decrease in N2 content in the gas mixture. The wear tracks were studied by optical microscopy and profilometry, the contact area in the balls was studied by scanning electron microscopy and the adherence of Cr/CrN films by scratch test.