- S. M. Hassani-Gangaraj
Enhancement of hardness and corrosion resistance of aluminum alloys persist as an important challenge in order to increase the lifetime of industrial parts and accessories. This improvement of surface properties must be accomplished by low cost and minimum environmental impact processes. On these considerations, in the present work DC pulsed plasma nitriding at rough vacuum (1.9 torr) was carried out on 6061 aluminum alloy using different N2/Ar mixtures (100/0, 50/50 and 75/50) to sustain the DC glow discharge. Influence of gas mixture on surface morphology, hardness, phases composition and corrosion performance was evaluated through scanning electron microscopy, Vickers micro indentation, X-ray diffraction and potentiodynamic polarization curves (3.5% NaCl), respectively. For the better evaluated case (50N2/50Ar mixture), results show the increase in surface hardness from 113 to 148 HV0.025, and the decrease in the corrosion current value to an a half respect untreated sample. The increasing in hardness and corrosion performance of evaluated aluminum alloy was attributed to the chemical surface modification by formation of a thin layer constituted by cubic and hexagonal aluminum nitrides. Keywords— Aluminum 6061, corrosion resistance, hardness, plasma nitriding.