Asurface hardening process based on Ni coating and subsequent diffusion heat treatments was studiedfor Al7075 alloy. Nickel coatings with different thickness on 7075 Al alloy were obtained by electrolyticand electroless processes . Heat treatments in inert atmosphere at 500 °C and 530 °C for different timeswere performed in order to obtain surface hardening of the aluminum alloy by diffusion of Ni into thesubstrate. The effect of temperature and time on the depth of hardening was studied by SEM, EDS, Glowdischarge optical spectrometry, microhardness tests and tribological tests.Surface hardness higher than 1000 HV and depth of hardening higher than 100 mm were achieved bydiffusion of Ni layers and formation of Al3Ni2 and Al3Ni intermetallic phases .The tribological test on Al7075 alloy against a hard Cr coated steel cylinder in air showed an averagecoefficient of friction ? of about 0.5 with a wide variation range, while all the coated and treated samplesexhibited a coefficient friction of about 0.7. However, the wear scar depth of the hardened alloy is about30 times lower than that of the Al 7075 alloy