Abstract

SILVA, Katherine  and  STAIA, Mariana. Characterization and wear behavior of a 7075-t6 aluminum alloy coated with electroless ni-p. Rev. Fac. Ing. UCV [online]. 2008, vol.23, n.4, pp.37-45. ISSN 0798-4065.

The present work evaluates the dry sliding wear performance of a 7075-T6 aluminum alloy autocatalytically coated with electroless Ni-P. Characteristics such as coating morphology, compositional variation of the coating through its thickness, as well as coating microhardness were reported. The wear tests were carried out in a tribometer, under ball-on-disc configuration, and balls of AISI 52100 steel of 6mm diameter were employed as a static counterpart. A normal load of 5N was applied for all the tests which were carried out at three different sliding velocities (0.005, 0.1 and 0.15 m/s) for 1000 m sliding distance. When the tests were conducted at low sliding velocity (0.05 m/s), a severe adhesive wear mechanism, characterized by plastic deformation and transference of the coating to the steel ball, was found for the aluminum alloy disc coated with electroless Ni-P/AISI 52100 ball tribological pair. A three body abrasive wear mechanism was present when using higher sliding velocity. It was determined that, for the lowest sliding velocity employed in this study, the wear constant value for the coated system was 77% smaller than the value corresponding to the uncoated alloy. However, for all the tested conditions, the value of the wear constant was of approximately 10-4 mm3N-1m-1, indicating that both coated and uncoated aluminum alloy presented a low tribological performance under sliding conditions.

Keywords : Electroless Ni-P; Aluminium alloy 7075-T6; Sliding wear.