Laser surface treatment of aluminium 6013/SiCp composite for corrosion resistance enhancement

A 2-kW continuous wave Nd:YAG laser has been used to modify the surface mic rostructure of an Al-6013/SiCp, composite; the aim is to improve the corros ion resistance of the material. Laser surface treatment of the composite at laser intensities of 6.37 and 10.62 J mm(-2) has resulted in selective vap orization of the aluminium matrix. Moreover, the amount of Mg2Si precipitat es in the surface of the composite was reduced. The results of both of the anodic potentiodynamic polarization and immersion tests have shown that the pitting resistance of the composite was significantly improved by the lase r surface treatment. An increase in E-corr and E-pit of up to 230 and 60 mV , respectively, was obtained after laser surface treatment. Furthermore, th e size and the amount of corrosion pits were considerably reduced. The impr ovement was considered primarily due to the reduction and refinement of Mg2 Si precipitates in the surface of the composite, which were found to be sit es for pit nucleation. (C) 1999 Elsevier Science S.A. All rights reserved.