Laser surface treatment of aluminium 6013/SiC_pcomposite for corrosion resistance enhancement

A 2-kW continuous wave Nd:YAG laser has been used to modify the surface microstructure of an Al-6013/SiCpcomposite; the aim is to improve the corrosion resistance of the material. Laser surface treatment of the composite at laser intensities of 6.37 and 10.62Jmm-2has resulted in selective vaporization of the aluminium matrix. Moreover, the amount of Mg2Si precipitates 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 laser surface treatment. An increase in Ecorrand Epitof up to 230 and 60mV, respectively, was obtained after laser surface treatment. Furthermore, the size and the amount of corrosion pits were considerably reduced. The improvement was considered primarily due to the reduction and refinement of Mg2Si precipitates in the surface of the composite, which were found to be sites for pit nucleation.