As the reports in the literature regarding corrosion performance of Al/TiB2 MMC are rather contradictory, the optimization of laser surface alloying parameters for these composite coatings seems to be necessary. The characterization of the MMC was carried out by optical microscopy (OM), scanning electron microscopy (SEM/EDS) and x-ray diffraction (XRD). Partial melting of the alloying powder occurred and the chemical reactions with the a-Al in the matrix led to the formation of AlTi and AlB2 phases. Eutectics of TiB2/Al and TiB2/Ti were observed. The results of the tests indicate that TiB2 reinforcement does not give significant increase in microhardness of aluminium. The corrosion resistance of a single laser trackline MMC in a 3.65 % NaCl solution was improved, especially for the sample produced at high scan speed, with the lowest volume fraction of TiB2 particles.
Reference:
Popoola, PAI, Pityana, SL, Fedotova, T and Popoola, OM. 2011. Nd: YAG laser treatment of aluminium-TiB2 coated: optimization of corrosion properties. Materials Science: Poland, vol. 29(2), pp 92-104
Popoola, P., Pityana, S. L., Fedotova, T., & Popoola, O. (2011). Nd: YAG laser treatment of aluminium-TiB2 coated: optimization of corrosion properties. http://hdl.handle.net/10204/5779
Popoola, PAI, Sisa L Pityana, T Fedotova, and OM Popoola "Nd: YAG laser treatment of aluminium-TiB2 coated: optimization of corrosion properties." (2011) http://hdl.handle.net/10204/5779
Popoola P, Pityana SL, Fedotova T, Popoola O. Nd: YAG laser treatment of aluminium-TiB2 coated: optimization of corrosion properties. 2011; http://hdl.handle.net/10204/5779.