Abstract

COUPERTHWAITE, R.A.; CORNISH, L.A.  and  MWAMBA, I.A.. Cold-spray coating of an Fe-40 at.% Al alloy with additions of ruthenium. J. S. Afr. Inst. Min. Metall. [online]. 2016, vol.116, n.10, pp.927-934. ISSN 2411-9717.  http://dx.doi.org/10.17159/2411-9717/2016/v116n10a6.

In previous work by the authors, it was established that additions of 0.2 at.% Ru to an Fe-40 at.% Al alloy improved the corrosion and oxidation resistance of the alloy. The alloy was produced by mechanical alloying and spark plasma sintering and the work showed that non-equilibrium processing was able to significantly refine the grain size of the material. The sintered material had a higher hardness than the as-cast material and the change in grain size did not significantly affect the oxidation and corrosion. In the present research, the mechanically alloyed powder was coated onto a mild steel substrate using cold-spray coating at a gas pressure of 10 bar and a temperature of 500°C. The coatings were found to be 5-10 μm thick, although thicknesses of up to 30 μm were observed. The coated materials were subjected to oxidation and corrosion tests to determine the effectiveness of the coating in increasing the oxidation and corrosion resistance of mild steel. This was done to determine the effectiveness of cold-spray coating as a technique to coat these mechanically alloyed powders.

Keywords : Fe-Al alloy; mechanical alloying; cold-spray coating; addition; corrosion resistance.

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