A number of Al-, Mg- and Ti-base alloys were preconditioned by oxidation via Plasma-electrolytic oxidation (PEO) followed by the addition of Cr and Ni elements in the coating pores by chemical precipitation and a final stage of mechanical treatment. The overall effect was a combination of hardness and resistance to wear. PEO voltage level was found to be a factor decisive for the oxide layer thickness and level of porosity. In turn the latter two factors appeared to act upon the degree of hardening corundum to alumina fraction in the layer and the degree of Cr/Ni penetration into the oxide layer itself. The optimum condition of increased micro-hardness and high resistance to wear was achieved for an AlCu4Mg2 alloy of extended oxide layer thickness and intermediate levels of open porosity. Similarly good wear results were obtained for a Be60AlMg2 alloy of particularly low micro-hardness but of sufficiently high porosity in order to accommodate the Cr/Ni intake.

The synthesis of nanosized Ti-based nanogranules via plasma spraying is reported. The synthesis route involved use of both nitrogen and oxygen gases with varying results. In the case of nitrogen, a mixture of titanium nitrides were produced, yielding both the Ti2N and the sub-stoichiometric TiN0.61 compounds. In the case of oxygen, both the stoichiometric rutile and TiO ceramic phases were indexed. Based on EDS analysis, even fractional oxygen concentrations caused tungsten impurities which originated from the cathode electrode. The method yielded particle mass median sizes of the order of 15nm and the smallest particles detected were 5nm.

Close coupled gas atomization has been studied. Pitot tube gas flow measurements support a postulate of transition from an initial sonic to a supersonic and a final sonic state along the convergence region of the jets. Predictions of the d50 median diameter utilizing a two phase model for primary and secondary break up correlate strongly with experimental results from He-atomized Al alloys by a factor of 0.8216.