The effect of annealing on the tribological and corrosion properties of Al-12Si samples produced by selective laser melting (SLM) is evaluated via sliding and fretting wear tests and weight loss experiments and compared to the corresponding material processed by conventional casting. Sliding wear shows that the as-prepared SLM material has the least wear rate compared to the cast and heat-treated SLM samples with abrasive wear as the major wear mechanism along with oxidation. Similar trend has also been observed for the fretting wear experiments, where the as-prepared SLM sample displays the minimum wear loss. On the other hand, the acidic corrosion behavior of the as-prepared SLM material as well as of the cast samples is similar and the corrosion rate is accelerated by increasing the heat treatment temperature. This behavior is due to the microstructural changes induced by the heat treatment, where the continuous network of Si characterizing the as-prepared SLM sample transforms to isolated Si particles in the heat-treated SLM specimens. This shows that both the wear and corrosion behaviors are strongly associated with the change in microstructure of the SLM samples due to the heat-treatment process, where the size of the hard Si particles increases, and their density decreases with increasing annealing temperature.

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In the present study nano-tungsten carbide particles were generated in a wire explosion process. The plasma generated during the wire explosion process was analyzed using optical emission spectroscopy (OES). The impact of ambient pressure on the plasma temperature, electron density and plasma lifetime was studied. Lifetime variations of the plasma produced under different experimental conditions were analyzed. The produced nanoparticles were characterized through wide angle X-ray diffraction (WAXD) and transmission electron microscopy (TEM) studies. Particles produced with a negative DC charging voltage had a larger mean size when compared to a positive charging voltage. Polarity dependence on the plasma duration was observed where plasma was sustained for a longer duration with a negative DC charging voltage.