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In this study, nano-sized Si3N4 (0, 0.5, 1.0 and 1.5 vol%)/Al composites were fabricated using a powder metallurgy method involving microwave sintering technique followed by hot extrusion.

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Abstract:Ni-B/Y 2 O 3 composite coatings were developed through an electrodeposition process to study the effect of addition of Y 2 O 3 particles on structure, surface, thermal, mechanical, and anticorrosion properties of Ni-B coatings. It is revealed that parent crystal structure of Ni-B matrix is preserved by addition of Y 2 O 3 , however, a noticeable improvement in crystallinity is observed. The analysis of the surface exhibits formation of dense and nodular deposits in the two types of coatings, but incorporation of Y 2 O 3 particles in Ni-B matrix has resulted in a noteworthy change in grain size and surface roughness. Thermal analysis of the surfaces indicates that Ni-B-Y 2 O 3 composite coatings demonstrate superior thermal stability compared to Ni-B coatings. The nanoindentation analysis shows a significant enhancement in the mechanical characteristics of the Ni-B matrix by addition of Y 2 O 3 particles. This may be contemplated as the result of grain refinement and dispersion hardening of the Ni-B matrix by the presence of hard Y 2 O 3 particles. A decent improvement in the corrosion protection efficiency (73.6%) is also observed by addition of Y 2 O 3 particles into Ni-B matrix. Simultaneous improvement of mechanical and anticorrosion properties suggests potential applications of Ni-B-Y 2 O 3 coatings in oil and gas, automobile, and many other industries.