Characterization of Ni coating layer of Al2O3 particles and their wettability behavior in Al2O3@Ni/Al-10Si composites

The influence of a Ni coating on Al2O3 particles on the wettability behavior of Al2O3/Al-10Si composites was investigated using the sessile drop method. The results showed that a uniform NiAl2O4 layer was coated on surfaces of Al2O3 particles by electroless plating, which adsorbed significant amounts of Ni. The contact angles of Al2O3@Ni/Al-10Si composites at 1273 K and 1373 K decreased to 83.5 degrees and 82.3 degrees, respectively, mainly because of the rough NiAl2O4 layer on the surface of Al2O3, the heat released by the interfacial reaction, and the formation of an Al-Ni phase. The Orowan strengthening caused by the uniformly-dispersed Al2O3@Ni particles lead to the compressive stress of the composites increased to 514 MPa.