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Heterocoagulation in alumina–silica suspension is studied using 2-dimensional discrete element method simulations. Controlling the structure and stability of the binary suspensions via selecting the appropriate size of precursors is crucial in ceramics processing. Alumina and silica particles with a broad range of sizes and size ratios are investigated. The size and the size ratio determine the degree of heterocoagulation and impact the suspension’s structure. Analyzing simulation results shows that when the sizes of silica and alumina particles are comparable, and the radii of particles are below 300 nm, a chain-like structure is formed. In suspensions with high size asymmetry, smaller silica particles surround larger alumina particles, and the degree of heterocoagulation is dependent on the composition of the suspension. The results show that suspension composition can also be used to tune the heterocoagulation structure.

ABSTRACTIn this study, electroless nickel–phosphorus plating was optimised for WC–Co powder using different bath loads and then subjected to a high-velocity oxygen fuel process. The produced Ni–P-coated WC–12Co powders were subsequently used as HVOF feedstock materials. Based on the SEM results, an increase in the bath load resulted in a decrease in the thickness of the Ni–P coating formed on the WC–12Co powders. Moreover, applying the HVOF process led to a lower porosity and roughness and a higher thickness of nickel coating, whereas applying a suitable thickness of this coating can prevent the destructive W2C phase. Finally, a bath load of 16 g L–1was determined as the optimum value to achieve a proper thickness of the Ni–P, extremely low porosity (0.3%), good surface roughness (5 μm), and high microhardness (1112 Hv) in the produced coating.

In this study, electroless nickel–phosphorus plating was optimised for WC–Co powder using different bath loads and then subjected to a high-velocity oxygen fuel process. The produced Ni–P-coated WC–12Co powders were subsequently used as HVOF feedstock materials. Based on the SEM results, an increase in the bath load resulted in a decrease in the thickness of the Ni–P coating formed on the WC–12Co powders. Moreover, applying the HVOF process led to a lower porosity and roughness and a higher thickness of nickel coating, whereas applying a suitable thickness of this coating can prevent the destructive W2C phase. Finally, a bath load of 16 g L–1was determined as the optimum value to achieve a proper thickness of the Ni–P, extremely low porosity (0.3%), good surface roughness (5 µm), and high microhardness (1112 Hv) in the produced coating.