Copper plating on water-soluble NaCl particles by evaporative crystallization and its effect on the pore structure of infiltrated AlSi12 alloy foam

A new evaporative crystallization method was used to plate copper on water-soluble NaCl particles. Cu(NO 3 ) 2 ·3H 2 O was crystallized on NaCl particles by the heated ethanol volatilization, and then thermally decomposed to obtain CuO coating which was finally reduced to Cu coating. The affecting factors of coating effect and the influence of copper-plated NaCl particles on the pores structure of infiltrated AlSi12 foam were studied. The thermal oxidation pretreatment of NaCl particles increased the number of oxygen-containing functional groups and the uniform distribution of thermal etch pits, which improved the bonding strength between NaCl particles and Cu(NO 3 ) 2 ·3H 2 O coating. The addition of Tween-60 and PEG-6000 inhibited the micro-dissolution of NaCl particles in ethanol and promoted the formation of complete CuO coating. Infiltrated AlSi12 foam prepared from copper-plated NaCl particles had a more homogeneous pore structure and smaller pore size deviations than infiltrated AlSi12 foam obtained with uncoated NaCl particles, indicating that copper plating significantly improved the wettability of NaCl particles and AlSi12 alloy melt. This paper presents a new and low-cost surface treatment method, which provides a useful reference for the surface modification and application of water-soluble particles.