Effect of alloy composition on wetting behavior of Sn–Co–La alloy on NdFeB substrate

The alloy composition influences the wettability of molten metal at high temperatures. A new Sn–Co–La alloy was used as a surface adhesive for NdFeB material and the wettability and contact surface morphology of the alloy on NdFeB substrate were studied. To explain the connectionism of alloy on NdFeB substrate following lanthanum addition, the interfacial reaction activation energy of the Sn–Co–La/NdFeB system was calculated. The results show that when the percent of cobalt in the alloy is grown, its melting point rises, making it harder to wet on the NdFeB surface. The activation energy of the interfacial contact between the alloy and the NdFeB substrate surface is reduced from 168.371 kJ/mol to 107.062 kJ/mol when the Lanthanum concentration is increased from 0.5 wt% to 1 wt%. The inclusion of lanthanum increases the thickness of intermetallic compounds and improves the wettability of the alloy and substrate.