On the Distribution of Ni_3S_2 in Corrosion Layers of NiO-Ni_3S_2

摘要

Qualitative studies have been made of the interfacial tension between Ni_(3±x)S_2 and different oxides (NiO, CoO, and feldspar). The results suggest reasons why Ni_(3±x)S_2 is distributed as an interconnected network along NiO grains in rapidly growing scales formed during reaction of nickel with SO_2 and SO_2+ O_2 at temperatures from about 550 to 850℃. In the system NiO-Ni_(3±x)S_2 inter-facial energies may stabilize a network of sulfide along edges of NiO grains. Ni_(3±x)S_2 does not wet the silicate material (feldspar), and this is consistent with previous interpretations that silicates formed by segregation of silicon to NiO interfaces disrupt the sulfide network in scales and thereby provide improved corrosion resistance.