Atomistic insight into the wetting behavior of Fe nanoparticles on dicalcium silicate interfaces: morphology and temperature dependence

Abstract

Clarifying the wetting characteristics between dicalcium silicate (2CaO·SiO₂, C₂S) formed by lime melting in the steelmaking process and molten steel is key to reducing lime consumption and waste residue discharge. The present work uses molecular dynamics simulation to study the melting and wetting behavior of four morphologies (cube, sphere, tetrahedron, cylinder) of Fe nanoparticles on C₂S substrates within the temperature range of 1573–2073 K. The results indicate that increasing temperature enhances the total potential energy of the simulated system and reduces stability. The increase in temperature has almost no effect on the short-range properties of FeFe atom pairs in Fe nanoparticles, but promotes the shortening of FeFe atom pairs at longer distances (4.0–7.0 Å). Fe nanoparticles with high temperature, small size system, and high initial potential energy exhibit better wettability on C₂S substrates. The difference in the self-diffusion coefficient of Fe atoms in different morphologies of Fe nanoparticles within the range of 1573–2073 K is determined by the differences in system size and energy stability of Fe nanoparticles. The morphology effect significantly affects the wetting performance, with tetrahedron Fe nanoparticles having the best wetting performance and cube Fe nanoparticles having the worst. The increase in temperature accelerates the hydrophobic-hydrophilic transition, and systems above 1673 K can achieve hydrophilic wetting within 50 ps, with contact angle and time following an exponential decay law. The current research provides atomic-scale theoretical insights into the interfacial behavior of iron liquid/slag in metallurgical processes.