Wettability of reaction-bonded SiC surfaces in different concentrations of sulfuric acid: Experimental and simulation study

Abstract

Silicon carbide (SiC) exhibited high corrosion resistance and was able to maintain a stable solid-liquid interface, which has led to its widespread use in chemical equipment to achieve process intensification and efficiency enhancement. The performance of the equipment is directly influenced by the wettability of the solid-liquid interface. This underscores the necessity of investigating the wettability of SiC materials. In this study, reaction-bonded SiC surfaces with varying topography were fabricated through the adjustment of SiC powder particle size (D₅₀ 38.10 μm–2.34 μm) and the application of a reaction sintering process. Systematic examinations were conducted on the wettability of the reaction-bonded SiC surfaces in sulfuric acid solutions at concentrations of 0 wt%, 20 wt%, 50 wt%, and 80 wt% H₂SO₄. Results demonstrated that the surface morphology of reaction-bonded SiC was altered with decreasing median particle size, leading to a reduction in surface roughness from 9.043 μm to 0.653 μm. This morphological evolution was observed to induce a hydrophobic-to-hydrophilic transition, with maximum 124.371°and minimum 52.505° contact angles being measured in high- and low-surface-tension H₂SO₄ solutions, respectively. Furthermore, contact angles were observed to increase with the surface tension of H₂SO₄ solutions on the same surface. At the maximum 50 wt% and minimum 80 wt% surface tension concentrations, the contact angle decreased from 124.371° to 110.557°, which corresponded to an 11.1 % reduction. The conclusions were verified through theoretical calculations and simulations utilizing COMSOL Multiphysics software. This study offers a theoretical foundation for modulating the wettability of reaction-bonded SiC materials suited for use in corrosive liquid-phase environments through surface topography tailoring.