Effect of LBE Corrosion on Surface Wettability of Ti₃SiC₂ at 450°C

Abstract

Due to the excellent properties such as high temperature resistance, corrosion resistance, good heat conduction and plasticity, MAX-phase materials have been considered as one of the candidate materials for cladding and coating material in liquid metal cooled fast reactors. In this paper, the evolution of surface structure and wettability of Ti3SiC2 under short-term LBE corrosion were studied experimentally. The samples were immersed in LBE with saturated oxygen concentration for 100, 300 and 500 h at 450°C. The surface and cross section morphology as well as composition distribution of corrosion samples were analyzed by metallographic microscope, scanning electron microscope (SEM) and energy dispersive X-ray fluorescence spectrometer (EDX). Meanwhile, five-point fitting method was used to determine the contact angle of raw and corroded samples at 450°C. The results showed that the surface smoothness of Ti3SiC2 samples degenerated after LBE corrosion. No stratification was observed in all corroded samples but the transition layer was found in the surface region of corroded samples and its thickness increased with the increase of corrosion time. In the sample corroded for 500 h, the transition layer near the matrix side tended to transform into stable oxidation layer. In addition, the increase of corrosion time will lead to the reduction of LBE wetting on the surface of materials, which can effectively affect heat transfer of the surface.