Corrosion behavior of porous Ti3SiC2 in nitric acid and aqua regia

Porous Ti3SiC2 with high purity was synthesized using TiH2, Si and C powders with mole ratio of Ti to Si to C being 3:1.2:2 by reactive synthesis method. The corrosion behaviors of porous Ti3SiC2 in nitric acid and aqua regia were investigated by immersing test. Scanning electron microscope (SEM), X-ray diffractometer (XRD), energy dispersive spectrometer (EDS) and X-ray photoelectron spectroscopy (XPS) were used to analyze the morphology, compositions and element contents of the samples before and after corrosion to determine the corrosion product and corrosion mechanism. The mass loss values of porous Ti3SiC2 are 26.9 and 132.5 μg/cm2, respectively after immersing in nitric acid and aqua regia for 600 h. The results indicate that Ti3SiC2 transforms to Ti5Si3 which has better corrosion resistance in nitric acid and aqua regia with mass loss values of 9.34 and 7.06 μg/cm2 under the same immersing time, respectively. The dramatic dissolution of porous Ti3SiC2 in the acids is due to its special microstructure.