Corrosion behaviors of Ti3SiC2/Cu in dilute HNO3 and concentrated H2SO4 and its corrosion mechanism

Abstract

The corrosion behaviors of Ti3SiC2/Cu composites in dilute HNO3 (11.6%) and concentrated H2SO4 were investigated by the soaking method. The morphology, composition and elemental content of the composites before and after corrosion were analyzed to determine the corrosion products and the corresponding corrosion mechanism. The results found that the mass losses of the Ti3SiC2/Cu composites after soaking in the dilute HNO3 and concentrated H2SO4 for 50 days were 148.58 mg/cm2 and -2.90 mg/cm2, respectively, which indicated that the corrosion resistance of Ti3SiC2/Cu composites in concentrated H2SO4 was superior than that in dilute HNO3. It was deduced that in dilute HNO3, Cu in the Ti3SiC2/Cu composites reacted with dilute HNO3 and dissolved in it, and Ti and Si in the Ti3SiC2/Cu composites reconstructed to form Ti5Si3. The better corrosion resistance of Ti3SiC2/Cu composites in concentrated H2SO4 was owing to a passivation film consisting of TiO2 and SiO2. Moreover, the appearance of the formation of CuO in the initial corrosion further strengthened its corrosion resistance in concentrated H2SO4.