Influence of nitric acid on atmospheric corrosion of copper, zinc and carbon steels

AbstractIn this study, the effects of subppm levels of nitric acid (HNO3) on corrosion of copper, zinc and carbon steels are studied and compared with other reported data on corrosion of the same materials exposed to sulphur dioxide (SO2), nitrogen dioxide (NO2) and ozone (O3). The deposition velocity V d of HNO3 on the specimens, the corrosion rates and corrosion products of metals are determined by gravimetry, ion chromatography, X-ray diffraction and Fourier transform infrared (FTIR) microspectroscopy. The effect of HNO3 contaminated air on the corrosion rate of metals is far above that of SO2, NO2 or O3. This is mainly attributed to the relatively high sticking coefficient, water solubility and reactivity of HNO3. Despite the fact that ambient SO2 levels are still much higher than HNO3 levels, the results show that HNO3 plays a significant role for corrosion of copper and zinc, but not for carbon steel.