10#碳钢在NaHCO3-Na2SO4体系中的腐蚀规律研究

研究了在NaHCO3-Na2SO4体系中，温度、pH值、侵蚀性离子(Cl-，S2-，HCO3，NO3-，CO32-)以及缓蚀性离子(MoO42-，NO2-，Cr2O72-，Zn2+)对10号碳钢年腐蚀速率的影响。研究结果表明，在60℃和80℃条件下，HCO3-离子均存在着一个临界浓度（约0.1mol/L），当HCO3-离子浓度等于0.1mol/L时，腐蚀速率很小，几乎为零；当HCO3-离子浓度低于或高于此浓度时腐蚀速率都有所增大，但当浓度达到0.2mol/L时腐蚀速率有下降趋势,说明高浓度的HCO3-离子对碳钢具有一定的保护性。侵蚀性离子对碳钢腐蚀作用由小到大的顺序为Cl-＜NO3-＜S2-＜CO32-。 MoO42- ，NO2- ，Zn2+等缓蚀性离子，可以通过提高溶液的pH值，在碳钢表面生成保护膜等对碳钢起到保护作用；而Cr2O72-却能降低溶液的pH值，促进碳钢的腐蚀。

RESEARCH OF THE CORROSION LAW OF 10# CARBON STEEL IN NaHCO3-Na2SO4 SYSTEM

Factors influenced the corrosion rate of 10# carbon steel in the system of NaHCO3-Na2SO4 solution, such as temperature, pH value, corrosive ions (Cl-, S2-, HCO3-, NO3-, CO32-) and rust inhibitive ions (MoO42-, NO2-, Cr2O72- , Zn2+), were investigated. Results showed that at 60℃ and 80℃ with a critical HCO3- concentration of 0.1 mol/L, the corrosion rate of 10# carbon steel was almost zero; when HCO3- concentration was higher or lower than 0.1 mol/L, the corrosion rate increased; when HCO3- concentration reached 0.2 mol/L, the corrosion rate seemed to have a decrease trend, which indicated that high concentration of HCO3- ions could suppress the corrosion of carbon steel by forming a passivation film. The erosion of corrosive ions to carbon steel increased from low to high in the order of Cl-＜NO3-＜S2-＜CO32-. Rust inhibitive ions, MoO42-, NO2- and Zn2+ ions, could protect the steel from corrosion by raising the solution pH value to form a protective film on the surface of carbon steel; yet Cr2O72- ions would decrease the pH value of the solution, and thus the corrosion was enhanced.