ABSTRACT

The effects of silty sand and pH on the corrosion characteristics of 1Cr steel were investigated. The results revealed that silty sand changed the nucleation behaviour of FeCO₃ crystal from homogeneous nucleation to heterogeneous nucleation through increasing the critical supersaturation of FeCO₃. The compactness and protection of corrosion film were improved by silty sand. The amorphous FeCO₃ content decreased as the pH increased in the CO₂ environment with silty sand, while the Cr(OH)₃ content increased. The critical pH for the good corrosion resistance of 1Cr steel was 4.5. The amorphous FeCO₃ dominated the protective properties of corrosion film when the pH was lower than the critical pH, whereas the Cr(OH)₃ was predominant when the pH was higher than the critical pH. Therefore, the corrosion resistance of 1Cr steel was reduced and then enhanced with increasing pH under silty sand condition.

摘要

研究了粉砂和pH对1Cr钢腐蚀特性的影响。结果表明，粉砂通过提高FeCO 3 的临界过饱和度，使FeCO 3 晶体的形核行为由_均相形核转变为异相形_核。粉砂改善了腐蚀膜的致密性和保护性。在粉砂CO ₂环境中，随着pH值的增加，无定形FeCO _{3含量降低，而Cr(OH) 3}含量增加。1Cr 钢良好耐腐蚀性的临界 pH 值为 4.5。无定形 FeCO ₃当 pH 值低于临界 pH 值时，腐蚀膜的保护性能占主导地位，而当 pH 值高于临界 pH 值时，Cr(OH) ₃占主导地位。因此，在粉砂条件下，1Cr钢的耐腐蚀性能随着pH值的增加而降低后增强。