目的：提高0.5 mol/L HCl中植酸对热轧碳钢( HRCS)的缓蚀性能。方法用失重法和电化学阻抗法测试植酸、吐温-40以及复配缓蚀剂的缓蚀效率,从热力学和动力学方面分析复配缓蚀剂的作用机制。结果失重法测试表明,植酸和吐温均对热轧碳钢有一定缓蚀作用。当293 K,植酸质量浓度为0.3 g/L时,缓蚀效率达到69.1%,在质量浓度为0.8 g/L时缓蚀效率下降为9.6%；吐温-40的缓蚀效率随着质量浓度的增大而增大,0.8 g/L时达到73.4%。在0.5 mol/L盐酸中加入0.05 g/L吐温-40后,复配缓蚀剂的缓蚀效率随着质量浓度的增加而增大,且优于植酸和吐温-40单独使用,表现出协同效应。电化学测试得到了相同的结论,表明复配缓蚀剂在碳钢表面产生自发的Langmuir吸附,使碳钢腐蚀反应的活化能增大,是熵减少的放热过程。结论吐温-40和植酸在盐酸中对热轧碳钢的腐蚀有缓蚀协同作用。
Objective To improve the corrosion inhibition performance of phytic acid for hot rolled carbon steel (HRCS) in 0. 5 mol/L HCl soltuion. Methods The corrosion inhibition efficiency of phytic acid, Tween-40, and their compound on carbon steel was measured by weight-loss method and electrochemical impedance spectrometry tests. The inhibition mechanism of the compound inhibitor was analyzed using thermodynamics and kinetics. Results It was revealed by weight-loss measurement that either phytic acid or tween-40 alone had limited inhibitory effect on the corrosion of HRCS in hydrochloric acid. The inhibition efficiency of phy-tic acid reached the max value of 69. 1% when the concentration was 0. 3 g/L at 293 K, then decreased with further addition of in-hibitor and was reduced to 9. 6% when the concentration of phytic acid was 0. 8 g/L. On the other hand, the inhibition efficiency increased with the increase of the tween-40's concentration, which reached the value of 73. 4% at 0. 8 g/L, 293 K. When Tween-40 (0. 05 g/L) was added into the solution, the inhibition efficiency of the compound inhibitor increased even if the concentration of phytic acid exceeded 0. 3 g/L. The corrosion inhibition efficiency of compound inhibitor was higher than the sum of phytic acid's and Tween-40's efficiency, which suggested synergistic effect. The same result could be concluded from electrochemical impe-dance spectrometry measurement. Further analysis revealed that the adsorption of the compound inhibitor on the surface of carbon steel obeyed Langmuir adsorption isotherm equation, which improved the activation energy( Ea ) of the corrosion procession, leading to the decrease of entropy. Conclusion Tween-40 and phytic acid showed synergistic corrosion inhibition effect on the HRCS in hy-drochloric acid.
参考文献
- 下载量()
- 访问量()
- 您的评分：
-
10%
-
20%
-
30%
-
40%
-
50%