SO2-4 ,PO3 4- 对曼尼希碱酸化缓蚀剂缓蚀性能的影响

目的：研究废酸液中介质离子对曼尼希碱酸化缓蚀剂缓蚀性能的影响,以解决碳钢在酸液中的腐蚀问题。方法采用静态失重法、极化曲线、扫描电镜及能谱分析法,研究SO2-4,PO3-4对曼尼希碱型酸化缓蚀剂缓蚀性能的影响,并探究其作用机理。结果在10%(质量分数)盐酸、0.1%(质量分数)曼尼希碱的缓蚀介质中,随SO2-4质量分数的增大,腐蚀电流密度由2.81μA/cm2增加至7.32μA/cm2,腐蚀速率显著增大,缓蚀效果变弱；随PO3-4质量分数的增加,腐蚀电流密度由2.81μA/cm2减小至2.41μA/cm2,腐蚀速率减小,缓蚀效果变强。结论 SO2-4会通过钢铁表面已经形成的吸附膜上的细孔和缺陷渗入膜内,使膜发生开裂,从而侵蚀和破坏已经形成的吸附膜,抑制缓蚀剂的缓蚀效果；PO3-4与腐蚀产物Fe3+络合并在钢材表面形成一层致密的保护层,使缓蚀剂形成的吸附膜更加致密,阻止腐蚀性介质与金属表面接触,同时增加对离子或溶解氧的扩散阻力,提高缓蚀剂的缓蚀效果。

Influence of SO2-4 and PO3 4- on the Inhibition Performance of Compounded Mannich Base Hydrochloric Acid Corrosion Inhibitor

Objective To explore the effects of SO2-4 and PO3-4 on the performance of mannich base hydrochloric acid corrosion inhibitor. Methods Using static weight-loss method, polarization curve, scanning electron microscope and energy spectrum analy-sis, the effects of SO2-4 and PO3-4 on the performance of mannich base hydrochloric acid corrosion inhibitor were studied and its mechanism was explored. Results In corrosion medium with 10%HCl and 0. 1% mannich base, with the increase of SO2-4 mass fraction, the corrosion current density increased from 2. 81μA/cm2 to 7. 32μA/cm2 , the corrosion rate significantly increased and the corrosion inhibition effect was weakened;on the contrary, with the increase of PO3-4 mass fraction, the corrosion current density decreased from 2. 81 μA/cm2 to 2. 41 μA/cm2 , the corrosion rate decreased and the corrosion inhibition effect was strengthened. Conclusion SO2-4 penetrated into the steel surface adsorption film through the holes and defects, forming cracks in the film, leading to erosion and damage of the adsorption film, and the effect of mannich acid hydrochloric acid corrosion inhibitor was suppressed. The corrosion products of PO3-4 and Fe3+ formed a layer of dense membrane on the steel surface, making the adsorption film formed by the corrosion inhibitor more dense, leading to difficulty in the contact of corrosive medium and metal surface, meanwhile, the diffusion resistance of ions or dissolved oxygen was increased, and the performance of mannich base hydrochloric acid corrosion in-hibitor was promoted.