有机膦酸锈转化剂的腐蚀保护机制研究

Study on Corrosion Protection Mechanism of Organic Phosphonic Acid Rust Converter

制备了一种以羟基乙叉二膦酸(HEDP)作为锈转化剂的转化型带锈涂料,通过对添加不同质量分数的HEDP的涂料样板的盐雾试验、电化学测试及分析,研究了HEDP作为锈转化剂的带锈涂料的耐腐蚀性能。综合评定HEDP质量分数为5%时,防腐蚀效果最好。利用能谱(EDS)分析和红外光谱(FT-IR)技术,对HEDP的防锈机理和与铁锈的反应情况进行了研究。EDS线扫描结果表明:当HEDP加入到水性涂料中时,磷元素集中在锈层和涂层的交界处;红外测试结果表明:HEDP主要与铁锈中疏松的纤铁矿反应生成螯合物,形成稳定的络合物保护膜,对基底进行保护。

A rust-converting coating was prepared using 1- Hydroxyethylidene- 1,1- diphosphonic acid （HEDP） as rust converter. The influence of HEDP on the anticorrosive per- formance of coatings was studied via salt spray tests, electrochemical impedance spectroscopy （EIS） tests and analysis. When the mass fraction of HEDP in the coating was 5%, the best anticorrosive effect was obtained. The reaction of HEDP with rust was studied through EDS and FT-IR. The results of EDS showed that the phosphorus was concentrated in the boundary between the rust and the coating when HEDP was added into the coating. The FT-IR showed that HEDP was mainly reacted with the loosened lepidocrocite of rust to produce a chelated com- pound, which further formed a stable protective layer on the steel substrate.