Institutional Repository of Key Laboratory of Marine Environmental Corrosion and Bio-fouling, IOCAS
|Alternative Title||Preparation and properties of waterborne rust conversion coatings based on phosphoric acid and gallic acid|
|Place of Conferral||中国科学院海洋研究所|
|Keyword||锈转化涂料 转锈剂 没食子酸 丙烯酸乳液 防腐蚀 Rust conversion coating Rust converter Gallic acid Acrylic emulsion Anticorrosion|
There are anti-corrosion maintenance problems in the service of steel equipment. Water-based rust conversion coatings (RCC) conform to the trend of environmental protection and have broad application prospects. Exploring effective water-based RCC, and clarifying its principle of action and applicable conditions can provide important technical support for the anti-corrosion of in-service facilities and equipment.
This thesis takes the rusted steel (RS) prepared by the constant temperature and humidity (CTH) method as the research object, and explores the preparation of rust converter (RC) and RCC. The results show that the composition and structure of the obtained rusted steel are similar to the atmospheric corrosion of carbon steel. Therefore, it is an ideal object for the research of RCC. Adding gallic acid (GA) and phosphoric acid (PA) to the vinyl chloride-acrylic acid emulsion with a reasonable film-forming aid and defoamer can prepare effective water-based RCC.
The rust conversion performance and mechanism of phosphoric acid-gallic acid in vinyl chloride-acrylic emulsion were systematically studied. The results show that the RCC can effectively treat the RS prepared by CTH method, and can form a black conversion film with good adhesion and anti-corrosion properties. The conversion products are ferric phosphate and ferric gallate. The ferric gallate is evenly distributed in the film, and the ferric phosphate accumulates in the rust conversion film (RCF) and on the surface of unreacted rust. The unreacted rust between the substrate and the conversion film limits the further improvement of adhesion and corrosion resistance.
The application effect of the RCC on the rusty surface of different structures was further studied. The results show that the nonadherent rust (NAR) of the RS prepared by salt spray corrosion test (SSCT) and coastal outdoor exposure (COE) is uniform and complete. The difference is that the adherent rust (AR) layer prepared by SSCT is unevenly distributed, while the AR layer obtained by COE is evenly distributed. The RCC forms a non-uniform RCF with many micropores on the RS prepared by SSCT, and has poor corrosion resistance. This RCC can form a uniform RCF on the surface of the RS prepared by COE, and has good anti-corrosion performance when the coating is intact. However, there is still unreacted rust under the RCF, and corrosion will occur quickly once the coating is damaged. Therefore, the RCC can achieve the best rust conversion and anti-corrosion effect only by achieving more thorough rust conversion on the evenly AR layer.
In this paper, a waterborne RCC based on PA and GA was prepared, and the anti-corrosion effect, rust conversion mechanism and applicable conditions of this coating were deeply studied. The above research provides some theoretical and experimental basis for the more reasonable development of RCC based on gallic acid and its derivatives.
|Subject Area||海洋化学 ; 海洋科学其他学科|
|MOST Discipline Catalogue||理学::海洋科学|
|Funding Project||National Natural Science Foundation of China ; National Natural Science Foundation of China|
|王鑫. 磷酸-没食子酸基水性锈转化涂料的制备及性能研究[D]. 中国科学院海洋研究所. 中国科学院大学,2021.|
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