Characterization of Phosphate Coatings: Influence of the Acid Pickling Conditions

Materials

Carmen Pérez¹  Sheila Silva-Fernández¹  X.Ramón Nóvoa¹  Belén Díaz¹ 

[1] CINTECX, Universidade de Vigo, ENCOMAT group, Campus universitario As Lagoas, Marcosende, 36310 Vigo, Spain;

关键词: phosphate;    acid pickling;    citric acid;    corrosion;    impedance;    porosity;   

DOI  :  10.3390/ma14041048

来源: DOAJ

【 摘 要 】

This research emphasizes the importance of the acid cleaning prior to the phosphate development on high-strength steel rods. It compares the phosphate properties achieved after different acid-pickling conditions. The most common inorganic acids were considered in this study. Additionally, taking into account the environmental and safety concerns of these acids, the assessment of a less harmful organic acid is presented. This study revealed significant differences in the coating morphology and chemical composition whereas no great changes were found in terms of the coating weight or porosity. Thus, hydrochloric and sulfuric acid promote the growth of a Fe-enriched phosphate layer with a less conductive character that is not developed after the pickling with phosphoric acid. The phosphate developed after the citric acid pickling is comparable to that developed after the inorganic acids although with a porosity slightly higher. The temperature of the citric acid bath is an important parameter that affects to the phosphate appearance, composition, and porosity.

【 授权许可】

Unknown