Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《中国腐蚀与防护学报》
Abstract: 316L stainless steel is widely used for enhancing the pitting resistance of pipelines in gas field. The corrosion environment is complex and diversified in different working districts of gas field. Therefore, it is necessary to develop a model for predicting the pitting resistance of pipelines serving in different corrosive environments. Critical pitting temperature (CPT) is considered as a criterion for evaluating the pitting resistance of stainless steel. Based on a survey on the operation situations of gas field, the relevant data of CPT for 316L stainless steel is acquired by potentiodynamic polarization method in solutions with various Cl- concentrations and pH values, which are selected to correspond with the real environments in operation. Then, an artificial neutral network (ANN) model is developed to predict the CPT, and therewith to compare with the measured data. The results show that the CPT decreases with the increase of Cl- concentration, but on which pH value has little influence. The developed ANN model has good ability to predict the CPT of 316L stainless steel, and can be used for the prediction of CPT in complex environments in gas field. It is also revealed that there is no interactive effect between Cl- concentration and pH value, and Cl- concentration was the main influencing factor on the CPT. Therefore, Cl- concentration will be peculiarly concerned with for the implementation of a corrosion control project in gas field.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-31 Cooperative journals: 《腐蚀科学与防护技术》
Abstract: Epoxy coatings with different additives of phytic acid were applied on rust and sand-blated Q235 carbon steels respectively. The adhesive strength and corrosion perfromance of these coatings were studied by means of adhesion measurement and electrochemical impedance spectroscopy (EIS). The results showed that the adhesive strength, corrosion resistance and the barrier effectiveness of the epoxy based coatings could be enhanced by the addition of phytic acid in the epoxy varnish. Moreover, phytic acid could inhibit the corrosion of the metal beneath the coating. The coating containing 3% phytic acid had the best corrosion perfromance.
Subjects: Materials Science >> Materials Science (General) submitted time 2023-03-18 Cooperative journals: 《材料研究学报》
Abstract: The waterborne epoxy coatings with polyaniline/vermiculite (PANI/VMT) as pigment were prepared. For the sake of identifying the functional groups of PANI/VMT, FT-IR measurement was performed. The thermal behavior of the pigments was characterized by thermal gravimetric analysis (TGA). The anticorrosion performance of waterborne epoxy coatings with different mass ratio of PANI/VMT was evaluated by electrochemical impedance spectroscopy (EIS) and salt spray test. The results show that a proper combination of the anodic protection ability of polyaniline and barrier property of vermiculite results in better performance of the PANI/VMT modified waterborne epoxy coating, for example, a coating with addition of 0.5% of PANI/VMT could provide a long- lasting anticorrosion protection for steel substrate.