جستجوی مقالات مرتبط با کلیدواژه "protective performance" در نشریات گروه "مواد و متالورژی"

Investigation of rheological parameters on the protective performance of an epoxy coating through wet and dry cycles has been studied using creep-recovery modeling. For this purpose, an epoxy resin was cured with four types of hardeners (Polyamine-based, Polyamidoamine-based, Polyether polyamine-based, and Cycloaliphatic Polyamine-based hardener) to achieve various adhesion behaviors and viscoelastic properties. The storage modulus, viscoelastic creep-recovery, permeability, electrochemical parameters, and glass transition temperature were determined. Samples were exposed to humidity chamber and adhesion was measured at wet and dry conditions over time. After drying, adhesion loss and recovery were evaluated by the pull-off test. The electrochemical behavior of coatings was studied by electrochemical impedance spectroscopy (EIS). It was found that the higher the elastic module, the more the adhesion loss. Recovery of adhesion after wet and dry cycles correlated with the reversible element of creep and recovery data. After that, creep recovery data were modeled and for the first time, two rheological parameters (viscose ratio and the elastic ratio of the viscoelastic behavior) were defined for predicting adhesion durability. A coating with a higher viscose property in creep recovery behavior shows week adhesion recovery . It may referred to irreversible strain in a coating that cannot be recovered after the elimination of stress. Additionally, it was found that a sample with excellent initial protective properties, higher elastic modulus, and low initial water permeability may quickly fail because of the adhesion failure after wet cycles.

This paper intends to evaluate the effect of curing time on the protective function of ecofriendly silane sol-gel coating applied on mild steel. The sol-gel coatings composed of three precursors, namely TEOS, MTES and GPS, were cured at 150 °C for 15, 45 and 75 min. In order to study the corrosion of coated steels, several surface analysis and electrochemical techniques were used. The optimum curing time was determined using the results of electrochemical impedance spectroscopy and polarization measurements. Moreover, HRSEM and water contact angle data indicated the optimum crosslink density of coating cured during 45 min revealing the most effective barrier effect.