STUDIES OF WATER TRANSPORT BEHAVIOR AND IMPEDANCE MODELS OF EPOXY-COATED METALS IN NACL SOLUTIONBY EIS
1. The rapid increase of the coating capacitance in the initial period of immersion suggests that the water may permeate into the coatings through the micro-pores formed by solventvolatilization during the curing process(1H2O).
2. Water diffusion coefficient (D) in an organic coating can be obtained from the time dependence of coating capacitance in the case of Fickian diffusionby using the following equation:
where Ct is the coating capacitance at time t, C0 the coating capacitance at time t = 0, i.e. the dry coating capacitance, C∞ the coating capacitance atsaturation, and L the coating thickness.
LA DEDUCCION DE ESA ECUACION ESTA EN “Determination of water uptake and diffusion of Cl− ion in epoxy primer on aluminum alloys in NaCl solution byelectrochemical impedance spectroscopy”
3. Usually the coating prepared is partially heterogeneous or has a lot of micro-pores.With the increase of coating thickness, the following painting may block thepores formed in the pervious operation, resulting in the formation of more compact products and the enhancement of coating homogeneity. (1H2O).
4. The water diffusion coefficients range of 10−8to 10−12 cm2/s for the coatings with good barrier performance at room temperatura reported in literatures(1H2O).
5. In the case of Fickian diffusion, the time for water uptake achieving thesaturation amount in coatings, ts, can be determined using the following equation
MONITORING THE DEGRADATION OF A HIGH SOLIDS EPOXY
COATING BY MEANS OF EIS AND EN
1. Lo siguientedescribe el proceso de degradacion en una pintura epoxica de altos solidos: In accordance with these figures, two main processes can occur in parallel: the chemical degradation and the loss of...