Potentiodynamic polarisation tests

Matthews, 2000). A phosphate salt solution and an aqueous suspension of HAp powder were used as an electrolyte for PEO and EPD, respectively. The corrosion resistance was assessed by potentiodynamic polarisation tests in a buffered physiological solution (see also Kwok et al., 2009). The results of this study indicated that a hybrid combination of PEO and EPD produces an osseoconductive phase-pure ITAp layer and an anticorrosive titania interlayer that promise to provide good mechanical and biochemical stability in the highly corrosive environment of the human body. Other studies involving titania bond coats include Albayrak and Altintas, 2010 Paluszkiewicz, Dlugon andKwiatek, 2012 Rath etal., 2012 and Jain etal. (2013). 

Figure 7.56 Determination of the anodic (pa) and cathodic (Pc) Tafel slopes from the potential versus current density plot obtained by potentiodynamic polarisation testing.

Steel Cyclic voltammetry Tafel polarisation in 0.1 MHCl EIS in 0.5 M NaCl, 0.1 MHCl Potentiodynamic polarisation in 0.5 M H SO All corrosion tests show the best performance of PPy single coating with respect to the single PANl coating, and PANI/PPy and PPy/PANl bi-layer coatings. [29]... 

DC polarisation tests took place in a three-electrode electrochemical cell where the area of the working electrode (modified Al-2024 T3) exposed to the corrosive solution was 1 cm. For these measurements, a platinum foil and a SCE were used as the counter and the reference electrodes, respectively. Potentiodynamic tests were carried out by scanning the potential between -1 V and 0 V vs SCE at a rate of 1 mV s. The resulting graphics were fitted to the Tafel plots allowing the corrosion current and potential, and the polarisation resistance to be extrapolated. Corrware software was used for fitting. 

A detailed and well-referenced account of electrochemical methods of testing has been written by Dean, France and Ketcham in a section of the book by Ailor. ASTM G5 1987 outlines standard methods for making potentiostatic and potentiodynamic anodic polarisation measurements and ASTM G3 1974 (R1981) gives conventions applicable to electrochemical measurements in corrosion testing. 

Standard reference test method for making potentiostatic and potentiodynamic anodic polarisation measurements Recommended practice for atmospheric environmental exposure testing of nonmetal-lic materials... 

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