Corrosion resistance for biomaterial applications of TiO2 films deposited on titanium and stainless steel by ion‐beam‐assisted sputtering

Electrochemical characteristics of titanium based biomaterials in artificial saliva

“…The impedance of CPE is defined as Z CPE ¼ 1=QðjvÞ where Q is the combination of properties related to both the surfaces and electroactive species independent of frequency; n is related to a slope of the log Z versus log Bode-plots; v is the angular frequency, and j is imaginary number (j 2 ¼ À1). Q is an adjustable parameter used in the fitting routine: when the value of n is equal to 1, the CPE acts as a pure capacitor [13]. The components of the EC are: R s , ohmic resistance of the electrolyte; R 1 , resistance of the outer porous layer; R 2 , resistance of the compact inner layer; CPE 1 , constant phase element of the outer porous layer; CPE 2 , constant phase element of the compact inner layer.…”

“…DC electrochemical methods are commonly used to evaluate corrosion, but over the past decade many articles on the electrochemical impedance spectroscopy (EIS) have been published [7][8][9][10][11][12][13][14][15][16][17]. Kovacs [18] has demonstrated that the AC impedance method is particularly useful when some electrochemical behavior changes as a function of time are recorded, because it is a non-destructive technique.…”

In vitro corrosion study by EIS of a nickel-free stainless steel for orthopaedic applications

“…Instead of pure capacitors, constant phase elements (CPE) were introduced in the fitting procedure to obtain good agreement between the simulated and experimental data. The impedance of CPE is defined as Z CPE ¼ 1=ðQðJoÞ n Þ; where Q ðo À1 s n cm À2 Þ is the combination of properties related to both the surface and the electroactive species independent on frequency; ''n'' is [14]. CPE is then given as both the parameter Q and the exponent ''n''; it should be stressed that for simplicity Q is often considered as a capacitance.…”

“…This type of circuit was first proposed by Pan et al [14] to simulate data for titanium in saline solutions, and can be regarded as an electrical representation of a twolayer model of the oxide film, consisting of a barrier compact inner film and a porous outer layer. A twolayer structure has also been hypothesized for the passive film on stainless steels [24].…”

“…Direct current (DC) electrochemical methods are commonly used to evaluate corrosion, but over the past decade many articles on the electrode impedance spectroscopy (EIS) have been published [8][9][10][11][12][13][14][15][16]. Kovacs demonstrated [17] that the alternating current (AC) impedance method is particularly useful when monitoring some electrochemical changes as a function of time, being a non-destructive technique.…”