TY - CHAP
T1 - A new approach to describe the passivity of nickel and titanium oxides
AU - Cabrera-Sierra, Román A.
AU - González, Ignacio
AU - Ávalos-Martínez, Jorge
AU - Vázquez, Gerardo
AU - Pech-Canul, Máximo A.A.
N1 - Funding Information:
The authors are grateful for the financial support of CONACyT project 47162.
PY - 2006
Y1 - 2006
N2 - This chapter presents a new model to describe the passivity of nickel and titanium oxides. This model is based on the defect model (PDM) but it incorporates reactions at the interfaces, which consider that diffusion of hydroxide ions (OH-) may take place through a mechanism similar to that proposed for pitting. The impedance model, derived within the framework of the PDM allowed the simulations of impedance diagrams typical for passive films having n-type and p-type semiconductor behavior. Contribution of hydroxyl ion vacancies to the impedance response was shown to consist of a diffusional impedance with a time constant higher than that for cation vacancies (p-type electronic character) and higher than that for anion vacancies (n-type electronic character). The very good agreement between experimental and calculated impedance diagrams, and the reasonable values of parameters used in the simulations support the validity of this model.
AB - This chapter presents a new model to describe the passivity of nickel and titanium oxides. This model is based on the defect model (PDM) but it incorporates reactions at the interfaces, which consider that diffusion of hydroxide ions (OH-) may take place through a mechanism similar to that proposed for pitting. The impedance model, derived within the framework of the PDM allowed the simulations of impedance diagrams typical for passive films having n-type and p-type semiconductor behavior. Contribution of hydroxyl ion vacancies to the impedance response was shown to consist of a diffusional impedance with a time constant higher than that for cation vacancies (p-type electronic character) and higher than that for anion vacancies (n-type electronic character). The very good agreement between experimental and calculated impedance diagrams, and the reasonable values of parameters used in the simulations support the validity of this model.
UR - http://www.scopus.com/inward/record.url?scp=84882858189&partnerID=8YFLogxK
U2 - 10.1016/B978-044452224-5/50052-4
DO - 10.1016/B978-044452224-5/50052-4
M3 - Capítulo
SN - 9780444522245
SP - 325
EP - 330
BT - Passivation of Metals and Semiconductors, and Properties of Thin Oxide Layers
PB - Elsevier
ER -