Incorporation and Migration of Phosphorus Species in Anodic Alumina Films Containing Tungsten Tracer Layers

Abstract

Al–W nanolayers have been used previously to investigate the mechanism of formation of porous anodic films on aluminum in phosphoric acid. The present study considers the interactions of the tungsten tracer species and phosphorus species in the films and the consequence to the transport of the tracer. The findings showed that phosphorus species migrate inward and pass through the nanolayer of outwardly migrating tungsten species. Further, the migration behaviors indicated negligible influence of either species on the migration of the other.

Photoelectrochemical evidence of nitrogen incorporation during anodizing sputtering – deposited Al–Ta alloys

“…the distance travelled by the photocarriers before their effective separation by the electric field. In eqn (7) the only parameter that changes with irradiating photon wavelength is r 0 , which is a function of the excess energy DE = (hn À E trans ), i.e. the extra energy with respect to that necessary for the optical transition.…”

“…However, the film structure and the composition are also dependent upon the electrolyte due to the possible incorporation of foreign species from the anodizing bath. [6][7][8] This is very important if we consider that the presence of foreign species in anodic films could affect the electronic properties of the films with possible detrimental effects on the dielectric properties of the oxides.…”

High-resolution neutron imaging: a new approach to characterize water in anodic aluminum oxides

“…The electric field drives cooperative transport of cations (Al 3+ , electrolyte species) and anions (O 2-, OH -, electrolyte species), essential to film growth 16,20,[22][23][24][38][39][40][41] . The porous anodic Al oxide thus formed mainly consists of amorphous, hydrated alumina with additional incorporation of electrolyte anions 31,35,38,[41][42][43][44][45][46] .…”

Formación de películas anódicas en una aleación Al-W: Migración de fósforo

“…La eficiencia del proceso de anodizado, es decir la relación entre el espesor de la película de alúmina formada respecto al espesor del aluminio consumido, y la morfología de los poros se ven afectados por la presencia de dichas especies incorporadas desde el electrolito [7]. El mecanismo de formación de las películas anódicas ha sido recientemente estudiado mediante capas de trazador de una aleación Al-W en un sustrato de aluminio, las cuales son luego incorporadas a la película anódica durante el proceso de anodizado [7], [8] [9]. Los iones de W 6+ migran lentamente hacia la solución a través de la capa barrera de las películas porosas.…”