Different stages of aluminium anodization studied with depth profiling techniques

Development and application of a holistic model for the steady state growth of porous anodic alumina films

“…Hence, the number of pores, nucleated towards the end of the first transient stage 0A in Fig. 1 [13,[21][22][23], developed and ordered during the second transient stage AB in Fig. 1 [8,[24][25][26][27][28][29][30][31], rises with both t ca in these stages and the dissolving ability of electrolyte or its ability to solvate ejected Al 3+ .…”

“…1. Three successive stages are apparent: (i) The step 0A of abrupt almost linear rise of V, corresponding to the initial transient stage of flat barrier layer growth in the last range of which the porous structure is nucleated [13,[21][22][23]; it was short enough, of the order of 1 s, and thus it is not easily detected in Fig. 1, however, its detailed separate presentation is unnecessary as there is most interest for the steady state (BC).…”

The origin of nucleation and development of porous nanostructure of anodic alumina films

“…The embryo of porous structure observed in steady state appears in the above noted first transient stage [9][10][11][12][13] and is integrated in the second one. The elucidation of phenomena in transient stages for one step single anodising is of crucial importance since these definitely determine sequential phenomena, the mechanism, kinetics and related parameters for film growth in steady state and thus the design of porous structure.…”

“…for sulphuric, phosphoric and oxalic acid electrolytes, by a transient stage, where a flat barrier layer is formed on the surface of which pores are later nucleated towards its end [9][10][11][12][13], followed by another transient stage where pores are developed and organized yielding the characteristic structure of these films [5,[11][12][13][14][15][16][17][18][19][20][21] that is finally followed by the steady state one. The steady state structure of films is characterized as a close-packed array of approximately hexagonal, columnar cells, each of which contains an elongated, roughly cylindrical, pore normal to the surface extending between the film's external surface and the Al 2 O 3 |Al interface, where it is sealed by a thin, compact, hemispherical shell shaped barrier type oxide layer with thickness roughly around 1 nm per V of applied voltage [22][23][24].…”

“…The nucleation of pores during the transient stages has been studied focusing mainly on the elucidation of the range of transient stages where pores nucleate and progress and on the related structural characteristics [9][10][11][12][13]. However, the origin of emergence of pores nuclei and their progress to completion as pores are still basically unknown.…”