Optimization of Etching Conditions for Site-Controlled Tunnel Pits with High Aspect Ratios in Al Foil

Abstract

The most appropriate conditions in the site-controlled anode etching of Al using a mask film for the formation of tunnel pits with high aspect ratios over 20 were examined. Anode etching under a reducing current density at an appropriate ratio against time (200mAcm−2normals−1) was effective for the suppression of the undesirable lateral dissolution of the Al surface. Moreover, the addition of a small amount of normalH2SO4 to HCl electrolyte increased the depth of the obtained tunnel pits. By adopting the appropriate anode etching conditions, these improvements could generate site-controlled deep tunnel pits with depths of over 50μm .

Effects of temperature on electrochemical dissolution behavior of aluminum foil

“…A high density of tunnel pits can be generated on aluminum surface by using the DC etching [5][6][7][8][9]. Because the capacitance of the etched aluminum foil is primarily decided by the specific surface area, the distribution and size of the tunnel pits on etched aluminum surface must be generated uniformly to enhance the specific surface area [10][11][12][13][14][15][16][17][18]. The effects of concentration, components, and temperature on the etched tunnel pits have been well investigated [12,[19][20][21][22][23].…”

Optimization of Initiation Sites of Tunnel Pits on Aluminum Foil Using Self-Ordered Concave Structures

“…For example, Nishio et al controlled the initiation sites of tunnel pits by imprinting a thin rubber film with a hole-array configuration onto aluminum surface. 11,12 Masuda et al fabricated highly ordered arrays of etched tunnel pits on aluminum surface by impressing aluminum using a mold with ordered convex structures. [13][14][15] The characteristic of the obtained tunnel pits is mainly decided by that of the printed film or the mold.…”

Use of Colloidal Crystal Templating to Fabricate Ordered Pit Arrays on Aluminum and Aluminum Alloy 3003

“…Utilizing anisotropic anodic etching and PDMS (polydimethylsiloxane) stamps, trench and pit microstructure have been produced on aluminum surfaces (40,41). By applying these stamps, a thin polymer mask with periodic line and space pattern is obtained, that enables selective anodic etching to produce the trench structure.…”

“…Moreover, the addition of small amount of H 2 SO 4 to HCl electrolyte increased the depth of the obtained tunnel pits. With these factors, tunnel pits with depth over 50 µm could be produced (40). Pit morphology from anisotropic anodic etching utilizing PDMS stamps (40).…”

“…With these factors, tunnel pits with depth over 50 µm could be produced (40). Pit morphology from anisotropic anodic etching utilizing PDMS stamps (40).…”