Detachment of alumina films from aluminium by 100 keV H⁺ ions

Abstract

Irradiation of aluminium covered by anodic oxide films 3-14 nm thick using 100 keV H + ions is shown to result in detachment of the oxide film. A dose of 6.6 × 10 16 H + ions cm −2 on a 6.5 nm thick film causes the removal of large pieces of oxide with dimensions at least 15 µm. Atomic force microscopy analysis shows that the location of the failure is within ∼1 nm of the metal/oxide interface. The large aspect ratio (width to thickness) of the detached pieces is thus ∼2000 : 1 and indicates that there is a disruption of the oxide bonding over large areas. The bombardment also results in the formation of blisters with diameters up to several hundred nanometres in the oxide, accompanied by shallow depressions, ∼5 nm deep in the underlying metal. The detachment is suggested to be associated with either condensation of vacancies generated in the metal by the H + ions or accumulation of hydrogen atoms deposited in the metal by the ion beam in the region of the metal/oxide interface. Although the beam energy and dose were expected to cause some disruption in the implanted material, the complete detachment of large areas of oxide was not anticipated. In fact, this appears to be the first time such gross detachment of an anodic film by H + ion irradiation has been reported.

Impact of Pretreatment of Metal Glass Fe70Cr15B15 on Anodization in 1-butyl-3-methylimidazolium Tetrafluoroborate Ionic Liquid

“…Detachment of the anodic oxide films from the metal surface was observed for aluminum and its alloys, e.g. [24][25][26]. Detachment of the anodic oxide film from the amorphous Fe-alloy was detected for the first time.…”

Analysis of the Extreme Equilibrium Conditions of an Internal Cavity Located Inside a Flat Metal Plate Subjected to an Internal Pressure p

“…In some cases, hydrogen diffusion can produce embrittlement and can be associated with stress-corrosion cracking [6][7][8]. In other cases, hydrogen bubbles can appear; they are cavities below the surface of the material due to excessive internal pressure and can be the origin of hydrogen-induced cracking [9][10][11]. Hydrogen embrittlement commonly occurs in low resistance steels with magnitudes less than 80 ksi of yield strength [12], although there are also cases in aluminum [9][10][11]13].…”

Effect of hydrogen on the integrity of aluminium–oxide interface at elevated temperatures

“…Metals and alloys take up hydrogen during their processing and service, when exposed to humid atmosphere, hydrogen-containing gases or aqueous solutions 1 2 . Hydrogen in these materials can modify several aspects of defect behaviour 3 4 5 that are closely related to failure modes such as hydrogen embrittlement 6 7 8 , cavitation/blistering 9 and interface failure 10 11 12 , and thus greatly undermine the material reliability. Although protective films such as aluminium oxide and chromium oxide are widely adopted as environmental barriers, their protection against hydrogen is incomplete; they may even retard hydrogen effusion and facilitate defect formation, such as dislocation loops, micropores and blisters 12 13 14 15 16 17 .…”