Formation of anodic films on sputtering-deposited Al-Hf alloys

摘要: Abstract The growth of barrier-type anodic films at high efficiency on a range sputtering-deposited Al–Hf alloys, containing from 1 to 95 at.% Hf, has been investigated in ammonium pentaborate electrolyte. alloys encompassed nanocrystalline and amorphous structures, the latter being produced for 26 61 at.% Hf. Except highest hafnium content, were contained units HfO 2 Al O 3 distributed relatively uniformly through film thickness. Boron species confined outer regions films. boron distributions suggest that cation transport number decreases progressively with increasing concentration films, ∼0.4 alumina ∼0.2 an Al–61 at.% Hf alloy. 3+ 4+ ions indicate their similar migration rates, which correlates similarity energies –O 2− bonds. For alloy ∼95 at.% was largely nanocrystalline, thin layer oxide, non-uniform thickness, surface. formation ratios changed approximately proportion content between values hafnia, ∼1.2 1.8 nm V −1 respectively.