Effect of sealing on the morphology of anodized aluminum oxide

•We explored structural change of anodizing aluminum oxide induced by sealing.•All sealing methods decrease pore size as shown by X-ray/neutron scattering.•Cold sealing and hot water sealing do not alter the aluminum oxide framework.•Hot nickel acetate sealing both fills the pores and deposits on air oxide interface.•Samples with hot nickel acetate sealing outperform other sealing methods.