The structural features of the porous type of anodic oxide coating applied to aluminum have been investigated with the electron microscope. These coatings consist of close‐packed cells of oxide, predominately hexagonal in shape, each of which contains a single pore. Pore size is a function of the electrolyte used and is independent of forming voltage. Wall thickness and barrier thickness are primarily a function of forming voltage and are affected to a minor degree by the electrolyte type. Pertinent dimensions of anodic coatings formed in sulfuric acid, oxalic acid, chromic acid, and phosphoric acid electrolytes are presented, and formulas are given for calculating the cell size and pore volume of these coatings.

No abstract

Successful use of the zinc immersion process for plating aluminum alloys is dependent on the effectiveness of the surface conditioning treatments used prior to the immersion zinc dip. Various conditioning treatments are described for removing constituents that may cause difficulty during plating and for obtaining a uniform and active surface for deposition of the zinc layer, The manner in which the conditioning treatmcnts and variations in the zinc immersion layer may affect the performance of plated aluminum alloys is described.

No abstract

No abstract