Y. Li et al., COLD SEALING MECHANISM OF ANODIC OXIDE-FILMS ON ALUMINUM .1. COMPOSITION AND STRUCTURE OF COLD-SEALED OXIDE-FILMS, Plating and surface finishing, 80(9), 1993, pp. 79-82
The composition and structure of cold-sealed anodic oxide films on alu
minum formed in sulfuric acid solution were investigated by means of X
-ray diffraction, infrared spectroscopy, thermogravimetry and differen
tial thermal analysis. Oxide films are mainly composed of amorphous al
umina, and also contain sulfate. Boehmite (AlOOH), nickel hydroxide [N
i(OH)2], and aluminum fluoride (AlF3) are formed in cold sealing. Fina
lly, the mechanism of the cold sealing reaction is discussed.