Composition and adhesion of protective coatings on aluminum

The composition, structure and homogeneity of oxide coatings formed by the microarc oxidation (MAO) method on aluminum alloy surfaces and possessing s ignificant hardness and heat-resistance up to 870 degreesC were investigate d. On the basis of experimental data obtained by X-ray analysis, EPMA, XPS methods, the conclusions about oxide layers composition formations were mad e. The presence of finely dispersive aluminum oxide as a main component in the coating composition provides the hardness and heat-resistance of the la yer obtained on the aluminum. This layer has a significant adhesion to alum inum substrate. The model ideas concerning construction and reasons of form ation of thin friable top layer have been suggested. (C) 2001 Elsevier Scie nce B.V. All rights reserved.