The Influence of Sample Preparation on SEM Measurements of Anodic Oxide Layers

Abstract Coatings with high wear, corrosion resistance and sliding properties are desirable in tribological applications, especially for oil-free nodes. In order to obtain such coatings on aluminium alloy the anodizing process is one of the methods which is commonly used. In the present research two kinds of anodic oxide layer were prepared. One series of samples comprised amorphous oxide layer Al2O3 obtained on aluminium alloy EN AW 5251. The second one was the composite oxide layer Al2O3 with inorganic fullerene-like tungsten disulfide (IF-WS2). The addition of IF-WS2 to an acid bath is used to reduce the friction coefficient of the oil free friction pair. The aim of the study is the analysis of the surface and fresh cross section of the samples depending on the kind of conductive metal used for SEM examination. Gold and carbon were used in order to prevent the charging of a specimen with an electron beam in the conventional SEM mode. Significant differences in the interpretation of results were found.