WEAR OF CYLINDER BORE MICROTOPOGRAPHY

Atomic force microscopy (AFM) reveals additional 3D topography informa tion on tribology surfaces previously measured and evaluated by conven tional 2D stylus technologies. This paper deals with the implications of the more detailed topographical information scanned from cast iron automotive cylinder liners. Worn and unworn surfaces measured both by AFM and stylus techniques were compared visually and quantitatively us ing an effective relocation technique. Quantitative comparison was mad e of 3D and 2D surface parameters, such as root mean square roughness, and slope, significant for the tribological behaviour of the surfaces . The extra surface features found by the AFM measurements (e.g. steep er slopes and more peaks and valleys) significantly change the numeric al values of the roughness parameters, and this scale-dependent differ ence, when compared with conventional stylus-measured parameters, poin ts to the possibilities of deepening the understanding of cylinder lin er lubrication in the light of more finely detailed measurements.