Projects 1999/2000

Surface Roughness and Visual Appearance of Automotive Paint Systems

 The look of a car in the showroom depends on the way that the paint is applied and cured. In general horizontal surfaces look smoother and shinier than vertical surfaces and the appearance depends on the distance from which the surface is viewed. The visual appearance is, in part, a function of the surface roughness of the paint finish . Properties such as gloss or orange peel depend on surface topography with different wavelengths. The objective of this project is to develop a method for assessing the visual appearance of a range of automotive paint finishes and its relationship with surface topography. Traditional solvent borne and more modern high solids and water borne formulations will be compared.

Effect of lubricant additives on fatigue of gear steels

Lubricant additive packages used to reduce scuffing wear in the gearbox are often responsible for an increase in the amount of micropitting and hence reduced gear performance. Micropitting is a surface fatigue failure mode and a previous project has shown that exposure of carburised steel fatigue test pieces to lubricants containing additive packages at temperatures up to 100oC can dramatically reduce the fatigue performance of the material. The objective of this project is to determine the effect of different lubricant additive packages on the rotating bend fatigue performance of a range of surface treated gear steels and to determine which surface treatments are most effective at resisting attack by the lubricant.

Life of heating wires

Thin resistance heating wires are integral parts of many consumer products such as cookers and toasters. When such wires are exposed to high temperatures under oxidising conditions they form an oxide scale which, if the wire material is correctly specified, forms a protective layer on the wire surface that slows further oxidation and prolongs wire life. Such oxide scales fail by either the mechanical stresses generated in thermal cycling (leading to scale spallation) or chemical composition changes reducing the life and protectiveness of the oxide scale. The object of this project is to assess the mechanical and chemical failure mechanisms for a range of different heating wire compositions in order to generate lifetime-prediction maps for the materials.