Effect of the base material condition on the structure and properties of Al2O3 oxide layers

Abstract

The paper presents a new method for modelling oxide layers for tribology related needs. The most recent world trendsin the machine-building sector, in particular with reference to piston machines, are heading towards reducing theirlubrication and cooling. Hence, a question arises, what the upper layer of a ceramic material should be like in order tomaintain low wear and low frictional resistance. An oxide layer for tribological needs has been formed on an AlMg2 alloy asa result of hard anodizing in SAS electrolyte. This electrolyte enables the control of oxide layer production parameters,which allowed obtaining for the tests an oxide coating with a wide range of changes in porosity and micro-hardness μHV.Anodizing has been carried out by means of the direct-current method, using a stabilized feeder, GPR-25H30D, for aconstant electrical charge density of 180 Amin/dm2. A lead plate has been acted as the cathode in the anodizing process. Bymeans of a scanning electron microscope (SEM), the surface morphology and structure, and the chemical composition of thelayers have been analyzed.