The combined effects of erosion and corrosion can lead to a number of material wastage scenarios in industrial environments. In some cases, for example at high temperatures in fluidized bed environments, the wear may be corrosion dominated where chipping of an oxide scale is the predominant process, while in more aggressive environments such as gas turbine conditions, formation of a protective scale may never occur. Thus, pre-oxidation to form a protective scale or coating of a substrate may be effective in reducing material loss in corrosion-dominated environments since particle energies may be low enough to prevent significant deformation of the underlying surfaces.
A computer model has been developed to simulate the erosion of a preformed scale or a coating on a metal substrate. This model uses computer graphics to demonstrate the sequential stages of erosion-corrosion. By incorporating established erosion and corrosion algorithms to calculate the wastage rate, the surface topography and extent of wear can be shown after exposure to erosion-corrosion conditions of varying severity. Thus, one can extrapolate from this technique whether erosion of oxide or metal is likely to be dominant wastage mechanism.
This model was developed to describe the erosion-corrosion of a preformed oxide scale on a metal and comparisons are made between the erosion results for pre-oxidized surfaces and the graphics after computer simulation of erosion-corrosion. However, since the factors which determine adhesion of a preformed scale may be similar in many respects to those of a coating, the model may equally describe the erosion-corrosion behaviour of a coated metal. Hence, the paper shows the stages of the model development and compares the experimental results with those of the model.
- computer simulation