Influence of residual stresses on the wear behavior of alumina/alumina-zirconia laminated composites

Symmetric structures of laminated ceramic composites were produced by superimposing alternating layers of Al2O3 and Al2O3/ZrO2 composite prepared by tape casting. The composites were designed to have an alumina surface layer on either side. This configuration caused residual compressive stresses to be induced on the surface due to the different thermal expansion coefficients of the various layers, leading to an increase in the apparent surface toughness. The amount of residual stress was determined using the indentation technique. The tribological behavior of these laminated structures was evaluated using the pin-on-disk method for different loads and sliding speeds. Comparison with the results obtained from stress-free alumina showed that, within the range of these experimental conditions, the improvement in surface toughness leads to a reduced friction coefficient and increased wear resistance of the composites. Possible wear mechanisms are proposed.