Tribological behaviour of Al2O3/ZrO2-ZrO2 laminated composites

Laminated composites were prepared in the system Al2O3-ZrO2. Starting from sheets produced by tape casting a symmetric structure was obt ained by superimposing alternated layers of Al2O3/ZrO2 composite and ZrO2. Due to the different thermal expansion coefficients and shrinkage of the tw o materials the alumina/zirconia external layers of the samples exhibit a c ompressive residual stress which leads to an improved apparent surface toug hness. The value of this stress was determined by indentation technique. Th e tribological behaviour of the laminated composites and of a stress free m aterial, with the same composition of the external layers. was assessed by Pin-on-Disc method at different loads and sliding speeds. The effect of dif ferences in properties and microstructural features among the different mat erials on wear and friction were determined and discussed. Possible wear me chanisms art: proposed. In spite of the increased surface toughness in the range of the experimenta l conditions considered, the presence of compressive residual stresses at t he surface does not lead to an improvement of wear resistance in the lamina ted structure. (C) 2000 Elsevier Science S.A. All rights reserved.