Tribological Characterization of Al₂O₃/TiC/Ni Functionally Graded Materials

Abstract

Symmetrically graded materials in the systems of Al₂O₃/TiC/Ni with three different outer layers of the Al₂O₃, Al₂O₃-15vol%SiC, and Al₂O₃-20vol%a(WC-15wt%Co) were sintered by SHS/HIP. Strong compressive-residual-stresses were induced in the outer layers resulting in enhancement of their surface toughness, hardness and strength. These FGMs showed superior wear resistance comparing with the monolithic Al₂O₃ ceramics. The Al₂O₃-20vol%(WC-15wt%co)/TiC/Ni system showed the lowest friction coefficients of 0.28. However, the friction coefficients of these FGMs increased with temperature and the worn parts were rough.