Dry sliding wear behavior of infiltrated particulate reinforced Ni/TiC composites

Abstract

Nickel-Titanium carbide composites are promising candidates for abrasive applications where high electrical and thermal conductivity and good wear resistance are needed. This paper describes the dry sliding wear behavior of a Ni/TiC composite material. The composite with 60 vol% reinforcement was prepared by a liquid infiltration technique, obtaining a continuous matrix material and homogeneous distribution of the reinforcement. The wear behavior of the composite with residual porosity of 1.4% and hardness 49 HRC was investigated under two-body abrasion conditions using a pin-on-ring device with a counterpart ring made of M2 hard steel. An increase in the wear rate was observed when increasing the applied load and the sliding distance, while decreasing at a higher sliding speed. The first part of the wear process is characterized by a tribochemical reaction mechanism by oxidation of the matrix.At higher speed the increase in temperature between the surfaces favors the formation of stable and adherent oxides of the type NiO and likely TiO2 that act as lubricants. Iron oxide is also likely to form due to wear of M2 ring, most likely Fe3O4. The characteristics of the worn surfaces at higher load and lower speed suggest a dominant mechanism of adhesion wear, showing a significant amount of material displaced plastically towards the margin of the wear track. The TiC particles exposed on the composite surface reduce the load to the matrix, decreasing the wear rate of the ductile material.