Influence of Hardening Additives on the Characteristics of the Tribological TiC–Al2O3 Ceramic Composite Obtained by SHS

Abstract

Addition of various reinforcements was studied in an attempt to produce a TiC–Al2O3 composite with high density, homogeneous microstructure, and outstanding mechanical properties for use in aggressive media using self-propagating high-temperature synthesis (SHS). Ductile Ni-metal powder (5 – 20 wt.%) and Al2O3 and ZrO2 (1 mole fraction) dilutions with and without Ni addition were introduced into TiC–Al2O3 composite synthesized by combined SHS and direct consolidation (DC). The influence of the Ni content and dilution with Al2O3 and ZrO2 on the phase composition, densification behavior, microstructure, and mechanical properties of the synthesized TiC–Al2O3 composite was investigated. The best results were obtained by adding Ni(5 wt.%) to the TiC–Al2O3 composite. However, the chemical reactions between the starting precursors were disturbed and the composite characteristics worsened if the Ni content was increased to >5 wt.%. Accordingly, addition of 5 wt.% Ni was suggested to produce a highly dense TiC–Al2O3 composite with a homogenized morphology and unparalleled mechanical properties. Moreover, the produced composites could be used successfully in aggressive media and tribological applications.