Composite Materials in the TiN–Cr3C2–C/Matrix System

Abstract

The influence of modifying additions on the strength and tribological properties of titanium nitride composites has been examined. The lowest contact angle (25–30°) is shown by the PG12N-01 alloy, containing chromium, boron, silicon, and carbon. Relatively porousless structures can be produced in the TiN–PG12N-01 system when chromium carbide and carbon are introduced into the composite as graphite, contributing to the formation of TiCN to improve wetting and adhesion. Graphite introduced additionally as an impurity remains after sintering as an individual uniformly distributed phase integrated into the overall composite structure. This graphite can successfully act as a dry lubricant, improving the service characteristics. In addition, it activates sintering of the composite allowing it to become almost porousless. The optimum sintering temperature falls in the range 1450–1500°C depending on carbon and metal matrix contents. The resultant composites have 300–500 MPa strength and 16.1 GPa hardness. The highest strength can be reached through an optimum combination of graphite and PG12N-01 matrix. The mechanical characteristics deteriorate when the amount of these components is higher or inadequate. The antifriction characteristics of the materials have been tested by dry end friction (at a speed of 8 m/sec, 50 MPa pressure in the contact area, and 10 km sliding path) against a 65G steel counterface with 60 HRC hardness: friction coefficient has been found to be 0.27–0.3 and wear resistance 0.2 ± 0.02 μm/km. The developed ceramic materials thus have high strength and antifriction characteristics and can be used in dry friction conditions at high speeds and loads.