Effect of Carbon Content on Microstructure and Wear Resistance of Fe-Cr-C/TiCN Composites by Spark Plasma Sintering

Fe-Cr-C/TiCN composites with different carbon contents were prepared via mechanical alloying followed by spark plasma sintering. The effects of carbon black content on the microstructure and wear properties of Fe-Cr-C/TiCN composites were systematically investigated by scanning electron microscopy, X-ray diffraction, Vickers hardness test, and ball-on-disk type tribotest. The results show that the (Cr, Fe)(7)C-3 carbides form in the sintered specimens with 1 wt%similar to 5wt% carbon, but (Cr, Fe)(3)C phases appear when the carbon black content reaches 4wt%similar to 5wt%. Carbon black content plays a significant role in the microstructure uniformity and densification of the Fe-Cr-C/TiCN composites. When the sintering temperature is similar to 1000 degrees C, the relative density of specimen without carbon addition increases from 95.0% to 99.7% of the specimen with carbon addition of 3wt%, indicating that the full densification is realized. High Vickers hardness of 11 940 MPa is achieved for the specimen with carbon addition of 3wt%. Furthermore, adding an appropriate amount of carbon (3wt%) contributes to the excellent wear properties with narrow fluctuation ranges of friction coefficient, suggesting an average friction coefficient of 0.320 and wear rate of 6.8x10(4) mm(3).N-1.m(1).