Preparation of self-lubricating Ti(C,N)-based cermets by solid carburization and wear behavior

In this work, self-lubricating Ti(C,N)-based cermets were prepared by solid carburization. The sintered cermets were wrapped by carburizing agent and sintered again at 1440 degrees C with different time. The microstructure and composition of cermets were studied. The wear behavior of cermets containing graphite phase was also evaluated using a block-on-ring tribometer. The results showed that the carbon content increased gradually in binder phase with carburizing time. When the carburizing time was 3 h, the carbon got saturated in binder phase. When the carbon content exceeded the solubility in the binder, excessive carbon precipitated and formed graphite phase. Uniformly distributed graphite clusters formed in cermets after carburization for 4 h. The graphite clusters consisted of flocked graphite particles. With the carburizing time extended to 5 h, the graphite clusters became large and some of them interlaced together. Besides, the wear results indicated that the volume loss of cermets containing graphite phase was half of that without graphite due to the formation of smooth tribofilm on the worn surface of cermets.