Tribological Properties of WCCo/cBNComposites Produced by Pulse Plasma Sintering

In view of their advantageous properties (high hardness, good frictional wear resistance, chemical and thermal stability at elevated temperatures), cubic boron nitride (cBN) and tungsten carbide (WC) are commonly used for the fabrication of cutting tools.The composites were consolidated at a temperature of 1100 degrees C under a load of 100 MPa for 10 min. The density of the thus produced material was close to the theoretical value (about 99.6%), and the hardness HV30 was about 1950. The phases identified in the composite were WC, Co, and cBN. Microstructural examinations revealed that numerous trans-crystalline fractures through the cBN particles occurred in the material.The present study is concerned with the wear of the WCCo and WCCo/cBN composites. Comparative tribological examinations were performed in a tribological tester using the ball-on-disc arrangement under the conditions of dry friction. The counter-specimens were steel and Al2O3 balls. The tests were conducted under a unit load of 10 N. After the tests, the surface of the samples was examined to describe the wear mechanisms active in various composite materials.