Thermomechanical and tribological properties of spark plasma sintered bearing steel/cBN(Ni) composites for engineering applications

Abstract

This study attempt to investigate microstructural, thermomechanical and tribological properties of low-temperature sintered cBN and Ni-coated cBN reinforced bearing steel composites. Ultrasonic probe sonication and spark plasma sintering (SPS) at 900 and 1000 °C were utilized for the dispersion and consolidation, respectively. Findings show that up to 30 wt.% addition of cBN particles, no significant effect on the thermal properties, for the selected sintering temperatures. However, the introduction of Ni-coated cBN reinforcement caused a considerable impact on thermomechanical properties. The developed composites exhibited improved tribological properties as compared to the unreinforced bearing steel. Similarly, samples sintered at a higher temperature of 1000 °C possessed enhanced wear resistance in comparison to samples sintered at 900 °C. Furthermore, Ni-coated cBN reinforced samples exhibited superior wear resistance. However, more than 10wt.% of Ni-coated cBN reinforcement led to material loss, whereby some of the Ni melted out from the consolidated composite during the sintering process.

Keywords

• Bearing steel
• Cubic boron nitride
• Thermal properties
• Tribology
• Metal-matrix composite
• Spark plasma sintering