Acta Metallurgica Sinica (English Letters) ›› 2019, Vol. 32 ›› Issue (7): 876-886.DOI: 10.1007/s40195-018-0844-z

Special Issue: 2019年复合材料专辑

• Orginal Article • Previous Articles     Next Articles

Enhanced Wear Resistance of Ni/h-BN Composites with Graphene Addition Produced by Spark Plasma Sintering

Jiao Xu 1,2, Dan-Qing Yi 1,2, Qiang  Cui1,2,  Bin Wang1,2()   

  1. 1. School of Material Science and Engineering, Central South University, Changsha 410083, China
    2. Light Alloy Research Institute, Central South University, Changsha 410083, China
  • Received:2018-08-03 Revised:2018-09-18 Accepted:2018-11-13 Online:2018-11-13 Published:2019-06-20

Abstract:

:Ni-based self-lubricating composites containing a fixed amount of hexagonal boron nitride (h-BN) (5 wt%) and different amounts of graphene (0-1.5 wt%) were prepared by ultrasonic dispersion, high-energy ball milling, and spark plasma sintering. The effects of the graphene content on the physical, mechanical, and wear properties of the Ni/h-BN composites were evaluated. These properties were first enhanced with increasing graphene content, reaching optimal behavior for a graphene content of 1 wt%, and then degraded with further graphene addition. Compared to the pure Ni/h-BN composite, the relative density, hardness, and bending strength of the composite with 1 wt% graphene increased by 2.7%, 7.4%, and 6.3%, respectively, while the friction coefficient decreased by 56% to 0.31, and a reduction in wear rate by a factor of 5-15 was observed. The mechanism for improving the wear properties of the composite with added graphene was due to the formation of a graphene lubricating film on the worn surface, which increased the load bearing capacity of the surface and enhanced lubrication during wear.

Key words: Graphene, h-BN, Wear, Ni matrix composites