Investigation of the effects of varying amount of graphene nanoplatelets' (GNPs) addition on carbon nanotubes (CNTs) reinforced boron carbide produced by spark plasma sintering


Balcı E. , Yavaş B. , Göller G.

JOURNAL OF THE AUSTRALIAN CERAMIC SOCIETY, 2021 (Journal Indexed in SCI) identifier identifier

  • Publication Type: Article / Article
  • Publication Date: 2021
  • Doi Number: 10.1007/s41779-021-00635-9
  • Title of Journal : JOURNAL OF THE AUSTRALIAN CERAMIC SOCIETY
  • Keywords: Spark plasma sintering, Boron carbide, Carbon nanotube, Graphene nanoplatelet, MECHANICAL-PROPERTIES, B4C CERAMICS, COMPOSITES, MICROSTRUCTURE, DENSIFICATION, HARDNESS, HYBRIDS, MICROWAVE, TOUGHNESS, METAL

Abstract

In this study, monolithic B4C, B4C-CNT, B4C-GNP, and B4C-CNT-GNP composites were prepared by ultrasonic stirrer with the additions of 3.5 vol.% carbon nanotubes (CNTs) and 0-3 vol.% graphene nanoplatelets (GNPs) and produced by spark plasma sintering (SPS) method. Samples are produced at 1600-1650 celcius sintering temperatures under 40 MPa for 5-min holding time. The effects of GNP addition on the densification behavior, microstructure, and mechanical properties of B4C-CNTs composites were investigated. The sintering temperature was reduced from 1650 to 1600 degrees C with the addition of CNTs and GNPs separately. Sintering temperature was also 1600 degrees C for the all B4C-CNT-GNP composites. The relative density value was 96%, 97.2%, and 98.4% for the monolithic B4C, B4C-CNT and B4C-GNP composites, respectively. The highest relative density value was obtained as a 97.9% by B4C-CNT-GNP composites. The hardness value was 30 GPa, 32.1 GPa, and 35.4 GPa for the monolithic B4C, B4C-CNT and B4C-GNP composites, respectively. The highest hardness value was 32.3 GPa for B4C-CNT-GNP composites. There was an increase in fracture toughness of B4C-CNT composites with the addition of the GNP up to 2 vol.%. The highest fracture toughness was obtained as 6.20 MPa.m(1/2) for the sample containing 2 vol.% GNP. Increase in fracture toughness resulted from the pull-out of GNPs, bridging the cracks and changing the direction of the cracks by GNPs.