Synthesis and properties of graphene and graphene/carbon nanotube-reinforced soft magnetic FeCo alloy composites by spark plasma sintering

Abstract

The effect of the addition of graphene nanoplatelets (GNP) and graphene nanoplatelet/carbon nanotube (GNT) mixtures on the mechanical and magnetic properties of spark plasma sintered (SPS) soft magnetic FeCo alloys was studied. Three different volume fractions (0.5, 1& 2 vol.%) of GNPs and GNTs were investigated. Ball milling was used to disperse the GNPs in monolithic FeCo powder; while magnetic stirring and ultrasonic agitation were used to prepare hybrid GNT prior to ball milling. The highest saturation induction (Bsat) of 2.39 T was observed in the 1 vol. % GNP composite. An increase in the volume fraction of the ordered nano crystalline structure was found to reduce the coercivity (Hc) of the composites. The addition of CNTs to the GNP composite prevented grain growth, leading to grain refinement. An 18% increase in hardness was observed in the 1 vol. % GNP composite as compared to the as received FeCo alloy. A reduction in tensile strength was observed in all of the composite materials, except for the 0.5 vol. % GNT composite, for which a value of 643 MPa was observed. Raman spectroscopy indicated a reduction in the defect density of the GNPs after adding CNTs.

Enhancement in the elongation, yield strength and magnetic properties of intermetallic FeCo alloy using spark plasma sintering

“…Therefore, improving the ductility and toughness of increase in ductility. The ductility of the samples sintered at 1100 ºC without dwelling is higher than the recently reported ductility of FeCo alloy composites prepared by spark plasma sintering under 80 MPa pressure, at 900 ºC for 3 min [29,33].…”

Mechanical and magnetic properties of spark plasma sintered soft magnetic FeCo alloy reinforced by carbon nanotubes

“…The stress on the surface of the CNTs introduced by the functionalization process may be released by removing defects and oxides from the CNTs. Improvement in quality of carbon nanostructure composite consolidated by SPS has been observed in [37]. CNTs.…”

Structural characterization of semi-heusler/light metal composites prepared by spark plasma sintering

“…Apart from mechanical or thermal properties of composites, more peculiar physical properties can find their use in engineering materials – this might include for instance ferromagnetism, thermoelectric properties or shape memory effect. SPS has been already used for manufacturing of ferroelectric composites 9 , magnetoelectric ceramic composites 10 or soft magnetic composite materials 11 , 12 . The possibilities of mixing a material with a distinct functional property (ferromagnetism, shape memory) with a light-weight metal remain almost unexplored.…”