Synergistic enhancing effect for mechanical and electrical properties of tungsten copper composites using spark plasma infiltrating sintering of copper-coated graphene

Abstract

Successful applications of WCu alloys in high voltage electrical switches require their high strength and excellent conductivity. Unfortunately, the strategies for increasing their strength such as doping with fine particles and alloying often significantly decrease their conductivity. In this paper, we developed a new pathway for fabricating WCu alloys using spark plasma infiltrating sintering of copper-coated graphene (Cu@Gr) composite powders. Cu@Gr was found to partially prevent the formation of WC after sintering, and graphene was uniformly distributed on the surfaces of network Cu phases. Electrical conductivity of 38.512 M·S/m, thermal conductivity of 264 W·m−1·K−1 and microhardness of 278 HV were achieved for the sintered WCu composites doped with only 0.8 wt.% Cu@Gr powders, which showed 95.3%, 24.3%, 28% enhancement compared with those from the conventional sintering using the undoped WCu powders.

Formation Mechanism and Cohesive Energy Analysis of Metal-Coated Graphene Nanocomposites Using In-Situ Co-Reduction Method

“…It can be seen that the graphene is made up of a wrinkled and folded membrane. From Figure 9b, the graphene sheets are stacked and agglomerated, probably due to the fact that the monolayer nickel-coated graphene sheets are not completely dried before bonded with the graphene layer, which has also been reported in the literature [16]. EDS elemental mapping of the Ni@graphene is shown in Figure 9c,d.…”

“…An efficient method was proposed to pre-coat the surface of graphene with a layer of metal in order to prevent its agglomeration in the matrix [15,16]. Due to the improved dispersion and good interfacial bonding, thermal energy and electrons can be effectively transferred between graphene and the coated metal and thus the wettability of metal-coated graphene can be significantly improved.…”

Sintering effect on microstructural evolution and mechanical properties of spark plasma sintered Ti matrix composites reinforced by reduced graphene oxides

“…Recently, graphene has been widely used as an excellent reinforcement material for metal matrix composites (MMCs). Previous studies showed remarkable achievements in mechanical properties of Al, Cu, Mg and WCu matrix composites after reinforced with graphene [5][6][7][8][9][10]. For example, tensile strength of Cu matrix composites with an addition of 2.5 vol.% reduced graphene oxide (rGO) prepared by molecule level mixing and spark plasma sintering (SPS) reached up to 748 MPa [11].…”

Influence of Pulse Current Forward-Reverse Duty Cycle on Structure and Performance of Electroplated W–Cu Composite Coatings

“…However, W–Cu composites prepared by liquid-phase sintering or infiltration exhibit inferior compositional uniformity and an undesirable contradiction between density and grain size due to the significant difference in melting points of W and Cu [ 4 , 5 ]. It has been reported that the reduction in the size of W particles or the addition of a small amount of nano-W powder can improve the hardness and conductivity of W–Cu composites [ 6 , 7 , 8 ]. However, with the decrease of W grain size, it is difficult to balance densification and microstructural uniformity.…”