Preparation of few-layer graphene nanofluids through ball milling and thermal conductivity analysis
In view of the increasing urgent demand of heat dissipation technology for high-frequency electronic devices,in this paper few-layer modified ball milled graphene with different particle sizes was prepare by physical-mechanical means,using natural expanded graphite as raw material,relying on mechanical collision and charge interaction.By changing the grinding time,different concentrations of few-layer graphene nanofluids were gererated through aqueous dispersion technology.The morphology,structure and particle size distribution of the prepared few-layer graphene were characterized by XRD,Raman,TEM and Laser particle size meter.The results showed that the number of the prepared few-layer graphene layers was about 6～7 layers,with small microcrystal size and regular layered structure.The particle size distribution was concentrated around 80 nm and the distribution was uniform.The influence of the few-layer graphene concentration and partical size on the heat-conducting property of the few-layer graphene nanofluids was studied with the help of the self-built thermal conductivity test platform.It was found that the thermal resistance of graphene nanofluids with fewer layers decreased with the increase of mass fraction,and the thermal conductivity was significantly greater than that of the base fluid and increased with the decrease of the particle size of few-layer graphene.The average heat transfer power in heat pipe increases with the increase of mass fraction.The thermal resistance of few-layer graphene nanofluids with particle size of 83.72 nm and concentration of w=0.1％decreased by 10.96％,while the thermal conductivity increased by 27.31％,and the average heat transfer power increased by 193.1％.Therefore,this method will be of important guiding value to the optimization and improvement of the cooling technology of electronic devices and chips in the future.
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