Directional Solidification of Graphene/Paraffm nanofluids assisted by electromagnetic field

摘要

Graphene nanoparticles and sodium dodecyl benzene sulfonate (SDBS) were dispersed in Paraffin by ultrasonic vibration. This nanofluid was then put into a rectangular cavity, and solidified in vertical direction from the bottom to the top. Then, joined electromagnetic field with a electric-field intensity of 110v and a magnetic induction intensity of 0.1T during directional solidification process above, also, a same nanofluid solidification without electromagnetic field for compare Photoes were taken during directional solidification and after solidification to show the interface shape during solidification and the distribution of nanoparticles after solidification. The environmental scanning electron microscope (ESEM) was also used to observe the different distribution of nanoparticles in the vertical direction of solid phase after solidification. It was found that directional solidification without electromagnetic field made graphene nanoparticles distributed to the top area of the solid, particles clustered seriously while they were barely appeared to the bottom area of the solid. The joining of electromagnetic field made them distribute in all area of the solid, dispersed better, particle size also became smaller than that without electromagnetic field, we thought that directional solidification assisted by electromagnetic field broke the force balance of nanoparticles, and particles were more easily to engulfed by solid interface compared to those without electromagnetic field. As a result nanoparticles dispersed better in the solid after solidification.