Nanodiamond nanofluid microstructural and thermo-electrical characterization

Abstract This paper describes the microstructural and thermo-electrical properties of diamond nanofluids, which were prepared by dispersing fully functionalized diamond nanoparticles, initially synthesized by the detonation method, into deionized water used as the base fluid in three different concentrations (0.01, 0.1 and 0.25 wt%). The microstructural characteristics of diamond nanoparticles were investigated and analyzed using a transmission electron microscope (TEM) and X-ray diffraction analysis (XRD). Nanofluid particle-size distribution and colloidal solution stability were inspected using dynamic light scattering (DLS) and the zeta potential technique, respectively. The thermal conductivity of the nanofluids was measured in temperatures ranging from room temperature to 60 °C using the transient hot-wire method. The viscosity of the nanodiamond fluids was measured to study their rheological behavior in the same temperature zones at which thermal conductivities were measured. The results indicate up to a 15% enhancement in thermal conductivity with a negligible increase in viscosity. In addition, the electrical conductivity of those nanofluids was measured and compared with literature data. The results show that appropriate functionalization and de-aggregation can minimize the viscosity rise while the thermal conductivity of the base fluid is enhanced with a small amount of nanodiamond additives.