The effect of sodium dodecyl benzene sulfonate addition on graphene oxide nanofluids quench medium for medium carbon S45C steel

Graphene oxide (GO) has a high thermal conductivity so that it can be used in heat transfer applications. The example is for nanofluids quench medium. In this study, graphene oxide was characterized using Energy Dispersive Spectroscopy (EDS) and Scanning Electron Microscope (SEM) to determine the chemical content and morphology. GO-based nanofluids were synthesized with concentrations of 0.01%, 0.03% and 0.05% in the water base fluid. Furthermore, the surfactant Sodium Dodecyl Benzene Sulfonate (SDBS) as much as 0%, 3%, 5% and 7% was added. The obtained nanofluids was ultrasonicated for 15 minutes and then tested for thermal conductivity and zeta potential. After that, the nanofluid was used as quenchant for S45C hardening process. The austenization process was done at 900°C for 1 hour. The result showed that higher concentration of GO and surfactant generally lower the thermal conductivity of the nanofluid. The highest thermal conductivity was obtained on 0.01% GO without surfactant at 0.59 W/mK. The conductivity decreased at the highest GO and surfactant addition at 0.57 W/mK. However, the highest hardness achieved was on the 0.05% GO with 5% SDBS at 48 HRC. This result showed that the thermal conductivity of nanofluids quench medium did not directly correlate with the hardness of the quenched samples.