Experimental Investigation of Rheological Properties and Thermal Conductivity of SiO(2)–TiO(2) Composite Nanofluids Prepared by Atomic Layer Deposition

In the current research, surface-modified SiO(2) nanoparticles were used upon immersion in an applied base fluid (ethylene glycol:water = 1:1). The atomic layer deposition method (ALD) was introduced to obtain a thin layer of TiO(2) to cover the surface of SiO(2) particles. After the ALD modification, the TiO(2) content was monitored by energy dispersive X-ray spectroscopy (EDS). Transmission electron microscopy (TEM) and FT-IR spectroscopy were applied for the particle characterization. The nanofluids contained 0.5, 1.0, and 1.5 volume% solid particles and zeta potential measurements were examined in terms of colloid stability. A rotation viscosimeter and thermal conductivity analyzer were used to study the nanofluids’ rheological properties and thermal conductivity. These two parameters were investigated in the temperature range of 20 °C and 60 °C. Based on the results, the thin TiO(2) coating significant impacted these parameters.