Poppy Puspitasari, Dimas Ryan Qomarudin, Sukarni Sukarni, Avita Ayu Permanasari, Jeefferie Abd Razak, Riana Nurmalasari
This study seeks to synthesize and characterize cobalt oxide powder using the sol-gel method to identify the phase, morphology, and distribution of the functional group many applications have been revealed for cobalt oxide nanopowder but the utility of cobalt oxide as heat exchanger nanofluid has not been studied. Therefore, this research is the starting step to make the cobalt oxide nanofluid. The experimental was done by dissolving Cobalt Nitrate Hexahydrate (Co(NO3)2.6H2O) (precursor) into 40 mL of Ethylene Glycol (solvent). The solution was stirred using the stirrer with 200 rpm speed for three hours until it became homogenous. It was blended using a heating magnetic stirrer at 180 ℃ temperature. During this process, the temperature was maintained to be constant to generate gel, for 11 h. After the gel was formulated, the drying process using an oven with 120 ℃ temperature for nine hours was completed. It was followed by the crushing process for one hour. Afterward, sintering processes with time variation of two, four, and six hours, at 500 ℃ temperature was carried out. After the sintering or calcination process, another crushing process was completed for one hour. The synthesis result of Cobalt Nitrate Hexahydrate (Co(NO3)2.6H2O) was characterized using XRD, SEM, and FTIR. The results of phase identification show that all samples have the single phase of Co3O4, reflecting their high purity level with no other polluters. Besides, the sample sintered for four hours demonstrates the tiniest size of 35.4 m. Meanwhile, the results of morphology identification reveal that all Co3O4 samples with sintering process for two, four, and six hours have agglomerated sphere form. The functional group identification results signify that the Co3O4 spinel spectrum appears at 678 cm−1 wavelengths. © 2022, The Author(s), under exclusive license to Springer Nature Singapore Pte Ltd.
Mechanical Engineering Department, State University of Malang, East Java, Indonesia; Center of Advanced Materials for Renewable Energy, State University of Malang, East Java, Indonesia; Engineering Materials Department, Universiti Teknikal Malaysia, Melaka, Malaysia