Evaluation of thermoacoustics parameters of CoFe2O4–ethylene glycol nanofluid using ultrasonic velocity technique

• Published in: Journal of materials science. Materials in electronics Vol. 30; no. 2; pp. 1175 - 1186
• Main Authors: Kharat, Prashant B., Chavan, Apparao R., Humbe, Ashok V., Jadhav, K. M.
• Format: Journal Article
• Language: English
• Published: New York Springer US 01.01.2019; Springer Nature B.V
• Subjects: Acoustic attenuation; Acoustic impedance; Acoustic properties; Acoustics; Bulk modulus; Characterization and Evaluation of Materials; Chemical precipitation; Chemical synthesis; Chemistry and Materials Science; Cobalt ferrites; Compressibility; Ethylene glycol; Magnetic properties; Materials Science; Nanofluids; Nanoparticles; Optical and Electronic Materials; Organic chemistry; Particle interactions; Relaxation time; Ultrasonic attenuation
• ISSN: 0957-4522; 1573-482X
• DOI: 10.1007/s10854-018-0386-1

Chemical co-precipitation method was employed to synthesize cobalt ferrite (CoFe 2 O 4 ) nanoparticles and to prepare stable nanofluids. The cobalt ferrite nanoparticles and the prepared nanofluids were characterized further for their structural, morphological, elemental, magnetic properties and dispersion stability in order to explore various properties. It shows the prepared CoFe 2 O 4 nanoparticles of spinel structured and 11 nm superparamagnetic, spherical in nature. Finally, CoFe 2 O 4 nanoparticles were dispersed in the ethylene glycol to prepare magnetic nanofluid in various concentrations (0.2%, 0.4%, 0.6%, 0.8%, and 1% by volume). The prepared nanofluids showed highly stable of more than 8 days for 0.2 vol%. The thermo-acoustic studies were carried out at different temperatures ranging from 20 to 80 °C of the nanofluids. Thermo-acoustical properties such as ultrasonic velocity (U), acoustic impedance (Z), adiabatic compressibility (β), bulk modulus (K), ultrasonic attenuation (α), relaxation time (τ), and intermolecular free length (L f ) were estimated and examined in the present work. The thermo-acoustic studies of magnetic nanofluids elaborate deeper understanding of particle–fluid, particle–particle interactions as functions of concentration, temperature. In addition, the paper is intended to formulate a relationship between thermo-acoustic properties and concentration of CoFe 2 O 4 in nanofluids, which would be of great importance to the nanofluids.