Synthesis and Characterization of Ultra Fine Al-cu Powder Particles and Subsequent Dispersion for Heat Transfer Applications

Abstract

In recent years, fluids containing suspension of nanometer-sized particles (nano fluids) have been an active area of research due to their enhanced thermal conductivity over the base fluids. This makes them very attractive as heat transfer fluids in many applications such as coolants in the automobile and electronics industries, and manufacturing processes. Stable nano fluids are being investigated for numerous applications, including cooling, manufacturing, chemical and pharmaceutical processes, medical treatments, cosmetics, etc. In a better description, nano fluids are engineered colloidal suspensions of nano particles (<100 nm) in a base fluid. Common base fluids include de-ionized water and organic liquids.


In this investigation, the two step method of synthesis of ultra fine Al-Cu alloy powder particles and stable dispersion in base fluid is done. Ultrafine powders were prepared by milling elemental Al and Cu powders for 50 hours in a planetary mill. Aiming at the dispersion of nano-Al-Cu is regarded as the guide of heat transfer enhancement, the stability of Al-Cu alloy particles in de-ionized water were studied under different pH values by using nano zeta meter.

It is found from XRD that the crystallite size is around 7 nm and lattice strain value is around 1.4 % for Al-Cu. After 50 hours of milling, particles size has been reduced from 28 m to 300 nm. Transmission electron microscopy (TEM) shows that each particles consists of large number of crystallites of size around 10-15 nm. The stability of nanofluids was also studied by nano zeta meter at different pH of nanofluids for constant ultrasonication time and magnetic stirring. It has been found from Nano zeta meter that the suspension is best stable at pH value of 9.5 corresponding to zeta potential value of -90.60 for Al-Cu alloy with the presence of surfactant.