Cryomilling: An environment friendly approach of preparation large quantity ultra refined pure aluminium nanoparticles

The preparation of aluminium nanoparticles in large quantity is a challenge for most of the synthesis processes available. The present investigation reports a top down approach, known as cryomilling to synthesize large quantity of aluminium nanoparticles (Al NPs). The cryomilling is known to be for ultra refinement of particles size as well as suppress of the rate of oxidation during synthesis. Aluminum is a reactive metal and highly prone to oxidization/nitridation in nanoscale. Therefore, a novel cryomill has been used to prepare large quantity Al NPs in which, the powder has been milled at extremely low temperature (<123 K). This technique does not leave any hazardous by-product and is known to be environment friendly. The ultra refined Al NPs are promising candidate for application in various including explosive formulation, nanofluids, pigments, heat shield coating of aircrafts, etc. Thus, the bulk synthesis of Al NPs by cryomilling will satisfy the increasing demands of Al NPs on an industrial scale. The prepared nanoparticles have been characterized by host of advanced techniques to obtain shape, size, dispersion stability, and purity of the Al NPs. The results indicate that it is possible to prepare Al NPs having size ranging from 5 to 15 nm. Additionally, the thermal stability of nanoparticles has been probed and Al NPs have been found to be thermal stable till 150 °C. The results have been discussed using currently available theories.