Centrifugal Atomization Substrate Quenching Of Rapidly Solidified Particles

A new method combining centrifugal atomization with substrate quenching has been developed for producing rapidly solidified flaky particles. To evaluate the process, commercially pure aluminum powder was produced and characterized. The results show that the particle spectrum is broader than that of conventional centrifugal atomization due to the effect of splat quenching. An increase in the rotational speed of the disk or an increase in pouring temperature result in a decrease in particle size. Most particles have the appearance of bamboo-leaves. Their thickness varies from 10 to 40 mu/m and their aspect ratio ranges from 250 to 700. Microstructures are typified by columnar grains comprised of a microcellular structure. Cooling rate, estimated from She cell size, is > 10(9)K/s on the substrate side and 2x10(6)K/s air side.