Centrifugal Atomization of Neodymium and Er3Ni Regenerator Particulate

Abstract

Many applications require reliable, compact cryogenic coolers such as those that operate on the Gifford-McMahon cycle. Recent cryocooler research has concentrated on the use of lanthanide containing materials due to their large heat capacities at low temperatures. A major problem with employing lanthanide metals and compounds in cryocoolers is the difficulty involved in producing sound, spherical particles with low contamination. 1--3 To permit the full realization of the benefits of lanthanide heat exchanger materials, this study addresses the development of a centrifugal atomization apparatus which can produce high quality Er3Ni and Nd powders. The device from which this apparatus evolves has been shown to produce spherical particles with narrow size distributions.4 While our overall efforts include both fabrication and characterization of lanthanide based powders, we have limited this paper to a discussion of the characterization techniques and results.