Characterization of entrapped gases in rapidly solidified powders

✍ Scribed by B.H. Rabin; G.R. Smolik; G.E. Korth

• Book ID: 103951250
• Publisher: Elsevier Science
• Year: 1990
• Tongue: English
• Weight: 632 KB
• Volume: 124
• Category: Article
• ISSN: 0921-5093
• DOI: 10.1016/0921-5093(90)90328-z

✦ Synopsis

Analysis of a variety of rapidly solidified powders produced in inert gas environments revealed that the powders contain inert gas levels on the order of several atomic parts per million. Characterization of a centrifugally atomized type 304 stainless steel powder showed that the gas concentration and porosity increased with increasing particle size owing to the presence of gas bubbles within the powder particles. A mechanism for gas bubble entrapment during fiquid droplet formation and sofidification is suggested. Calculations based upon a spherical fiquid droplet containing a gas bubble indicate that most of the observed gas can be accounted for by the macroscopic gas porosity; however, it is not possible to rule out that a small fraction of the gas may be present in submicroscopic form.