Cold welding behavior of fine bare aluminum powders prepared by new low oxygen induction thermal plasma system.

Abstract A low oxygen induction thermal plasma (LO-ITP) system was developed and a cold-welding behavior of bare fine metallic aluminum powders prepared by the system developed here was observed. This behavior is suitable for a metal precursor for metal matrix composites (MMC) since fine and bare metal particles may contribute to obtaining a well-dispersed state and a high relative density respectively, which lead to the enhancement of the reinforcement of MMC properties. The electric conductivity of the aluminum green pellet compacted at 200 MPa reached 2.9 × 107 S/m, which is comparable to that of bulk aluminum, indicating that the cold welding was taken place since the surface contamination layer such as an oxide may be negligibly thin. Therefore, the powder obtained in this work is expected to be useful in enhancing the reinforcement of MMC properties. Graphical abstract Image 1 Highlights • A new low oxygen induction thermal plasma system was developed. • Bare fine metallic Al powders were successfully prepared. • The electric conductivity of the Al green pellet reached that of bulk Al. • This system can be used as a production process for fine bare metal powders. [ABSTRACT FROM AUTHOR]