Open AccessBenefits of rapid solidification processing of modified LaNi{sub 5} alloys by high pressure gas atomization for battery applications
Author(s) -
I. E. Anderson,
V. K. Pecharsky,
Jason Ting,
C. Witham,
R. C. Bowman
Publication year - 1997
Language(s) - English
Resource type - Reports
DOI - 10.2172/348929
Subject(s) - materials science , alloy , metallurgy , annealing (glass) , hydrogen , hydrogen storage , hydride , microstructure , grinding , metal , chemistry , organic chemistry
A high pressure gas atomization approach to rapid solidification has been employed to investigate simplified processing of Sn modified LaNi{sub 5} powders that can be used for advanced Ni/metal hydride (Ni/MH) batteries. The current industrial practice involves casting large ingots followed by annealing and grinding and utilizes a complex and costly alloy design. This investigation is an attempt to produce powders for battery cathode fabrication that can be used in an as-atomized condition without annealing or grinding. Both Ar and He atomization gas were tried to investigate rapid solidification effects. Sn alloy additions were tested to promote subambient pressure absorption/desorption of hydrogen at ambient temperature. The resulting fine, spherical powders were subject to microstructural analysis, hydrogen gas cycling, and annealing experiments to evaluate suitability for Ni/MH battery applications. The results demonstrate that a brief anneal is required to homogenize the as-solidified microstructure of both Ar and He atomized powders and to achieve a suitable hydrogen absorption behavior. The Sn addition also appears to suppress cracking during hydrogen gas phase cycling in particles smaller than about 25 {micro}m. These results suggest that direct powder processing of a LaNi{sub 5{minus}x}Sn{sub x} alloy has potential application in rechargeable Ni/MH batteries