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Title: Solid State Processing of High-Pressure Gas Atomized Powders to Create Near-Net-Shape Alnico-Based Permanent Magnets

Authors:
; ; ; ;
Publication Date:
Research Org.:
Ames Laboratory (AMES), Ames, IA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1371935
Report Number(s):
IS-M 1043
DOE Contract Number:
DE-AC02-07CH11358
Resource Type:
Conference
Resource Relation:
Conference: Powdermet 2016 Boston, MA 2016
Country of Publication:
United States
Language:
English

Citation Formats

Kassen, Aaron, White, Emma, Palasyuk, Andriy, Zhou, Lin, and Anderson, Iver. Solid State Processing of High-Pressure Gas Atomized Powders to Create Near-Net-Shape Alnico-Based Permanent Magnets. United States: N. p., 2016. Web.
Kassen, Aaron, White, Emma, Palasyuk, Andriy, Zhou, Lin, & Anderson, Iver. Solid State Processing of High-Pressure Gas Atomized Powders to Create Near-Net-Shape Alnico-Based Permanent Magnets. United States.
Kassen, Aaron, White, Emma, Palasyuk, Andriy, Zhou, Lin, and Anderson, Iver. 2016. "Solid State Processing of High-Pressure Gas Atomized Powders to Create Near-Net-Shape Alnico-Based Permanent Magnets". United States. doi:. https://www.osti.gov/servlets/purl/1371935.
@article{osti_1371935,
title = {Solid State Processing of High-Pressure Gas Atomized Powders to Create Near-Net-Shape Alnico-Based Permanent Magnets},
author = {Kassen, Aaron and White, Emma and Palasyuk, Andriy and Zhou, Lin and Anderson, Iver},
abstractNote = {},
doi = {},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2016,
month = 7
}

Conference:
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  • The 2011 price shock in the rare earth (RE) permanent magnet (PM) marketplace precipitated realization of extremely poor RE supply diversity and drove renewed research in RE-free permanent magnets such as “alnico.” Essentially, alnico is an Al-Ni-Co-Fe alloy with high magnetic saturation and T C, but low coercivity. It also was last researched extensively in the 1970’s. Currently alnico “9” magnets with the highest energy product (10MGOe) are manufactured by directional solidification to make highly aligned anisotropic magnets. This work developed novel powder processing techniques to improve on unaligned anisotropic alnico “8H” with elevated coercivity. Gas atomization was used tomore » produce pre-alloyed powder for binder-assisted compression molding of near-final shape magnets that were vacuum sintered to full density (<1% porosity). Biased grain growth with resulting grain alignment was achieved during a second solution annealing step, during which a uni-axial stress was applied along the axis parallel to the magnetization direction. Lastly, evaluation of heavily stressed samples (>250g) showed reduced overall loop squareness compared to unaligned (equiaxed) 8H due to grain rotation-induced misalignment, while low stresses improved squareness and greatly improved alignment compared to equiaxed magnets, with squareness approaching 0.30 and remanence ratio as high as 0.79.« less
    Cited by 1
  • The 2011 price shock in the rare earth (RE) permanent magnet (PM) marketplace precipitated realization of extremely poor RE supply diversity and drove renewed research in RE-free permanent magnets such as “alnico.” Essentially, alnico is an Al-Ni-Co-Fe alloy with high magnetic saturation and T C, but low coercivity. It also was last researched extensively in the 1970’s. Currently alnico “9” magnets with the highest energy product (10MGOe) are manufactured by directional solidification to make highly aligned anisotropic magnets. This work developed novel powder processing techniques to improve on unaligned anisotropic alnico “8H” with elevated coercivity. Gas atomization was used tomore » produce pre-alloyed powder for binder-assisted compression molding of near-final shape magnets that were vacuum sintered to full density (<1% porosity). Biased grain growth with resulting grain alignment was achieved during a second solution annealing step, during which a uni-axial stress was applied along the axis parallel to the magnetization direction. Lastly, evaluation of heavily stressed samples (>250g) showed reduced overall loop squareness compared to unaligned (equiaxed) 8H due to grain rotation-induced misalignment, while low stresses improved squareness and greatly improved alignment compared to equiaxed magnets, with squareness approaching 0.30 and remanence ratio as high as 0.79.« less
  • Cited by 1
  • We present economic uncertainty in the rare earth (RE) permanent magnet marketplace, as well as in an expanding electric drive vehicle market that favors permanent magnet alternating current synchronous drive motors, motivated renewed research in RE-free permanent magnets like “alnico,” an Al-Ni-Co-Fe alloy. Thus, high-pressure, gas-atomized isotropic type-8H pre-alloyed alnico powder was compression molded with a clean burn-out binder to near-final shape and sintered to density >99% of cast alnico 8 (full density of 7.3 g/cm 3). To produce aligned sintered alnico magnets for improved energy product and magnetic remanence, uniaxial stress was attempted to promote controlled grain growth, avoidingmore » directional solidification that provides alignment in alnico 9. Lastly, successful development of solid-state powder processing may enable anisotropically aligned alnico magnets with enhanced energy density to be mass-produced.« less
  • The effect of temperatures up to 600 d C and the combined effect of temperature and vibration on the magnetic performance of Alnico V and Alnico VI magnet were investigated. (auth)