Carbide/nitride grain refined rare earth-iron-boron permanent magnet and method of making

Patent · Tue Jan 23 04:00:00 EST 1996

OSTI ID:870261

McCallum, R William ^[1]; Branagan, Daniel J ^[1]

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1. Ames, IA

A method of making a permanent magnet wherein 1) a melt is formed having a base alloy composition comprising RE, Fe and/or Co, and B (where RE is one or more rare earth elements) and 2) TR (where TR is a transition metal selected from at least one of Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, and Al) and at least one of C and N are provided in the base alloy composition melt in substantially stoichiometric amounts to form a thermodynamically stable compound (e.g. TR carbide, nitride or carbonitride). The melt is rapidly solidified in a manner to form particulates having a substantially amorphous (metallic glass) structure and a dispersion of primary TRC, TRN and/or TRC/N precipitates. The amorphous particulates are heated above the crystallization temperature of the base alloy composition to nucleate and grow a hard magnetic phase to an optimum grain size and to form secondary TRC, TRN and/or TRC/N precipitates dispersed at grain boundaries. The crystallized particulates are consolidated at an elevated temperature to form a shape. During elevated temperature consolidation, the primary and secondary precipitates act to pin the grain boundaries and minimize deleterious grain growth that is harmful to magnetic properties.

• Research Organization: Ames Laboratory (AMES), Ames, IA; Iowa State University, Ames, IA (US)
• DOE Contract Number: W-7405-ENG-82
• Assignee: Iowa State University Research Foundation, Inc. (Ames, IA)
• Patent Number(s): US 5486240
• Application Number: 08/232,837
• OSTI ID: 870261
• Country of Publication: United States
• Language: English

Related Subjects

/148/75/419/
alloy
alloy composition
amorphous
amounts
base
base alloy
boundaries
carbide
carbonitride
composition
composition comprising
compound
comprising
consolidated
consolidation
crystallization
crystallized
deleterious
dispersed
dispersion
dynamically stable
earth
earth element
earth elements
earth-iron-boron
elements
elevated
elevated temperature
form
formed
glass
grain
grain boundaries
grain growth
grain size
grow
growth
hard
harmful
heated
hf
magnet
magnetic
magnetic phase
magnetic properties
manner
melt
metal
metal selected
metallic
metallic glass
method
minimize
nb
nitride
nitride grain
nucleate
optimum
particulates
permanent
permanent magnet
phase
precipitates
primary
properties
provided
rapidly
rapidly solidified
rare
rare earth
rare earth-iron
refined
secondary
selected
shape
size
solidified
stable
stable compound
stoichiometric
stoichiometric amount
stoichiometric amounts
structure
substantially
substantially amorphous
temperature
thermodynamically
thermodynamically stable
transition
transition metal
trc
trn
zr