Rapidly solidified alloys of iron rare earth boron for permanent magnets

Thesis/Dissertation · Tue Jan 01 00:00:00 EST 1985

OSTI ID:5851810

Overfelt, R A

Effects of composition and processing variables on the magnetic properties of rapidly solidified Fe-RE-B were explored using a vibrating sample magnetometer. Additionally, supporting microstructural analyses are given to help explain the observed variations. This work has concentrated on producing large intrinsic coercivities, i.e., greater than about 10 kOe, directly at controlled solidification rates in melt spinning. Intrinsic coercivities of only 100-1000 Oe are obtained at the lowest (0-4 m/s) and highest (40-80 m/s) wheel surface speeds in all alloys investigated. Intrinsic coercivities over 20 kOe were obtained at intermediate wheel surface speeds (20-30 m/s) in alloys of Fe/sub 76/R/sub 16/B/sub 8/, where R is Pr or Nd. Typical hysteresis loops are also given. Substituting Sm and Ce for Pr and Nd does not lead to large intrinsic coercivities at all wheel surface speeds. Replacements of boron with the metalloids carbon or silicon are also ineffective in producing large intrinsic coercivities. The phase responsible for the large coercivities was identified as a tetragonal phase with a = 0.881 nm and c = 1.178 nm. The Curie temperature of the phase is shown to be about 285/sup 0/C. Moderate substitutions of Co for Fe in alloys based on (Fe/sub 100-x/Co/sub x/)/sub 76/Pr/sub 16/B/sub 8/ are shown to significantly raise the Curie temperature of the tetragonal phase and produce corresponding increases in the temperature coefficients of remanence and coercivity.

• Research Organization: Vanderbilt Univ., Nashville, TN (USA)
• OSTI ID: 5851810
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
BORON ALLOYS
MAGNETIC PROPERTIES
IRON ALLOYS
NEODYMIUM ALLOYS
PERMANENT MAGNETS
PRASEODYMIUM ALLOYS
CARBON ADDITIONS
CERIUM ADDITIONS
COERCIVE FORCE
CURIE POINT
SAMARIUM ADDITIONS
SILICON ADDITIONS
SOLIDIFICATION
ALLOYS
CERIUM ALLOYS
MAGNETS
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RARE EARTH ADDITIONS
RARE EARTH ALLOYS
SAMARIUM ALLOYS
SILICON ALLOYS
THERMODYNAMIC PROPERTIES
TRANSITION TEMPERATURE
360104* - Metals & Alloys- Physical Properties