Permanent magnet materials based on Fe-R-C and Fe-Ti-R alloys (R = rare-earth elements)

Thesis/Dissertation · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5325697

Jang, Taesuk

To develop the two prospective alloy systems of hard magnetic phases, i.e., Fe{sub 14}R{sub 2}C and (Fe,Ti){sub 12}R, the effect of alloying and heat treatment on the magnetic properties was investigated. The high intrinsic coercivity often exceeding 15 kOe in Fe-Dy-C ingots is attributed to both find cells (< 10 {mu}m) of Fe{sub 14}Dy{sub 2}C transformed in the temperature range of 850C to below 1200C and a negligible amount of grain boundary phase. The extremely retarded formation of Fe{sub 14}Nd{sub 2}C in Fe-Nd-C alloys is due to the difficulties in nucleation, and Fe{sub 14}Nd{sub 2}C is much less stable than Fe{sub 14}Dy{sub 2}C so that it forms only in the narrow temperature range between 800C and 900C. The tetragonal (Fe,Ti){sub 12}R compounds are crystallized from the melt via peritectic reactions. The extension of the primary Fe field in Fe-Ti-R is the same as that in Fe-R-C, i.e., it increases in the direction Fy {yields} Ce. In Fe-Ti-Nd and Fe-Ti-Sm, the Ti-stabilized Fe{sub 7}R phase (Hexagonal Cu{sub 7}Tb type) is newly observed. The phase Fe{sub 11} TiR in these systems either is stoichiometric or has a negligible homogeneity range.

• Research Organization: North Carolina State Univ., Raleigh, NC (United States)
• OSTI ID: 5325697
• Country of Publication: United States
• Language: English

Related Subjects

36 MATERIALS SCIENCE
360102 -- Metals &amp; Alloys-- Structure &amp; Phase Studies
360104* -- Metals &amp; Alloys-- Physical Properties
ALLOYS
CARBIDES
CARBON COMPOUNDS
HEAT TREATMENTS
IRON ALLOYS
IRON CARBIDES
IRON COMPOUNDS
MAGNETIC MATERIALS
MAGNETIC PROPERTIES
MAGNETS
MATERIALS
PERMANENT MAGNETS
PHASE STUDIES
PHYSICAL PROPERTIES
RARE EARTH ALLOYS
TEMPERATURE RANGE
TEMPERATURE RANGE 1000-4000 K
TITANIUM ALLOYS
TRANSITION ELEMENT COMPOUNDS