0000000000744642
AUTHOR
M. C. Margaryan
ANNEALING EFFECT ON COERCIVITY AND MICROHARDNESS IN SINTERED (Nd, Tb)15(Fe, Co, Al)78B7 MAGNETS
The variation of the coercivity and microhardness with annealing (475–1150°C/3.6 ks) of sintered (Nd, Tb) 15 (Fe, Co, Al) 78 B 7 permanent magnet have been investigated. The data indicate that the coercivity reaches the mininum and the maximum at 600°C and 775°C, respectively. Optical and scanning electron microscopy and magnetic domain structure observations give no hints to any change in microstructure. Fitting of the Mössbauer spectra of permanent magnets for different coercivity ( i H c ) values revealed that magnetic hyperfine fields (B Hf ) on all Fe sites are reduced with the increase in i H c value and the higher value of the i H c corresponds to the higher value of the Mössbauer l…
Peculiarities of Forming of Magnetic Hardening in Sintered Nd15Fe76.2Ti1.0Al0.8B7 Permanent Magnet by Ageing
Variations of the intrinsic coercivity ( i H c ) with ageing (at 293 to 1173 K for 0.45 to 57.6 ks) of sintered Nd 15 Fe 76.2 Ti 1.0 Al 0.8 B 7 have been investigated. The tests indicated minimum and maximum of intrinsic coercivity ( i H min c and i H max c ) at temperatures 725 K and 1025 K, respectively. The observed behaviour of i H c has been compared with microhardness measurements and microstructure observations (SEM, EDAX, domain structure (DS) and room temperature Mossbauer spectroscopy). SEM and DS investigations gave hints to a change in microstructure. Fitting of the Mossbauer spectra of permanent magnets for different i H c has shown that the magnetic hyperfine field Bhf of 8j2 …