Development of high-coercivity state in melt-spun Fe41Pd41B8Si6P4 ribbons
- 54 Downloads
The phase transformation and magnetic hysteresis properties of melt-spun Fe41Pd41B8Si6P4 ribbons subjected to the annealing at temperatures of 500–550 °C were studied after holding for 0.1–60.0 h by transmission electron microscopy (TEM), X-ray diffraction (XRD) and thermomagnetic analysis. The additions of P, B and Si to the FePd alloy allowed us to achieve the coercivity of 124 kA·m−1, which is 2.6 times higher than that of the melt-spun ribbons of the binary equiatomic FePd alloy. The high-coercivity Fe41Pd41B8Si6P4 alloy is nanocrystalline and is composed of the ordered L10-phase grains approximately 40 nm in size and inclusions of the Fe2(P, B) and Pd2(Si, B) phases. The coercivity kinetics is controlled by the phase transformation which can be divided into three stages: transformation from the bcc structure to nanosized regions of the fcc and Fe2P phases; transformation from the fcc to L10 nanosized regions with somewhat different degrees of tetragonality and their ordering; and extensive growth of the weight fraction of L10 phase from the fcc nanosized regions. P and B atoms occupy interstitial sites in the iron plane of L10 lattice, thus decreasing its Curie temperature (TC).
KeywordsFe–Pd–P–B–Si Melt spinning L10 Nanostructured materials Phase transformation Magnetic measurements
This work was financially supported by the Indian–Russian Collaborative Project (Nos. 17-52-45097 and INT/RUS/RFBR/P-267) and the State Assignment of Ministry of Science and Education of Russia (No. AAAA-A18-118020290129-5). The X-ray diffraction investigation and the magnetic measurements have been performed in the Center of Collaborative Access of IMP UB RAS. The authors gratefully appreciate the help of Dr. Yaron Kauffman and Eng. Michael Kalina from the MIKA center at the Technion—Israel Institute of Technology—for help in samples preparation and conducting the TEM measurements.
- Rodriguez-Carvajal J. Recent developments of the program FULLPROF. Comm Powder Diffr Newsl. 2001;26:12.Google Scholar