Peculiarities of the formation of high-coercivity structure of (Sm,Zr)(Со,Cu,Fe)z alloys in varying the (4f-,4d-)/(3d-) element relationship

Processes of the formation of the high-coercivity state of the Sm0.85Zr0.15(C00.702Cu0.088Fe0.210)z alloys with different indices z = 6.0, 6.5, and 6.8, which characterize the (4f-,4d-)-to-(3d-) element ratio, are studied. Correlations between the chemical composition of samples and their microstructure and the coercive force, which is formed in the course of isothermal aging and aging during slow cooling (or stepped annealing), are shown. The interrelation between the high-coercivity state and quantitative relationship (volume fractions) of the main structural components based on the 2:17R and 1:5H phases is discussed. The cellular morphology of the alloy, which corresponds to the high-coercivity state, is shown to form during isothermal aging, whereas the final phase compositions of the main structural components form in a temperature range from the isothermal aging temperature to 400°C upon stepped (slow) cooling or quenching. The magnetic properties of samples in the high-coercivity state are determined by the completeness of phase transformations in the main structural components, which substantially depends on their quantitative relations and the (4f-,4d-)-to-(3d-) element ratio.