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Contemporary research methods are used to study in detail the structure and phase composition of the (Sm, Zr)(Co, Cu, Fe)z alloys with z = 5.5–7.0 in the as-cast state and after heat treatment, which includes the solid-solution treatment at 1150–1180°C for 5 h, subsequent water quenching, isothermal aging at 800°C for 20 h, and cooling (stepped aging) from 800 to 400°C at an average rate of 100°C/h. The transformation scheme of boundary structural constituent of a (Sm, Zr)(Co, Cu, Fe)z permanent magnet manufactured by powder metallurgy technology is proposed for different heat treatment stages. The formation mechanism of the high-coercivity state of a permanent magnet in the course of complete cycle of heat treatments is given in the form of a sequence of phase transformations accompanied by the redistribution of a number of constituents of the (Sm, Zr)(Co, Cu, Fe)z alloy. [ABSTRACT FROM AUTHOR]

Hard magnetic (Sm,Zr)(Co,Fe,Cu)z alloys intended for application as powder fillers in bonded magnets are considered. The microstructure and intrinsic coercive force of Sm0.87Zr0.13(Co0.702Cu0.088Fe0.210)6.7, Sm0.81Zr0.19(Co0.702Cu0.088Fe0.210)6.3, and Sm0.85Zr0.15(Co0.690Cu0.070Fe0.240)6.8 alloys, the structural and magnetic states of which are formed at different aging temperatures and cooling rates, are studied. A high coercive force and adequate squareness of the magnetic hysteresis loop of the alloy powders under study are observed at grain and subgrain sizes of the 2 : 17 phase of 10–20 μm. It is shown that the anisotropic powders of the Sm0.87Zr0.13(Co0.702Cu0.088Fe0.210)6.7 alloy can be prepared for manufacturing bonded magnets with a coercive force of 14–20 kOe or higher, which are intended for application in electric machines. [ABSTRACT FROM AUTHOR]

In present study, X-ray diffraction and local electron probe microanalysis are used to identify microstructural and phase features of as-cast (Sm,Zr)(Co,Cu,Fe)z alloys used for manufacturing high-coercivity permanent magnets. The structure of the as-cast alloys, which were prepared in the wide composition range corresponding to the coexistence of the 2:17 and 1:5 phases, is studied in detail. The 2:17R, 1:7H, 1:5H, 5:19R, 2:7R, 2:7H, 1:3R, and 1:3H phases were identified and are shown to be simultaneously present in the as-cast state owing to the nonequilibrium phase transformations occurred upon solidification of the ingots. [ABSTRACT FROM AUTHOR]

We show here that palladium-lutetium foil Pd–11.2 wt % Lu membrane can be efficiently used for hydrogen separation via its diffusion at temperatures 300–500°С. Several correlations of the membrane structure morphology and the specific permeability of the membranes are considered. Particular attention is placed in analysis of the membrane surface studied by atomic force microscopy using the phase contrast mode. The studies performed are addressed the problem of the membrane durability for the cyclic operation up to 40 h in hydrogen atmosphere. [ABSTRACT FROM AUTHOR]

(Sm,Zr)(Co,Cu,Fe)6.0–6.8 alloys are prepared by vacuum induction melting and subsequently subjected to heat treatment in order to form a high-coercivity state, which includes annealing at 1160–1180°C for 5 h, quenching to room temperature, isothermal aging at 800°C for 20 h, and subsequent stepped tempering from 800 to 400°C at an average cooling rate of 100°C/h. The morphology and composition of main structural constituents of the alloys are studied by electron microscopy using samples in the form of individual grains separated from ingots. The hysteretic properties of the (Sm,Zr)(Co,Cu,Fe)z samples in the high-coercivity state are shown to correlate with the volume fractions of their main structural constituents, which, in turn, are controlled by the ratio of the 4f-/4d-/3d-element contents in the chemical composition of the alloy. [ABSTRACT FROM AUTHOR]

The purity of hydrogen, which is an alternative energy carrier in powder sources of distributed energy resource systems and, in particular, is the feed stock for fuel cells, should be no less than 99.9999 vol % purity High-purity hydrogen can be prepared only via its separation as a result of selective diffusion through metallic membranes manufactured from specific membrane palladium-based alloys prepared in the form of thin foils. In the present work, the combination of deformation and annealings under different conditions is used to prepare the Pd–7.70 wt % Lu alloy in the form of foil 50 µm thick, whose specific hydrogen permeability is studied in the course of cyclic heating and cooling in a hydrogen atmosphere in a temperature range of 300–500°С. The Pd–7.70 wt % Lu membrane is shown to demonstrate high and stable hydrogen permeability. The evolution of the surface structure of the membrane in the course of its operation in the hydrogen atmosphere is studied by atomic force microscopy using the phase contrast mode. [ABSTRACT FROM AUTHOR]

Correlation between the morphology, magnetic properties of powdered (Sm, Zr)(Co, Cu, Fe)z alloy, and magnetic characteristics of magnets made of these powders has been established. Monotonic variations of average particle sizes and density of ready-made magnets as a function of alloy milling time in a planetary mill have been detected; it has been demonstrated that the dependences of the main magnetic properties of magnets on this variable are characterized by an extremum corresponding to the optimum time of powder milling. The interrelation between average particle sizes, their morphology, and magnetic properties of the powder and magnets made of this powder has been analyzed with consideration for the influence of subsequent sintering of initial powders. [ABSTRACT FROM AUTHOR]