Porous Ni-Co-Cu alloys were fabricated by eliminating Zn from the as-cast precursor alloys using vapor phase dealloying method. The XRD studies point out the formation of several FCC solid solutions of TM with a small amount of ZnO. Fabricated multicomponent porous alloys have an open spongy microstructure that was formed throughout the entire depth of the precursor alloys during VPD. The results of electro catalytic activity studies using linear sweep voltammetry methods indicated that fabricated porous materials with high Ni content demonstrate better activity in both the Hydrogen evolution reaction (HER) and the Oxygen evolution reaction (OER).

In this work, the formation of arrays of tin nanorods by rapid solidification of Sn-Zn alloys followed by selective chemical or electrochemical etching was investigated. Alloys with compositions close to the eutectic point were quenched from the melt using planar flow casting under different cooling conditions. X-ray diffraction and field emission scanning electron microscopy revealed that hypoeutectic alloys form porous structures as a result of zinc dissolution, while eutectic and hypereutectic compositions yield ordered tin nanorods aligned along the heat flux direction. The dimensions of the rods were found to depend on the cooling rate and substrate temperature, with finer and more ordered arrays obtained under rapid crystallization and higher thermal gradients. These results demonstrate that controlled rapid solidification followed by selective etching enables the scalable synthesis of ordered metallic nanorod arrays with tunable morphology.

Electrical resistivity of the nanocomposites Sn 96.5 Ag 3 Cu 0.5 and Sn 95,5 Ag 3,8 Cu 0,7 lead-free solder alloys with minor admixtures of carbon nanospheres (0.05 wt%) was measured in a wide temperature range, including a melting-solidification region. Influence of the carbon nanospheres content on electrical resistivity values has been analyzed. Carbon nanospheres were obtained by electrical discharge method from diesel fuel, cyclohexane, and aviation kerosene. The matrix samples were produced by planar flow casting technique in the form of thin ribbons. Electrical resistivity measurements were performed using four-probe method. Hysteresis between the heating and cooling electrical resistivity curves relates to the non-equilibrium solidification.

According to the well-known concept of multicomponent high-entropy alloys, high entropy of mixing can stabilize the formation of solid solutions (simple bcc or fcc crystal structure) during solidification. Stabilization of the solid solution and prevention of the formation of intermetallic phases during solidification is provided by the high entropy of mixing in the solid and liquid states. High-entropy alloys have increased strength, high hardness, thermal stability in combination with good resistance to oxidation and corrosion. These properties allow to significantly expand the scope of these alloys. In this work, the electrical resistivity, thermoelectric power and surface tension of binary Cu–Sn, Cu–Ga and Cu–Bi alloys, which are the sub-system components of model low-temperature high-entropy Bi–Cu–Ga–Pb–Sn alloys, have been studied in a wide temperature range including solid and liquid states. The lack of the surface tension data of the above-mentioned alloys is compensated by the model predicted values.

The effect of adding Cu on magnetic characteristics of the rapidly quenched alloy (Fe75Co10B15) Cu-100-x(x) with x= 0 and 1.5 at % in amorphous and nanocrystalline state has been investigated. The results of XRD measurements confirmed the nanocrystalline structure with bcc-Fe(Co) phase for both investigated alloys after isothermal annealing at various temperatures. The addition of Cu to the FeCoB alloy has a significant effect the achieved degree of the nanocrystallization and on the soft magnetic properties of the compared alloys. Annealing in vicinity of the first onset crystallization temperature has the advantage of increasing the saturation magnetic polarization to 2 T for Cu-free nanocrystalline alloy while the coercivity is relatively increased. The lowest coercivity of 25 A/m was measured for Cu of 1.5 at % alloy annealed at 420 degrees C for lower time (30 seconds), it achieved the saturation J(s) = 1.84T.

The development of porous materials based on 3d-transition metals (TM), which are abundant and substantially cheaper in comparison with noble metals, is highly desirable for electrocatalyst applications. Porous metals and (more importantly) porous multicomponent alloys regardless of components' chemical activity can be fabricated by the vaporphase dealloying (VPD) method, which is based on the selective removal of a component with a high partial vapor pressure (usually Zn) from an alloy precursor. This method has been applied to fabricate porous Co-Ni-based alloys using asquenched (Co4Cu)(5)Zn-21, (Co3NiCu)(5)Zn-21, (Co2Ni2Cu)(5)Zn-21, (CoNi3Cu)(5)Zn-21 and (Ni4Cu)(5)Zn-21 precursor alloys. It may be noted that adding Cu to precursor alloys results in their considerably better ductility. The SEM micrographs of the fabricated porous alloys revealed a spongy microstructure with large (500 nm) and small (less than 200 nm) pores. The specific surface area of porous alloys calculated according to the multi-point BET method using data from the N-2 adsorption/desorption experiment was in the range of 3 to 17 m(2)/g. XRD analysis of the precursor as-cast ribbons showed that their microstructure is very complex based on e-CuZn5, Co3Zn17, CoZn13, and Ni3Zn22 intermetallic compounds. XRD investigations indicate the formation of two solid solutions with FCC structure during VPD treatment of Co-Cu-Zn and Co-Cu-Ni-Zn precursor alloys. In the case of the VPD treatment of the Ni-Cu-Zn as-cast ribbon, a single-phase FCC solid solution was formed. The XRD analysis has also revealed that the surface of fabricated porous alloys is covered by ZnO. The results of the study of the electrocatalytic activity of prepared porous alloys in the..R and OER reactions indicated that the best activity was demonstrated by porous alloys, where the main component is cobalt with low nickel content.

Alloys with composition Fe80_xCu1B11P4Si4+x (x = 0 and 4), i. e. with Si 4 at % or 8 at % have been prepared by rapid quenching from the melt in air. For comparison the alloy with P 3 at % and Si 8 at % has been investigated as well. As -quenched structure of all ribbons was checked by X-ray diffraction. Subsequently the samples were submitted to thermal analysis, scanning and transmission electron microscopy and magnetic measurements. Hysteresis loops of strips after short-term annealing at 400, 420 and 500 C-o for 5 min changed their shape - the saturation magnetic polarization increased. Its value changed from 1.67 to 1.74 T depending of the crystalline volume fraction for Fe80Cu1B11P4Si4 alloy. Addition of Si to the studied P 4 at % alloy leads to a decrease of coercivity after short-term annealing at the temperatures below the onset of the first transformation. Magnetic work decreased several times and its orientation acquired the distinct orientation along the ribbon axis.

The effect of Si on magnetic properties of the rapidly quenched alloys Fe82−xCu1B10P3Si4+x with x= 0 and 4 at % after short-term annealing (duration 5 minutes) has been investigated. Different Si content showed a significant effect on the magnetic properties and the microstructure after short-term annealing. Annealing at the temperature of the first onset of crystallization has the advantage of increasing the magnetic saturation while the coercivity is significantly lower for Si 8 at % than Si 4 at % alloy. The results of XRD and TEM measurements confirmed the nanocrystalline structure with bcc-Fe phase for both investigated alloys after short-term annealing. Analysis showed the smallest average grain size 20 nm for Si 8 at % sample annealed at 500°C. The upright shape of the hysteresis loops was already evident after lower temperature annealing, while the highest saturation magnetic polarization is most pronounced after 500° C annealing. The best saturation magnetic polarization values of 1.70 T were observed for the nanocrystalline alloy containing 4 at % Si.

Samples of nominal chemical composition Fe81Sn7B12 were prepared by planar flow casting in the form of ribbons approximately 20 mu m thick and 6 mm wide. Crystallization process was followed by differential scanning calorimetry. Alloy exhibits two stages of crystallization. Kissinger equation was used to determine activation energies of both first and second stages of crystallization. Samples were isothermally annealed for 30 min at selected temperatures and annealed in linear heating regime with heating rate of 20 K/min from room temperature up to selected temperatures. Changes in microstructure and magnetic properties were studied by x-ray diffraction and vibrating sample magnetometer.

The structure and magnetic properties of Mn2FeSi alloy as a prospective Heusler material are studied from the viewpoint of the rapid solidification technology used for its preparation. The planar flow casting leads due to fast cooling of the melted material to formation of ribbons with different structural and physical properties. In present study, the crystalline ribbon-type samples are produced and subjected to detail analysis using electron microscopy, positron annihilation spectroscopy, X-ray diffraction, as well as magnetic and Mo & BULL;ssbauer measurements. It is shown that the as-prepared Mn2FeSi ribbon is paramagnetic at room temperature and adopts a cubic structure with lattice parameter of 0.567 nm and Ne & PRIME;el temperature of antiferromagnetic/paramagnetic transition around 45 K. The presence of other phase(s) observed at low temperatures is reflected also in changes of the structural and physical properties after sample annealing at 773 K for 100 h. The results of microstructure, magnetic, and phase composition observations are completed by the positron life time measurements suggesting single vacancies as the main defects in which the positrons are trapped.

Microstructural and magnetic properties of the Mn 2 FeSi Heusler alloys prepared in the bulk and ribbon form have been investigated. Button- and cylinder-shaped ingots produced by arc and induction melting, respectively, were cut to 500 mm thick discs and mechanically and chemically machined, while 25 mm thick and 2 mm wide ribbons prepared by planar flow casting were analyzed in an as-produced state. Despite the differences in the grain size, discs ≈ hundreds of mm and ribbons ≈ 10 mm, the EDX chemical area analyses resulted in the same composition of all samples in a good agreement with the nominal one. The X-ray diffraction patterns have shared the reflections corresponding to both inverse XA and regular L 2 1 cubic structures. Their analysis resulted in the lattice parameters 0.5684(2) nm and 0.5691(3) nm for the disc-type and 0.5672(4) nm for ribbon-type samples. The EDX chemical analysis of the precipitates at the surfaces of disc-type samples yielded slightly higher Mn content at the expense of Si. The flat circular objects observed at the surface of the ribbon were identified as oxides rich in Mn. From the magnetic viewpoint, all samples are paramagnetic at room temperature and transform into antiferromagnetic state at the Néel temperatures 50 K and 40 K for discs- and ribbon-type samples, respectively. The negative Curie temperatures determined at all samples by Curie-Weiss law indicate an antiferromagnetic ordering of spins. Different production technologies are reflected in slightly different results of positron lifetime and coincidence Doppler broadening measurements. Both techniques revealed the monovacancies as the main open volume defects present in all studied samples. The experimental positron lifetimes at defects in the range 162-165 ps agree well with the results of theoretical calculations. First-principles calculations further suggest that there are also antisites defects in large concentrations.

In present work amorphous alloys Co48Fe25Si4B19Nb4-R (R = Nd, Sm, Tb, Yb) were obtained by planar flow casting in the form of ribbons with 3-5 mm wide and 35-45 μm thickness. It was found that crystallization process goes into two stages and depends on the used rare-earth addition and its content in the alloy by differential thermal analysis method. Glass-forming ability criteria were calculated. It is shown that paramagnetic Curie temperature of alloys in liquid state can be used as their a-priori criterion of glass-forming ability.

Crystallization kinetics of rapidly quenched Fe-Sn-B alloys under non-isothermal conditions were studied using differential scanning calorimetry. Formation of crystalline phases was analyzed by X-ray diffraction. Nominal chemical compositions were Fe81Sn7B12, (Fe3Co1)81Sn7B12 and (Fe81Sn7B12)99Cu1. Alloys were prepared by planar flow casting in the form of ribbons approximately 20 mu m thick and 6 mm wide. Mechanism of crystal-lization was studied under framework of the Johnson-Mehl-Avrami-Kolmogorov model. Alloys exhibit two stages of crystallization. Results show decrease in activation energy of the first stage of crystallization with addition of Cu and increase with addition of Co. Crystallization mechanism of the first stage of crystallization for Fe81Sn7B12 and (Fe81Sn7B12)99Cu1 alloy starts as growth with increasing nucleation rate and continues as growth with decreasing nucleation rate. Addition of Co changes mechanism of crystallization. Which in case of (Fe3Co1)81Sn7B12 alloy starts as a growth with increasing nucleation rate. Then changes to growth with decreasing nucleation rate. After which nucleation rate decreases to zero. Rest of crystallization stage is governed by growth of pre-existing nuclei. In the first stage of crystallization alpha-Fe phase with bcc structure crystallizes from amorphous matrix. In the second stage of crystallization the remaining amorphous matrix crystalizes into tetragonal Fe2B phase and hexagonal FeSn phase. After the first stage of crystallization, 50 % to 55 % volume of studied alloys were crystalized. Addition of Cu decreases crystalline size of alpha-Fe crystallites by 60 % and de-creases concentration of Sn in alpha-Fe phase by 0.8 at. %. Addition of Co doesn't affect the size of alpha-Fe crystallites and decreases the concentration of Sn in alpha-Fe phase by 1.7 at. %.

In present work amorphous alloys Co 48 Fe 25 Si 4 B 19 Nb 4 -R (R = Nd, Sm, Tb, Yb) were obtained by planar flow casting in the form of ribbons with 3-5 mm wide and 35-45μm thickness. It was found that crystallization process goes into two stages and depends on the used rare-earth addition and its content in the alloy by differential thermal analysis method. Glass-forming ability criteria were calculated. It is shown that paramagnetic Curie temperature of alloys in liquid state can be used as their a-priori criterion of glass-forming ability. Keywords: amorphous alloys, crystallization, glass-forming ability, differential thermal analysis, x-ray diffraction, rare-earth metals.\

Cobalt and iron-based alloys with tendency to amorphization is a hot topic nowadays due to their unique magnetic and electrical properties. In the present work the differential thermal analysis (DTA) and density measurements of Co48Fe25Si4B19Nb4 alloy (base composition) with small additions of rare earth metals (Nd, Sm, Tb, Yb) are performed. The temperatures of phase transitions in the alloys are determined by DTA. It was found that small additions of rare earth metals (1 and 2 at %) increase solidus temperature and decrease liquidus of the base composition. Small thermal effects that were observed in the alloys with neodymium, terbium and ytterbium in the range 1080–1100°С, may indicate the decomposition of REM-B type compounds. In the alloys with samarium such effects were not found. That means that samarium does not form the Sm2B5 phase in the investigated alloys but goes into solution. Density was studied experimentally in a wide temperature range, including crystalline and liquid states, on an automated setup where the absolute variant of gamma-penetration method was realized. It is shown that temperature dependences of density in crystalline state are nonlinear and in liquid state are well described by linear functions. When melts are overheated above a certain temperature, density hysteresis (incoincidence of heating and cooling curves) appears; that may indicate structural transformations occurring in the melt. It is found that the rare-earth additions increase density of investigated alloys, however, this occurs non-linearly and depends on REM content. Basing on density experimental data, the coefficients of volume expansion and molar volumes are calculated.

The present work explores the applicability of a single spectroscopic technique, Laser-induced breakdown spectroscopy (LIBS), for the rapid quality assessment and quantification of individual layers of an amorphous bilayer ribbon (thickness similar to 35 mu m). This kind of materials (ribbon) offer a convolution of the two sets of unique properties of individual layer, in a single ribbon, in contrast to the layered systems prepared by thin film technologies, and are useful and applicable for sensing and actuating in different experimental conditions. The sample was prepared by rapid quenching using the modified double-nozzle technique. One side of the ribbon is a layer of iron (Fe) - silicon (Si) - boron (B) and other side of the ribbon consists of cobalt (Co) - silicon (Si) - boron (B). Owing to its versatility and advantages, LIBS has been used for assessing the elemental distribution on the surface of the investigated matrices and across the layer interface. After optimizing the experimental parameters, the LIBS measurements have been performed using a Q-switched Nd:YAG laser working at its second harmonic wavelength (532 nm) with the 30 mJ/pulse energy under ambient air and atmospheric pressure conditions. Following the LIBS spectral analysis, a chemometric approach, principal component analysis (PCA), has been used for the visualization of the spectra from the two layers and to observe dominant spectral lines responsible for the discrimination of both layers. The depth profile analysis of the layers has been carried out using LIBS and the number of pulses corresponding to the individual layers have been correlated with the depth of the ablation craters obtained using the 3D-optical profilometry in order to estimate the thickness of the individual layers and the ablation rates. Furthermore, the homogeneity of the sample has been examined by measuring the intensity of selected spectral lines corresponding to the composition of the sample. Calibration-free (CF) - LIBS analysis has been performed for the compositional quantification of both layers of the sample and found in a good agreement with the production ratio. This work paves the way towards the investigation and control of the properties of such intelligent materials.

Aluminum-containing amorphous and nano-crystalline alloys, especially compositions with transition and rare-earth metals, are being intensively investigated over the last years due to their high service properties. This paper studies thermophysical properties (density and electrical resistivity) of Al86Ni6Co2R6 (R = Nd, Gd, Yb) glass-forming compositions in a wide temperature range, including the liquid state. It is found that the behavior of crystalline alloys is typical for aluminum compositions, namely: the linear decrease in density and the growth in electrical resistivity with increasing temperature. It is shown that these compositions are characterized by a wide two-phase region, whereas a transition to the liquid state at the liquidus temperature is accompanied by an abnormal density growth and electrical resistivity reduction. For the first time, it is found that the melt overheating up to 1350 K leads to the density hysteresis, which probably indicates to the fracture of large-scale inhomogeneity in melts.

Electrical resistivity and magnetic susceptibility of Co48Fe25Si4B19Nb4 + REM (REM = Nd, Sm, Tb, Yb) alloys in crystalline and liquid states are studied. Experimental data were used to calculate the electronic characteristics (effective magnetic moment, density of states at the Fermi level, and paramagnetic Curie temperature) of melts. It is shown that all the rare-earth metals considered must increase the glass-forming ability of alloys, but neodymium and samarium can have the maximum effect.

Density and electrical resistivity of Al-Ni-Co-Sm(Tb) glass-forming alloys were studied in wide temperature range include liquid state. It was found the sharp increase of density and decrease of resistivity at liquidus temperature. It was discovered that heating of the melts above a certain temperature leads to the appearance of a hysteresis of properties. Thermal expansion coefficient and temperature coefficient of resistivity were calculated from experimental data.

Electrical resistivity and magnetic susceptibility of Co48Fe25Si4B19Nb4 + R (R = Nd, Sm, Tb, Yb) alloys in crystalline and liquid states were studied in present work. Electronic characteristics (effective magnetic moment, density of states at the Fermi level and paramagnetic Curie temperature) were calculated from experimental data. It is shown that all rare earth metals that were used should increase the glass-forming ability of alloys, but neodymium and samarium can have the greatest effect.