Alloy Ribbons Research Articles

Fe基合金薄带应力感生磁各向异性非线性关系研究

Fe基合金薄带应力感生磁各向异性非线性关系研究

Highly sensitive glucose sensor based on hierarchical CuO

The fabrication of high performance CuO based glucose sensors remains a great challenge due to the “trade-off effect” between sensitivity and linear range. In this study, a hierarchical CuO nanostructure with a great number of firecracker-shaped nanorods along the ligament and three-dimensional interconnected nanoporous is obtained by dealloying and post oxidation process of Al-33.3 wt% Cu eutectic alloy ribbons. Because of the precise structural design, not only the number of active sites for glucose electro-oxidation is significantly increased but also the glucose diffusion under high concentration is greatly accelerated, leading to a high sensitivity of 1.18 mA cm−2 mM−1 and a wider linear range up to 5.53 mM for glucose detection. This work provides a potential approach to design hierarchical nanostructure for other metal oxides with desirable properties for electrocatalytic applications.

Investigation of thermal-structural characteristics at two-way shape memory effect of rapid quenched laminated amorphous-crystalline ribbons of Ti50Ni25Cu25 alloy

The work is devoted to the study of processes of structural changes leading to the realization of the two-way shape memory effect (TWSME) in the rapid quenched amorphous-crystalline alloy Ti50Ni25Cu25. The object of the study was a rapid quenched laminated amorphous-crystalline Ti50Ni25Cu25 alloy ribbon with a thickness of about 39 um and with a thickness of surface crystal layer about 10 μm was present on the non-contact side relative to the quenching wheel. In the ribbon under study, without any additional heat treatments the TWSME with bending deformation from a rectilinear shape during heating and cooling in the range of martensitic transformation is manifested. The samples were characterized by means: scanning and transmission electron microscopy; X-ray diffraction analysis; differential scanning calorimetry; measuring the characteristics of the crystalline layer during the implementation of TWSME and the temperature dependence of the form change. It was shown that the formation of a laminated amorphous-crystalline composite occurs due to the martensitic transformation of B2∼B19 in the crystal layer and the accompanying TWSME as a result of which the crystal layer is reduced.

Formation of structure of TiNiCu alloys with high copper content upon producing by planar flow casting

The rapidly quenched alloys of the quasibinary intermetallic TiNi-TiCu system with a high copper content (more than 25 at.%) are of great interest as shape memory materials due to the possibility of a significant decrease in the temperature and deformation hysteresis in comparison with the binary TiNi alloy. To obtain alloys with a copper content of 25 to 40 at.%, the planar flow casting technique was used. The alloys were fabricated at a melt cooling rate of about 106 K/s in the form of ribbons 30-50 μm thick and wide in the range from 7 to 20 mm. The study of the structure of the alloys was carried out using X-ray diffraction analysis, scanning and transmission electron microscopy. It was shown that from the ribbon side, contacting the quenching wheel, all alloys are amorphous, while on the non-contact side of the ribbons of alloys with 25 and 30 at.% Cu, a thin surface crystalline layer with a B2 structure is observed. Using energy dispersive X-ray spectroscopy, it was found that the content of the alloy components in the amorphous and crystalline phases coincides.

Структура и механические свойства композитных аморфно-кристаллических материалов на основе алюминия, синтезированных кручением под высоким давлением.

The results of the structural studies and hardness measurements of bi-and three-layer samples obtained by high pressure torsion of melt-spun ribbons of Al-based alloys with amorphous and crystalline structures have been presented. It has been established that straining of amorphous ribbons results in formation of nanocomposite structure while that refinement of crystalline structure and increase of microstrains takes place in crystalline ribbon. It has been found that the hardness of the consolidated samples increases with the increase of the deformation level up to 4,7 GPa.

Novel photovoltaic ribbon technology: Interfacial behavior of In–50Sn alloy ribbon without metal matrix under electrothermal effects and chlorine corrosion

In this study, an In–50Sn alloy ribbon without a metal matrix was developed as a substitute for traditional dipped-photovoltaic (PV) ribbons. In–50Sn alloy ribbon reflowed directly onto an Ag electrode on a Si solar cell, and the formed Ag–In intermetallic compound (IMC) was used to connect the Si substrate and PV ribbon. Only one IMC layer was formed in the In-50Sn PV module structure. After bias aging or thermal aging tests, electrothermal effects influenced the interfacial structures, but the IMC and series resistance of the module structure did not increase substantially. NaCl immersion was conducted to evaluate the corrosion resistance of the In–50Sn PV module. Chloride ions preferentially corrode the interface between Ag paste and a Si solar substrate, causing poor bond reliability. Modules with a reduced amount of Ag paste were used on the Si solar substrate and achieved bond strength that met the industry standard. The PV ribbon without the metal matrix limited IMC growth and thus resulted in a module with a long operating lifetime.

Effects of Nb and Mo additions on thermal behavior, microstructure and magnetic property of FeCoZrBGe alloy* *Project supported by the National Natural Science Foundation of China (Grant No. 51301075) and supported by Sinoma Institute of Materials Research (Guang Zhou) Co., Ltd.

Both Nb and Mo additions play a vital role in FeCo-based alloys and it is crucial to understand their roles and contents on thermal behavior, microstructural feature and magnetic property of alloys. Nanocrystalline alloy ribbons Fe40Co40Zr9 – y M y B10Ge1 (y = 0–4; M = Nb, Mo) were prepared by crystallizing the as-quenched amorphous alloys. The effects of Nb and Mo additions on structures and properties of the Fe40Co40Zr9B10Ge1 alloy are investigated systemically and compared. With increasing Nb or Mo content, the primary crystallization temperature, grain size of α-Fe(Co) phase and coercivity H c all decrease. Moreover, the effect of Mo addition on thermal behavior, microstructure and magnetic properties of the FeCoZrBGe alloy is greater compared to Nb addition. The gap between primary and secondary crystallization peaks of Mo-containing alloys is wider than that of Nb-containing alloys. Both grain size and H c of Mo-containing alloys are smaller than those of Nb-containing alloys. For Fe40Co40Zr9B10Ge1 alloy, high Mo addition proportion is better compared to high Nb addition proportion.

Heat treatment effect on the evolution of magnetic properties of martensite in magnetic shape memory Ni48Mn39.5Sn9.5Al3 Heusler alloy ribbons

The magnetic ground state of martensite in Ni48Mn39.5Sn9.5Al3 ribbons shows considerable complexity and a two stage behavior. Initially, below the blocking temperature it evolves from a superparamagnetic state into a frozen state with a strong ferromagnetic component and it manifests some spin glass like characteristics. The ferromagnetic component is sensitive to thermal treatment, what stems from its susceptibility to variation in the retained ferromagnetic austenite fraction, change in the degree of order as well as the density of ferromagnetic/antiferromagnetic domain interfaces. At temperatures below 80 K, a divergence from linear correspondence to the Almeida-Thouless law signifies that the system enters into a magnetically harder and inhomogeneous state distinguished by exchange bias.

Martensitic Transition, Magnetic, Microstructural and Exchange Bias Properties of Melt Spun Ribbons of Mn-Ni-Sn Shape Memory Heusler Alloy

In the present report, we have studied the structural, microstructural, magnetic, exchange bias (EB) properties and magnetoresistance (MR) in Mn rich (Mn at. ∼50%) Mn50Ni50−xSnx (x = 10) shape memory Heusler alloy ribbons, prepared using the melt spinning method. These ribbons were found to exhibit a first order structural (i.e., martensitic) transition at around 205 K from the high temperature austenite to the low temperature martensite phase. The martensitic transition occurs at comparatively lower temperatures in these ribbons than in the same bulk alloy. Curie temperature of the austenite phase (TCA) is found to be larger i.e., around room temperature than that of bulk alloy. A significant EB field (HEB) of around 960 Oe has been observed at 2 K for these ribbons, which is found to be comparable to that reported for other Heusler systems. The presence of the EB effect in these ribbons is attributed to the coexistence of FM/AFM exchange interactions in the martensite phase. They are also found to show a maximum negative MR of around 12% near the martensitic transition, for 50 kOe field change. Investigation of DC magnetization, AC susceptibility measurements and the observation of training effect (i.e., characteristic feature of EB) strongly corroborates with the coexistence of FM/AFM exchange interactions in the martensite phase of these ribbons, which results in the large EB. The effects of temperature and magnetic field on the EB properties and MR have also been studied here.

Thermal behavior, microstructure and magnetic properties of (FexNiyCoz)80B10Si2Cu1Zr7 alloys

Amorphous (FexNiyCoz)80B10Si2Cu1Zr7 (x + y + z = 1) alloys were prepared by melt spinning. By investigating the glass-forming ability, thermal behavior, crystallization and magnetic properties of alloy ribbons, detailed and integral pseudoternary diagrams of (FexNiyCoz)80B10Si2Cu1Zr7 alloys were constructed, which can make one clearly understand the effects of ferromagnetic elements (Fe, Co, Ni) on microstructure and physical properties. Results show that, all as-spun alloys show a fully amorphous structure and the coercivity (Hc) can be tuned to a lower value than 45 A/m. After being annealed, alloys with Ni content lower than 64 at.% (y < 0.8) show a refined structure of nanocrystals with an average size about 3–14 nm uniformly dispersed in the residual amorphous matrix, and the Fe-rich and Ni-rich alloys exhibit Hc < 155 A/m comparing with the Co-rich alloys (155–416 A/m). No matter as-spun or annealed alloys, (Co + Ni):Fe = 3:7 is the optimal composition to obtain the maximum saturation magnetization (Ms) when y is a certain value in the range of 0–0.2. In addition, alloys in the whole range of composition were classified according to comprehensive magnetic properties of Ms and Hc. The Fe-rich alloys exhibit typical soft magnetic characteristics of simultaneously high Ms and low Hc, as well as high thermal stability of fully amorphous structure or uniform “primary crystalline phase + residual amorphous” structure. All results give a better insight for amorphous and nanocrystalline (FexNiyCoz)80B10Si2Cu1Zr7 alloys to further analyze more efficient magnetic alloys in inductors, transformers, magnetic recording and other magnetic functional materials.

Structure, Magnetic Properties and Magnetic Impedance of Fast Quenched Ribbons of Alloys Based on FINEMET in the Initial State and After Heat Treatment

Abstract–The effect of heat treatment (HT) on the structural features, magnetic properties, and magnetic impedance of rapidly quenched Fe73.5Si13.5B9Nb3Cu1 ribbons and doped ribbons, in which 10 wt % iron is replaced by either cobalt, nickel, or manganese, is studied in this paper. Cobalt ribbons as a result of HT at a constant temperature showed a significant increase in the value of maximum magnetic induction. The magnetic and magnetic-impedance properties, studied in a wide range of alternating current frequencies from 1 to 400 MHz, showed a significant change in the features of effective magnetic anisotropy and high-frequency responses after HT. A comparative analysis of the results obtained for samples of various compositions can be useful both for understanding the features of the formation of effective magnetic anisotropy in nanocrystalline alloys and from the point of view of practical applications in the search for optimal physicochemical parameters of materials for sensors of low magnetic fields.

Effects of annealing temperature and heating rate on microstructure, magnetic, and mechanical properties of high-Bs Fe81.7−xSi4B13NbxCu1.3 nanocrystalline alloys

The effects of annealing temperature and heating rate on the microstructure, magnetic, and mechanical properties of melt-spun Fe81.7−xSi4B13Cu1.3Nbx (x = 0–4) alloy ribbons have been investigated. With increasing the annealing temperature, a ductile–brittle transition occurs during amorphous structure relaxation, the brittleness becomes severe with more α-Fe precipitation, and the hardness rises continuously. After annealing at respective optimum temperatures under the heating rate of 20 K/min, as the Nb content increases from 0 to 4 at.%, average grain size (Dα-Fe) and volume fraction (Vα-Fe) of the α-Fe in the nanocrystalline alloys decrease gradually from 53.3 nm and 52% to 8.7 nm and 42%, respectively; the strain at fracture (ef) representing ductile level increases from 1.33 to 1.72%; and the coercivity (Hc), saturation magnetic flux densities (Bs), and Vickers hardness (Hv) all decrease gradually. As the heating rate rises from 10 to 400 K/min, the Dα-Fe of the Fe81.7Si4B13Cu1.3 alloy decreases from 45.7 to 28.4 nm without considerable variation of the Vα-Fe; the Hc lowers from 235 to 25 A/m, the ef increases from 1.10 to 1.66%, and the Bs and Hv change slightly. Enriching of Nb weakens the dependence of nanostructure, magnetic softness, and annealing embrittlement on the heating rate. A correlation of ef ∝ Dα-Fen is found for the nanocrystalline alloys, where the n rises from − 1 to − 1/2 with enriching of Nb from 0 to 4 at.%. The mechanisms by which nanostructure affects magnetic and mechanical properties have been discussed.

Significantly improved particle strengthening of Al–Sc alloy by high Sc composition design and rapid solidification

Sc alloying is usually carried out by adding a small amount of Sc in typical aluminum alloys to improve the mechanical properties, however, the effect of high-Sc content on the microstructure and properties of aluminum alloys is rarely concerned. To further understand the role of Sc alloying, several Al–Sc binary alloys with high-Sc content are designed and the relationship between the Sc content and mechanical properties were investigated. It is found that the mechanical properties of Al–Sc binary alloy is determined by both the Sc content and the cooling rate. The addition amount of Sc shows relatively small effect on the mechanical properties at low cooling rate, but higher at high cooling rate, because cooling rate turns the size and distribution of Al3Sc particles. Through the high Sc content alloy design and melt spinning rapid cooling technology, the densely distributed Al3Sc precipitate of about 250 nm can be located inside the α-Al grains, resulting in the intracsystalline reinforcement. The combination of high tensile strength (344 MPa) and good plasticity (5.7%) were achieved at a grain size of ~500 nm in the hypereutectic Al–Sc binary alloys ribbons. The significant strengthening could be attributed to multiple strengthening mechanisms including (1) Orowan strengthening; (2) coefficient of thermal expansion (CTE) mismatch strengthening; (3) the Hall-Petch effect caused by grain refinement; (4) solid solution strengthening. When the cooling rate is increased, the effects of thermal mismatch strengthening and Orowan mechanism are more prominent, significantly improving the strength of the Al–Sc alloy. The present experimental results provide an insight into the understanding of microstructural evolution of nanoparticles, and extend the effort for the development of hypereutectic Al–Sc alloys as a member of high-strength structural materials.

Optimization of crystallization behavior and soft magnetic properties of the Si-free Fe-B-P-C-Cu nanocrystalline alloys by Cu content tuning

The effect of Cu content on amorphous forming ability (AFA), crystallization behavior and soft magnetic properties of the new Si-free Fe84-xB9P3C4Cux (x = 0.7, 0.9, 1.1, 1.3 and 1.5) alloys were systematically investigated. The phase structure identified by XRD reveals that the alloys for Cu content less than 1.3 at. % have good AFA. The dependence of activation energies of nucleation and growth on Cu content shows that the growth of α-Fe grains is more difficult than the nucleation for the alloy ribbons with Cu ≤ 1.1 at. %, which is beneficial to obtain finer nanocrystalline α-Fe grains during crystallization annealing, while for those with Cu > 1.1 at. %, the growth of α-Fe grains is easier than the nucleation. The relationship between coercivity (Hc) and the annealing temperature (Ta) indicates that appropriate Cu content is beneficial to improve the stability of soft magnetic properties, especially, when annealed near the temperature of the first crystallization peak. The nanocrystalline Fe82.9B9P3C4Cu1.1 alloy exhibits a high saturation magnetic flux density of 1.84 T ~ 1.85 T and a low Hc of 13.0 A/m ~ 8.9 A/m annealed in the range of 703 K ~ 763 K.

Structural and Hydrogen Storage Properties of Mg60-Ni40 and Mg80-Ni20 Alloys Prepared by Planar Flow Casting

This study was carried out to better understand the chemical composition, microstructure, and hydrogen properties of Mg binary alloys. In this study, Mg60-Ni40 and Mg80-Ni20 (wt.%) alloy ribbons with different microstructures have been produced by the melt spinning method. The structural, hydriding, and dehydriding properties of the alloys were evaluated. The phase constitutions and microstructures were characterized by XRD and SEM studies. Microstructural grain sizes measured for Mg60-Ni40 alloy ribbons were in the range of 1-5 µm, and the alloy contained finely dispersed Mg and Mg2Ni phases. In the case of Mg80-Ni20 alloy ribbons, the microstructural grain sizes were measured as less than 1 µm. The hydrogen absorption and desorption capacities and kinetics of these two alloys were found to be highly dependent on microstructure and phase properties. Also, the amount of Ni content affected both the hydrogen storage capacities and kinetics for both of the Mg-Ni binary alloys. The increasing amount of Ni resulted in reduced hydrogen absorption capacity. The Mg60-Ni40 and Mg80-Ni20 alloy ribbons demonstrated superior hydrogenation absorption capacity at 350 °C and reversibly absorbed about 4.62 and 5.51 (wt.%) mass hydrogen, respectively.

Rapid solidification of ternary Nb‐Y‐Ni immiscible alloys

AbstractThe rapid solidification experiments have been carried out for the Nb(45‐x)YxNi55 (x = 9, 19, and 27) alloys. The microstructure characterization shows the occurrence of the liquid‐liquid phase separation into the Niobium‐rich and Yttrium‐rich liquids. The Niobium‐rich spherical particles were embedded in the glassy Yttrium‐rich matrix for the alloy Nb36Y9Ni55, while glassy Yttrium‐rich ones were located in the glassy Niobium‐rich matrix for the alloy Nb18Y27Ni55. A structure of hierarchical separation was detected in the as‐quenched alloy Nb26Y19Ni55. The size distribution of the spherical particles in the as‐quenched Nb(45‐x)YxNi55 (x = 9 and 27) alloys ranges from several nanometers to sub micrometer and is close to the Gaussian distribution. The average diameters of the Niobium‐rich particles in the as‐quenched Nb36Y9Ni55 alloy and the Yttrium‐rich particles in the Nb18Y27Ni55 alloy are 0.23 μm and 0.15 μm, respectively. A dual‐glass structure in the as‐quenched Nb18Y27Ni55 alloy ribbon was determined by X‐ray diffraction and transmission electron microscopy.

Improved alkaline hydrogen evolution performance of a Fe78Si9B13 metallic glass electrocatalyst by ultrasonic vibrations

The electrocatalytic performance of a Fe78Si9B13 amorphous alloy toward alkaline hydrogen evolution reaction (HER) is enhanced by ultrasonic vibration (UV). The UV treatments slightly increase the crystallization enthalpy of the Fe78Si9B13 amorphous alloy from 141.54 J/g to 145.32 J/g, meanwhile a large number of micro-cracks, -holes and -chips are generated on the surface of the amorphous alloy. The overpotentials of the amorphous alloy treated with ultrasonic energy of 5000 J is only 173 mV at 10 mA cm−2 in 1.0 M KOH, which is reduced from 386 mV for the amorphous ribbon alloy at the same conditions. Moreover, the UV treated amorphous alloys also show better HER cycling performance comparing with those of the amorphous alloy without UV treatment. After 1000 CVs, it only needs 127 mV to reach the current density of 10 mA cm−2 for the materials treated with 5000 J. After 1000 CVs cycling reaction, the UV treated amorphous alloy shows much enlarged specific area compared with that of the untreated amorphous alloy, which should be the reason for the improved cycling HER performance.

Impact of annealing on the martensitic transformation and magnetocaloric properties in all-3d-metal Mn50Ni32Co8Ti10 alloy ribbons

The effects of annealing at different temperatures (1053, 1103, 1153 K) on the martensitic transformation (MT) and magnetocaloric effect have been investigated in all-3d-metal Mn50Ni32Co8Ti10 alloy ribbons. In melt-spun ribbons, a coexistence of predominant 5-layer modulated martensite (5 M, monoclinic, space group P2/m) and a small amount of B2-type austenite with a cubic structure is revealed at room temperature (RT), demonstrating that the forward MT temperature (TtFC ) lies just above the RT. After annealing, the coexistence of three different phases, the non-modulated L10 martensite (NM, tetragonal, space group P4/mmm), 5 M martensite, and B2 austenite, and the enhanced intensity of both B2 (400) and L10 (220) characteristic peaks exhibited in X-ray diffraction patterns are suggestive of the fact that TtFC is reducing. The (TtFC )-reduction induced by heat treatment is also confirmed by thermomagnetic measurements. TODC:TtZFCinthissentenceshouldbealsodeletedThe magnetic entropy change maximum also decreases after annealing because the MT slows down. However, it is worth noting that after annealing the effective refrigeration capacity increases more than twice of the melt-spun sample. The origin of (TtFC )-reduction induced by annealing is discussed.

Heterostructured crystallization mechanism and its effect on enlarging the processing window of Fe-based nanocrystalline alloys

The harsh melt-spinning and annealing processes of high saturation magnetization nanocrystalline soft-magnetic alloys are the biggest obstacles for their industrialization. Here, we proposed a novel strategy to enlarge the processing window by annealing the partially crystallized precursor ribbons via a heterostructured crystallization process. The heterostructured evolution of Fe84.75Si2B9P3C0.5Cu0.75 (at.%) alloy ribbons with different spinning rate were studied in detail, to demonstrate the gradient nucleation and grain refinement mechanisms. The nanocrystalline alloys made with industrially acceptable spinning rate of 25−30 m/s and normal annealing process exhibit excellent magnetic properties and fine nanostructure. The small quenched-in crystals/clusters in the free surface of the low spinning rate ribbons will not grow to coarse grains, because of the competitive grain growth and shielding effect of metalloid elements rich interlayer with a high stability. Avoiding the precipitation of quenched-in coarse grains in precursor ribbons is thus a new criterion for the composition and process design, which is more convenient than the former one with respect to the homogenous crystallization mechanism, and enable us to produce high performance nanocrystalline soft-magnetic alloys. This strategy is also suitable for improving the compositional adjustability, impurity tolerance, and enlarging the window of melt temperature, which is an important reference for the future development of composition and process.

Effect of Annealing Process on Magnetic Properties, Structures and Coercivity Mechanism in Nanocrystalline Pr8Dy1Fe60Co7M3Ni3B14Zr1Ti3 Alloy Ribbons

Effect of Annealing Process on Magnetic Properties, Structures and Coercivity Mechanism in Nanocrystalline Pr₈Dy₁Fe₆₀Co₇M₃Ni₃B₁₄Zr₁Ti₃ Alloy Ribbons