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This paper delineates a single-step production method of nanostructured diiron boride (Fe2B) and its structural, magnetic and magnetothermal properties. Structurally Fe2B resembles the tetragonal copper aluminide, CuAl2. The samples of nanostructured Fe2B were synthesized by milling Fe and B powders without any pre-treatment. Single phase Fe2B nanoparticles were successfully produced with the crystallite sizes of 68 and 46 nm after milling the powders for 10 h and 20 h, respectively. The saturation magnetization of the samples was found to decrease with increased milling time indicating that the surface spin disorder plays a crucial role in the magnetic properties. The highest saturation magnetization (Ms) of 141 emu/g with low coercivity (Hc) of 48 Oe was obtained for the 10 h milled sample of Fe2B, whereas the 20 h milled sample exhibited Ms and Hc as 129 emu/g and 149 Oe. This paper also presents a detailed information on the total and atom projected densities of state functions as well as the magnetic moment contribution of the individual atoms of Fe and B in Fe2B explaining the strong room temperature ferromagnetic properties contributed by the large number of unpaired 3 d electrons in Fe. The magnetothermal properties of the as-made Fe2B nanocrystals of high magnetic moment were investigated by measuring the rise in temperature as a function of time in the presence of AC magnetic fields. The magnetic Fe2B nanocrystals show significant thermal response with the high specific absorption rate of 172 W/g, demonstrating the advantages of using Fe2B nanocrystals for the application in magnetic fluid therapy for hyperthermia.

Bu çalışmada, nanoyapılı Fe (Al,Cu) katı çözeltisi, elementel tozların mekanik alaşımlama (MA) işlemi ile sentezlenmiştir. Toz karışımlar, 50 saatlik öğütme süresince çeşitli zaman aralıklarında gezegensel bilyeli değirmende öğütülmüştür. Numunelerin yapısal ve mekanik özellikleri X-ışını difraksiyonu (XRD), taramalı elektron mikroskobu/ enerji dağılımlı X-ışını spektroskopisi (SEM/ EDX) ve Vickers mikrosertlik (HV) testi ile incelenmiştir. 10 saatlik öğütme işleminden sonra bütün Al ve Cu atomları ymk-Fe (Al,Cu) katı çözeltisini oluşturmak üzere Fe kafesi içerinde çözünmüştür. Toz alaşımların parçacık morfolojisi öğütme süreleri boyunca soğuk kaynaklanma, kırılma ve kararlı durum aşamalarını göstermiştir. 50 saatlik öğütme işleminden sonra parçacık boyutu ve kristalit boyutu, sırasıyla ~ 500 nm ve ~ 6 nm’ ye düşmüştür. Bununla birlikte, mikrosertlik değerleri artan öğütme süresiyle birlikte artmıştır.

Nanostructured (FeCoNi)70Ti10B20 (at%) alloy was synthesized by mechanical alloying from elemental powder mixture of Fe, Co, Ni, Ti and B using ball milling. The effect of ball milling time on the evolution of structure and morphology was investigated by X-ray diffraction, scanning and transmission electron microscopy and differential thermal analysis. It was observed that the formation of solid solution of (FeCoNi)70Ti10B20 started from the very onset of the milling process. Crystallite size and lattice strains seemed to be leveled off after 20 h of milling with no further major changes. The milling process for longer periods introduced severe plastic deformations causing formation of amorphous phase of (FeCoNi)70Ti10B20. The amorphous alloy composition was confirmed by energy dispersive X-ray spectroscopy analysis that showed an excellent homogeneity of the alloying elements. The phase stability of the mechanically alloyed amorphous sample was further verified by employing high-temperature and high-pressure studies. The alloy samples heat-treated at 700 °C revealed crystallization of the amorphous phase. However, synchrotron-based high-pressure ambient temperature X-ray diffraction studies confirmed that the amorphous phase of the alloy remained stable up to the pressure of 30 GPa. The 50 h milled sample after being annealed at 350 °C showed improvement in the soft magnetic properties of the alloy, which was due to the probable elimination of the residual stress in the amorphous phase of the alloy powders.

Buçalışmada nanokristal Co70Si15B15 (at.%) tozalaşımları, mekanik alaşımlama (MA) tekniği ile farklı öğütme sürelerindeüretilmiştir. Öğütme süresince alaşımların yapısal değişimleri, parçacıkmorfolojisi, termal kararlılıkları ve manyetik özellikleri incelenmiştir. X-ışınıdifraksiyonu (XRD) sonuçları, elementel tozların birbirleri ile olan reaksiyonusonucu nanokristal Co(Si,B) katı çözelti fazını oluşturduğunu göstermiştir.Taramalı elektron mikroskobu (SEM) analizlerinden morfolojinin alaşımlamaboyunca değiştiği ve parçacık boyutunun öğütmenin ilk safhalarında arttığı,daha sonra küçüldüğü anlaşılmıştır. Alaşımların yapısal durumuna bağlı olarakgörülen ekzotermik reaksiyonun aktivasyon enerjisi 128 ± 3 kJ/mol olarakhesaplanmıştır. Manyetik sonuçlar, artan öğütme süresiyle hem doyummanyetizasyonunun (Ms) hem de koersivitenin (Hc)azaldığını göstermiştir., Inthis research, nanocrystalline Co70Si15B15(at.%) powder alloys were prepared by mechanical alloying (MA) technique atvarious milling times. Their structural changes, particles morphology, thermalstability and magnetic properties through the milling process wereinvestigated. The X-ray diffraction (XRD) results showed that reaction of theelemental powders mixture resulted in the formation of the nanocrystallineCo(Si,B) solid solution phase. According to the scanning electron microscopy(SEM) analysis, particle morphology was changed during alloying and theparticle size increased initially, then decreased. Depending on the structuralstate of the alloys, the apparent activation energy of the exothermic reactionwas calculated as 128 ± 3 kJ/mol. Magnetic results indicated that bothsaturation magnetization (Ms) and coercivity (Hc) weredecreased with increasing milling time.

Bu çalışmadananoyapılı Al85Co7Y8 (at.%) alaşımı, mekanikalaşımlama (MA) tekniği kullanılarak elemental tozların katı hal reaksiyonuylasentezlenmiştir. Toz alaşımlar, argon gazı altında sertleştirilmiş paslanmazçelik hazne ve bilyeler kullanılarak yüksek-enerjili bilyeli değirmeniçerisinde 300 saatlik öğütme işlemine tabi tutulmuştur. Öğütme işlemi süresincenumunelerdeki yapısal ve morfolojik değişimler X-ışını difraksiyonu (XRD) vetaramalı elektron mikroskobu (SEM) ile termal kararlılıkları ise diferansiyeltermal analiz (DTA) ile incelenmiştir. MA işlemi sonucunda aşırı doymuş fcc-Alkatı çözelti fazı içeren alaşımlar üretilmiştir. Al85Co7Y8alaşımının 300 saatlik öğütme işlemi sonrasındaki kristalit boyutu yaklaşık 16nm olarak bulunmuştur., Inthis study, the nanostructured Al85Co7Y8(at.%) alloy was synthesized by a solid state reaction from the constituentelemental powder mixture via mechanical alloying (MA). The powder mixture wasball milled for times up to 300 h in a planetary high energy mill usinghardened steel media under argon atmosphere. Structural and morphologicalchanges during the milling process were characterized by a combination of X-raydiffraction (XRD) and scanning electron microscopy (SEM) techniques. Thermalstability of the milled powders was investigated using differential thermalanalysis (DTA). The results showed that supersaturated α-Al solid solution wasformed in the whole content of the milled material. The mechanically alloyed Al85Co7Y8powder for 300 h of milling indicated the formation of fine nanoparticles witha size of about 16 nm.

In this study, nanocrystalline Ti and TiO2 powders were synthesized by wet milling of Ti powder within water and reactive milling of Ti powder under oxygen atmosphere, respectively. The wet milling processes were performed at 300 rpm milling speed for different milling durations (6, 12, 24, and 48 h). Subsequent heat-treatments of the as-milled powders were performed at 200-800 °C for 1 h in an air atmosphere. Structural characteristics of the as-milled and the heat-treated powders were investigated by X-ray diffraction (XRD). The crystallite size, lattice strain and lattice parameters of the powders were also calculated. It has been realized that during the wet milling process, elemental Ti powder undergoes an hcp to fcc polymorphic transformation, which is related to grain refinement and plastic strain. In addition, TiO 2 powders are produced after heat-treatments at 600 and 800 °C. Reactive milling of the elemental Ti powder in pressurized oxygen atmosphere leads to nanocrystalline TiO2 powders with an average crystallite size of about 10 nm after 48 h milling time. The subsequent heat-treatments of the as-milled TiO2 powders results in the increase of the crystallite size up to 70-150 nm. In order to understand the thermal behavior of the as-milled powders, thermal analysis (DTA) and thermogravimetric analysis (TGA) were employed. The activation energy of the nanocrystalline TiO2 powders was determined by the Kissinger method is 128±3 kJ/mol. © 2014 Elsevier Ltd and Techna Group S.r.l. All rights reserved., 0901-602006, We would like to thank Hacettepe University , Scientific Research and Development Office, through the Grant (no. 0901-602006 ) and TUBITAK-BIDEP postdoctoral research fellowship.

The alloys with different compositions in the Al-rich corner of the Al-Co-Y ternary system were prepared by conventional casting and further processed by melt-spinning technique. The microstructure and the thermal behavior of the alloys were analyzed by means of X-ray diffraction (XRD), scanning electron microscopy (SEM), differential scanning calorimetry (DSC), and differential thermal analysis (DTA). It was found that only rapidly solidified Al85Co7Y8alloy exhibited the best glass forming ability (GFA) and a fully amorphous structure. Besides, Al85Co13Y2and Al85Co2Y13alloy ribbons were fully crystalline, whereas Al85Co10Y5and Al85Co5Y10alloy ribbons consisted of some crystalline phases within an amorphous matrix. The SEM results showed the same trend that the crystalline phase fraction decreases with the approaching into best glass former. From DSC results, only Al85Co7Y8amorphous alloy exhibited a glass transition temperature (Tg) at 569 K, and its supercooled liquid region (ΔTx=Tx−Tg) was found to be 17 K. Moreover, other calculated GFA parameters for this alloy system were also discussed.

In this study, the microstructures and mechanical properties of conventionally solidified Al 63 Cu 25 Fe 12 alloy after different heat-treatments were investigated. The microstructures of the as-cast and subsequently heat-treated samples were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and differential thermal analysis (DTA). The XRD results showed the presence of quasicrystalline icosahedral phase (i-phase) together with crystalline phases corresponding to β-AlFe(Cu) solid solution phase (β-phase) and τ-AlCu(Fe) solid solution phase (τ-phase). The SEM investigations clearly showed the formation of i-phase with pentagonal dodecahedra structure. However, the i-phase together with β-phase was also observed in the heat-treated samples and the peak intensity of the β-phase decreased with increasing heat-treatment temperature. From the DTA curves, the melting point of i-phase was determined as 890 °C for this alloy composition. Mechanical properties of the as-cast and subsequently heat-treated samples were measured by a Vickers indenter. Results showed that the microhardness ( HV ) and the elastic modulus ( E ) of the as-cast sample were around 598 kg fmm −2 (5.86 GPa) and 104 GPa, respectively. In addition, the characteristic of material plasticity ( δ H ) value was calculated to be 0.54.

A new ONNO-type azomethine ligand, 2,2′-(ethane-1,2-diylidenedinitrilo)dibenzoic acid, (YLH2) (1) has been prepared by the condensation of 2-aminobenzoic acid and glyoxal. The coordination compounds [Ni(YL)] (2), [Co(YL)] (3), [Cu(YL)(H2O)] (4), [Zn(YL)] (5), and [Cd(YL)] (6) of the YLH2 ligand with five transition metal ions, Ni(II) Co(II), Cu(II), Zn(II), and Cd(II) have been prepared. The structures of these new azomethine compounds are proposed on the basis of the elemental analyses, proton nuclear magnetic resonance, infrared, ultraviolet–visible spectroscopy, and X-ray powder diffraction patterns. Elemental analyses indicate a ligand metal ratio of 1:1 in the coordination compounds. X-ray powder diffraction parameters for [Cu(YL)(H2O)] and [Cd(YL)] compounds correspond to orthorhombic and monoclinic structures, respectively. The ligand acts as a tetradentate ligand bending through oxygen atoms of the hydroxyl groups of benzoic acid and nitrogen atoms of the azomethine groups. In addition, the ligand and its metal complexes have been studied for their possible genotoxic potential. © 2011 Wiley Periodicals, Inc. Heteroatom Chem 22:119–130, 2011; View this article online at wileyonlinelibrary.com. DOI 10.1002/hc.20665

In this work, the multicomponent Co60Fe5Ni5Ti25B5 (at.%) alloy powders were synthesized from commercially available pure elemental powders by using a mechanical alloying (MA) process under argon gas atmosphere. The changes in structural, morphological, thermal and magnetic properties of the processed powders during MA were examined by X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM/EDX), differential thermal analysis (DTA) and vibrating sample magnetometer (VSM). The results showed that the amorphization occurred after 3.5 h of milling, and the amorphous phase was stable up to 580 degrees C, where crystallization occurred. The SEM observations indicated that different morphologies were obtained during the MA stages. In addition, the EDX mapping confirmed the uniform distribution of elemental content. Magnetic results indicated that all the samples exhibited soft-ferromagnetic behavior. The evolution of the saturation magnetization (Ms), the coercivity (Hc) and the squareness ratio (Ms/Mr) during milling process were discussed with respect to microstructural changes. The influence of the annealing on magnetic hysteresis was also studied. The Ms, Hc and Ms/Mr values of about 53.4 emu/g, 7.6 Oe and 0.01, respectively was obtained after 7 h of milling. (C) 2015 Elsevier B.V. All rights reserved.

A new, substituted 2-[(E)-{[4-(benzyloxy)phenyl]imino} methyl]-4-[(E)-(4-nitrophenyl)diazenyl]phenol azo-azomethine ligand (mbH) was synthesized from 2-hydroxy-5-[(4-nitrophenyl)diazenyl]benzaldehyde and 4-benzyloxyanilinehydrochloride in ethyl alcohol solution. These mononuclear Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) complexes of the ligand were prepared and their structures were proposed by elemental analysis, and infrared and ultraviolet-visible spectroscopy; the proton NMR spectrum of the mbH ligand was also recorded. The azo-azomethine ligand, mbH, behaves as a bidentate ligand coordinating through the nitrogen atom of the azomethine (--CH=N--) and the oxygen atom of the phenolic group. Elemental analyses indicated that the metal:ligand ratio was 1:2 in the metal chelates. Powder X-ray diffraction parameters suggested a monoclinic system for the mbH ligand and its Ni(II), Cu(II), Co(II), and Zn(II) complexes, and an orthorhombic system for the Mn(II) complex. Electrochemical properties of the ligand and its metal complexes were investigated in 1 \times 10-3--1 \times 10-4 M DMF and CH3CN solvent in the range 200, 250, and 500 mV s-1 scan rates. The ligand showed both reversible and irreversible processes at these scan rates. In addition, genotoxic properties of the ligand and its complexes were examined.

WOS: 000342449400013, Nanocrystalline Fe - 40at.% Al alloy powders were prepared by using a mechanical alloying (MA) process with a planetary high-energy ball mill. The structural and the morphological properties of the powders were investigated by means of X-ray diffraction (XRD), and scanning electron microscopy (SEM), respectively. A disordered Fe(Al) solid solution with bcc crystal structure was formed after 10 h of MA. Longer MA durations introduced ordering in the alloyed powders. The final crystallite size was found to be as small as 5 nm whereas the internal strain was found to reach a final value of 2.1%. Also, the lattice parameter quickly increased to a maximum value of 0.2926 nm at 30 h of MA, and then decreased to a value of 0.2873 at 80 h of MA. SEM results showed variations in the shapes and the sizes of the particles in the powders at different stages. Furthermore, the microhardness values were found to increase gradually with increasing MA time due to work hardening, grain refinement and solid-solution formation. Magnetic properties such as the saturation magnetization (Ms) and the coercive field (Hc) were calculated from the hysteresis loops, and the results are presented as functions of the MA time., TUBITAK-BIDEPTurkiye Bilimsel ve Teknolojik Arastirma Kurumu (TUBITAK) [2218], The author (B. Avar) would like to thank the TUBITAK-BIDEP 2218 National Research Fellowship Programme.

Elemental mixtures of Al, Cu, Fe powders with the nominal composition of Al70Cu20Fe10 were mechanically alloyed in a planetary ball mill for 80 h. Subsequent annealing of the as-milled powders were performed at 600-800 degrees C temperature range for 4 h. Structural characteristics of the mechanically alloyed Al70Cu20Fe10 powders with the milling time and the heat treatment were investigated by X-ray diffraction (XRD), differential scanning calorimeter (DSC) and differential thermal analysis (DTA). Mechanical alloying of the Al70Cu20Fe10 did not result in the formation of icosahedral quasicrystalline phase (i-phase) and a long time milling resulted in the formation of beta-Al(Cu,Fe) solid solution phase (beta-phase). The i-phase was observed only for short-time milled powders after heat treatment above 600 degrees C. The beta-phase was one of the major phases in the Al70Cu20Fe10 alloy. The w-Al7Cu2Fe1 phase (w-phase) was obtained only after heat treatment of the short-time milled and unmilled samples. The present investigation indicated that a suitable technique to obtain a large amount of quasicrystalline powders is to use a combination of short-time milling and subsequent annealing.

Structural characteristics and thermal behaviour of the conventionally solidified Al-Cu-Fe alloys with nominal compositions of Al(70)Cu(20)Fe(10), Al(65)Cu(20)Fe(15) and Al(63)Cu(25)Fe(12) were investigated by X-ray diffraction, scanning electron microscopy, and differential thermal analysis techniques. Results show that a single quasicrystalline phase forms in a conventionally solidified Al(65)Cu(20)Fe(15) alloy, being thermodynamically stable without phase transition up to the melting point. A cubic AlFe(Cu) solid solution, identified as beta phase, and a cubic AlCu(Fe) solid solution, identified as tau phase, were observed with quasicrystalline phase for Al(63)Cu(25)Fe(12) alloy. Conventional solidification of Al(70)Cu(20)Fe(10) alloy does not result in quasicrystalline phase formation. However, the formation of quasicrystalline phase in conventionally solidified Al(70)Cu(20)Fe(10) alloy was observed after additional annealing at elevated temperature. SEM micrographs for Al(70)Cu(20)Fe(10) and Al(63)Cu(25)Fe(12) alloys after annealing at 700 degrees C for 4 h revealed the formation of pentagonal dodecahedrons in the quasicrystalline phase, with an edge size of about 30 mu m.

This work investigated the quasicrystalline phase formation during heat treatment in the Al63Cu25Fe12 alloy prepared via mechanical alloying, starting from pure elemental powders. The mechanical alloying process was performed at a speed of 300 rpm for times up to 70 hours. The structural evolution of the mechanically alloyed Al63Cu25Fe12 powders at different stages of milling was examined by X-ray diffraction (XRD) and scanning electron microscopy (SEM) techniques. The present results showed that mechanical alloying of the Al63Cu25Fe12 alloy did not result in the quasicrystalline icosahedral phase (i-phase). The long time milling resulted in the formation of an AlFe(Cu) solid solution identified as the beta-phase. In order to examine the structural changes with annealing temperature, the mechanically alloyed powders were heat treated at 600, 700 and 800 degrees C for 4 hours under vacuum. However, the formation of a quasicrystalline phase in the Al63Cu25Fe12 alloy was observed after additional annealing at elevated temperature. In the present work, quasicrystalline phase formation in both the as-milled and heat-treated powders is discussed in detail.