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The microstructure and electrochemical properties of Al–Cu–Fe alloys with the atomic compositions of Al65Cu20Fe15, Al78Cu7Fe15 and Al80Cu5Fe14Si1 have been studied. The alloys were produced by induction melting of pure elements with copper mold casting. The microstructure of the alloys was analyzed by X-ray diffraction and high-resolution transmission electron microscopy. The formation of quasicrystalline phases in the Al–Cu–Fe alloys was confirmed. The presence of intermetallic phases was observed in the alloys after crystallization in a form of ingots and plates. The electrochemical measurements were conducted in 3.5% NaCl solution. The electronic structure of the alloys was determined by X-ray photoelectron spectroscopy. The post corrosion surface of the samples was checked using a scanning electron microscope equipped with the energy-dispersive X-ray detector. It was observed that the Al65Cu20Fe15 alloy had the highest corrosion resistance. The improved corrosion resistance parameters were noted for the plate samples rather than those in the as-cast state. And the hardness of the Al65Cu20Fe15 alloy was significantly higher than the other alloy samples.

The influence of the chemical composition on the crystallization process, amorphous phase formation, and the anticorrosion properties of Al-Zr-Ni-Fe-Y alloys are presented. To reduce the number of experiments, a thermodynamic approach was applied in which the entropy and Gibbs free energy of representative alloys were optimized. The low glass-forming ability of Al-Zr-Ni-Fe-Y alloy systems was related to the crystallization of the Al3Zr phase from the melt. The structural analysis showed that phases containing Ni and Fe, such as Al19Ni5Y3, Al10Fe2Y, and Al23Ni6Y4, played a key role in the formation of amorphous alloys. According to this, the simultaneous addition of Ni/Fe and Y is important to prevent the crystallization of Al-based alloys in the melt. The formation of an amorphous phase in Al80Zr5Ni5Fe5Y5 alloys and the complete amorphization of Al85Ni5Fe5Y5 alloys were responsible for the high corrosion resistance compared with fully crystalline alloys. Moreover, the addition of Y had a significant impact on the anticorrosion properties. The XPS results showed that the alloys tended to form a passive Al2O3 and Y2O3 layer on the surface.

High-entropy ferrites (HEFs) are a new group of high-entropy oxides with unique magnetodielectric properties that offer a wide array of possibilities for high-frequency applications. Various ions were introduced at octahedral sites in the spinel structure to test the role of the high-entropy structure’s formation on its properties. The structural analysis confirmed the formation of single-phase spinel structure even for (FeCoNiMg)(FeCr)2O4 HEF. Dielectric studies showed that introducing Mg2+ and Cr3+ ions increased electrical conductivity and dielectric losses over a wide frequency range. Low frequency (from 0.8 to 1.5 GHz) studies showed that for (FeCo)Fe2O4 and (FeCoNi)Fe2O4 ferrites reflection losses (RL) are negligible, while for both (FeCoNiMg)Fe2O4 and (FeCoNiMg)( FeCr)2O4 ferrites RL higher than 90% were observed. The temperature dependence on the absorption properties was confirmed for (FeCoNiMg)(FeCr)2O4 HEF. The highest absorption window was observed for 343 K, for which RL higher than 90% appears from 1.25 to 1.5 GHz. The possibility of the 3D printing of microwave absorption composites from HEFs was also tested. It was confirmed that the addition of (FeCoNiMg)(FeCr)2O4 HEF drastically increases the absorption properties up to 85.5% at 2.72 GHz for the absorber with the same thickness as made from the pure acrylonitrile butadiene styrene (ABS). Interestingly, the EMI shielding properties of these composites are mainly related to the dielectric losses improved by the addition of entropy stabilised ferrites in 3D printed composites with various ferrite concentrations.

High entropy alloys with variable silicon content were prepared by two different methods to determine the influence of the cooling rate and chemical composition on the structure and properties of the alloys. First, the structure of the alloys was investigated using X-ray diffractometry and electron microscopy and compared with Mössbauer spectra to obtain a comprehensive description of the atom arrangement. The formation ability of the BCC and B2 phases was confirmed. The magnetic properties were examined using a vibrating sample magnetometer and Mössbauer spectroscopy. The corrosion resistance behavior was stu died by electrochemical testing. Our results show that the saturation magnetization tends to decrease with increasing silicon content and that the lowest coercive force was noted for rapidly cooled plates. The highest corrosion resistance in a 3.5% NaCl solution characterizes the AlCoCrFeNiSi0.75 alloy in the form of plates. For which Ecorr and jcorr was equal to − 0.155 V and 0.17 μA/cm2. The addition of Si led to an increase in the hardness of the ingots and plates. For example, AlCoCrFeNiSi0.75 shows 859 HV for the ingot and 727 HV for the plate.

Nanocrystalline magnetic materials are of great interest in order to meet the needs of electronics and electrical engineering. There are many possibilities to modify the synthesis parameters and chemical composition in order to obtain the most desirable magnetic properties and microstructure. The paper discusses an iron-based alloy with the addition of boron lanthanum and aluminium. The alloy was obtained by induction melting and casting with a melt-spinner. The main purpose of the work was to analyze the structure and properties of both the starting alloys in the form of ingots and the obtained tapes. X-ray diffraction (XRD), scanning electron microscopy (SEM), vibration magnetometry (VSM) and microhardness measurements using the Vickers method were carried out.

Biodegradable magnesium alloys with Zn, Yb, Ca and Sr additions are potential materials with increased corrosion resistance in physiological fluids that ensure a controlled resorption process in the human body. This article presents the influence of the use of a high cooling rate on the corrosion behavior of Mg60Zn20Yb15.7Ca2.6Sr1.7 alloy proposed for medical applications. The microstructure of the alloy in a form of high-pressure die-casted plates was presented using scanning electron microscopy in the backscattered electrons (BSEs) mode with energy-dispersive X-ray spectrometer (EDX) qualitative analysis of chemical composition. The crystallization mechanism and thermal properties were described on the basis of differential scanning calorimetry (DSC) results. The corrosion behavior of Mg60Zn20Yb15.7Ca2.6Sr1.7 alloy was analyzed by electrochemical studies with open circuit potential (EOCP) measurements and polarization tests. Moreover, light microscopy and X-ray photoelectron spectroscopy were used to characterize the corrosion products formed on the surface of studied samples. On the basis of the results, the influence of the cooling rate on the improvement in the corrosion resistance was proved. The presented studies are novel and important from the point of view of the impact of the technology of biodegradable materials on corrosion products that come into direct contact with the tissue environment.

Purpose: The article presents the results of research on titanium dioxide synthesized by a sol-gel method that is an easy process enabling the control of the shape and size of particles The purpose of this article is to examine titanium dioxide nanoparticles and thin films deposited by an atomization method. Design/methodology/approach: Titanium dioxide sol was synthesized by using titanium isopropoxide as a precursor. Optical properties were measured by a UV-Vis spectrometer. Structural studies were performed by Raman spectroscopy. Qualitative analysis was performed by the EDS. Surface morphology of nanoparticles and thin films was performed by the SEM technique. Findings: The sol-gel method allows the formation of uniform nanoparticles and thin films of titanium dioxide. The atomization method is a successful method for the deposition of sol to the surface of substrates. Research limitations/implications: The next step in the research will be to investigate the obtained thin films in dye-sensitized solar cells as a semiconductive layer. Practical implications: Unique properties of produced titanium dioxide nanostructural materials have caused the interest in them in such fields as optoelectronics, photovoltaics, medicine and decorative coatings. Originality/value: Titanium dioxide thin films and nanoparticles were synthesized using the sol-gel method and then deposited by the atomization method.

The catalytic activity of non-spherical shaped Fe3O4 nanoparticles synthesized by low cost co-precipitation method was tested. It was presented, that magnetite nanoparticles can be used to degrade not only Rhodamine B and Methylene Blue, but above all cancerogenic azo dye – Sudan I. It was confirmed, that the degradation of Rhodamine B can be described by pseudo-zero-order kinetic model, whereas degradation of Methylene Blue by pseudo-first-order kinetic model. The degradation mechanism of Sudan I by photo-Fenton reaction was proposed. It was noted, that this double-stage process can be associated with hydroxylation of Sudan I and degradation of derivates, such as 4′‑OH‑Sudan I and 6‑OH‑Sudan I. Therefore, it cannot be simple describe by one kinetic model. The introduction of hydroxyl group results in an increase of the absorbance, which in turn is associated with hyperchromic effect.

Purpose: The article presents an analysis of accidents in the selected enterprise from the automotive industry. The analysis includes two workplaces: machine operator and warehouseman. Design/methodology/approach: The analysis of accidents at work in a selected production company includes the period from the beginning of 2016 to half of the 2018 year using the method based on the TOH model. This method determines three factors of accident causes: technical, organizational and human (TOH). Findings: In the paper, the workplaces analysis taking into account activities, type of work, working position and accidents at work is presented. The analysis of work accidents includes the age group, work experience etc. The TOH model determines causes related to accidental events. Research limitations/implications: The accidents at work are the result of a low or undesirable safety culture. Because of that, the safety culture should be constantly developed, maintained and continuously improved. Originality/value: Many methods and procedures can be used to investigate accidents at work. The TOH model is one of them. It determines the direct and indirect causes of accidents. Based on them, the corrective actions can be proposed and implemented.

The Mg-Zn-Ca-(Cu,Au) alloys were considered as resorbable materials for orthopedic short-term implants. The aim of this paper was to determine the influence of Au and Cu addition on corrosion properties of Mg69Zn25Ca5Au1, Mg69Zn25Ca5Au0.5Cu0.5 and Mg69Zn25Ca5Cu1 metallic glasses. The analysis of corrosion results allowed to describe the influence of 0.5 and 1 at.% of Au and Cu on the corrosion resistance in artificial physiological fluid. The Mg69Zn25Ca5Au0.5Cu0.5 and Mg69Zn25Ca5Cu1 metallic glasses exhibit lower corrosion resistance in comparison with Mg69Zn25Ca5Au1 alloy. The increase of Cu content caused the increase of hydrogen evolution volume and the high cathodic activity. The Mg69Zn25Ca5Au1 metallic glass shows the decrease of hydrogen evolution volume and manifests the low corrosion current density and the high polarization resistance, indicating the high corrosion resistance.

New compositions of Ca-based metallic glasses were studied in aim to reduce their rapid degradation in physiological body fluids. The studies were performed on Ca47Mg18Zn35-xAux (x = 0,1,3 at.%) samples in the form of plates. The effect of Au addition on the corrosion behavior of new Ca-based alloys in Ringer's solution was reported. It was found that the Ca47Mg18Zn34Au3 and Ca47Mg18Zn34Au1 glasses show more positive corrosion potential than Ca47Mg18Zn35 alloy. Moreover, samples with Au addition Ca47Mg18Zn34Au3 (0.18 ml/cm2) and Ca47Mg18Zn34Au1 (1.32 ml/cm2) exhibited significantly less hydrogen evolution rates than base alloy Ca47Mg18Zn35 (7.25 ml/cm2) after 7 h. The reduced hydrogen volumes of the alloys with Au addition indicated that they can be used for wide range of biomedical applications.

The effect of iron and yttrium additions on glass forming ability and corrosion resistance of Al88Y8-xFe4+x (x = 0, 1, 2 at.%) alloys in the form of ingots and melt-spun ribbons was investigated. The crystalline multiphase structure of ingots and amorphous-crystalline structure of ribbons were examined by a number of analytical techniques including X-ray diffraction, Mössbauer spectroscopy, and transmission electron microscopy. It was confirmed that the higher Fe additions contributed to formation of amorphous structures. The impact of chemical composition and structure of alloys on their corrosion resistance was characterized by electrochemical tests in 3.5% NaCl solution at 25 °C. The identification of the mechanism of chemical reactions taking place during polarization test along with the morphology and internal structure of the surface oxide films generated was performed. It was revealed that the best corrosion resistance was achieved for the Al88Y7Fe5 alloy in the form of ribbon, which exhibited the lowest corrosion current density (jcorr = 0.09 μA/cm2) and the highest polarization resistance (Rp = 96.7 kΩ∙cm2).

The effect of iron and yttrium additions on glass forming ability and corrosion resistance of Al88Y8-xFe4+x (x = 0, 1, 2 at.%) alloys in the form of ingots and melt-spun ribbons was investigated. The crystalline multiphase structure of ingots and amorphous-crystalline structure of ribbons were examined by a number of analytical techniques including X-ray diffraction, Mössbauer spectroscopy, and transmission electron microscopy. It was confirmed that the higher Fe additions contributed to formation of amorphous structures. The impact of chemical composition and structure of alloys on their corrosion resistance was characterized by electrochemical tests in 3.5% NaCl solution at 25 °C. The identification of the mechanism of chemical reactions taking place during polarization test along with the morphology and internal structure of the surface oxide films generated was performed. It was revealed that the best corrosion resistance was achieved for the Al88Y7Fe5 alloy in the form of ribbon, which exhibited the lowest corrosion current density (jcorr = 0.09 μA/cm2) and the highest polarization resistance (Rp = 96.7 kΩ∙cm2).

The aim of the work was to characterize the structure of Al65Cu20Fe15 alloy obtained with the use of conventional casting and rapid solidification-melt-spinning technology. Based on the literature data, the possibility of an icosahedral quasicrystalline phase forming in the Al-Cu-Fe was verified. Structure analysis was performed based on the results of X-ray diffraction, neutron diffraction, 57Fe M&ouml, ssbauer and transmission electron microscopy. Studies using differential scanning calorimetry were carried out to describe the crystallization mechanism. Additionally, electrochemical tests were performed in order to characterize the influence of the structure and cooling rate on the corrosion resistance. On the basis of the structural studies, the formation of a metastable icosahedral phase and partial amorphous state of ribbon structure were demonstrated. The possibility of the formation of icosahedral quasicrystalline phase I-AlCuFe together with the crystalline phases was indicated by X-ray diffraction (XRD), neutron diffraction (ND) patterns, M&ouml, ssbauer spectroscopy, high-resolution transmission electron microscopy (HRTEM) observations and differential scanning calorimetry (DSC) curves. The beneficial effect of the application of rapid solidification on the corrosive properties was also confirmed.

Amorphous and crystalline magnesium alloys, developed for medical applications – especially implantology – present the characteristics of biocompatible magnesium alloys (Mg-Zn, Mg-Zn-Ca, Mg-Ca etc.). This chapter provides a brief description of the role of magnesium in the human body and the use of Mg in medicine. It presents the concept of using magnesium alloys in medicine (advantages and limitations) and the scope of their potential applications (orthopedic implantology, cardiac surgery etc.). The chapter shows classification of magnesium alloys as potential biomaterials, due to their structure (amorphous, crystalline) and alloying elements (rare earth elements, noble metals etc.). The mechanism and in vitro degradation behavior of magnesium alloys with amorphous and crystalline structures are described. The chapter also discusses the influence of alloying elements (rare earth elements, noble metals) on the in vitro degradation process. It also presents the methods of reducing the degradation rate of magnesium alloys by modifying their surface (application of protective layers).

This article discusses the influence of the thickness of TiO2 films deposited onto MgCa2Zn1 and MgCa2Zn1Gd3 alloys on their structure, corrosion behavior, and cytotoxicity. TiO2 layers (about 200 and 400 nm thick) were applied using magnetron sputtering, which provides strong substrate adhesion. Such titanium dioxide films have many attractive properties, such as high corrosion resistance and biocompatibility. These oxide coatings stimulate osteoblast adhesion and proliferation compared to alloys without the protective films. Microscopic observations show that the TiO2 surface morphology is homogeneous, the grains have a spherical shape (with dimensions from 18 to 160 nm). Based on XRD analysis, it can be stated that all the studied TiO2 layers have an anatase structure. The results of electrochemical and immersion studies, performed in Ringer&rsquo, s solution at 37 &deg, C, show that the corrosion resistance of the studied TiO2 does not always increase proportionally with the thickness of the films. This is a result of grain refinement and differences in the density of the titanium dioxide films applied using the physical vapor deposition (PVD) technique. The results of 24 h immersion tests indicate that the lowest volume of evolved H2 (5.92 mL/cm2) was with the 400 nm thick film deposited onto the MgCa2Zn1Gd3 alloy. This result is in agreement with the good biocompatibility of this TiO2 film, confirmed by cytotoxicity tests.

In this study, possibility of using different thermodynamic parameters, such as: ideal configurational entropy, mixing enthalpy, Gibbs free energy of mixing and mismatch entropy for determining chemical composition of Fe-Co based amorphous alloys was evaluated. The high role of entropy in formation of amorphous phase was confirmed, but maximization of the value of ideal configurational entropy did not allow to obtain fully amorphous alloy. The chemical composition of Fe35Co35Si11B19 amorphous alloy was determined based on minimization the value of Gibbs free energy of formation of amorphous phase – the new parameter proposed in this study. Herein, this new proposed parameter was also used to describe an influence of different chemical elements on glass forming ability of Zr, Cu and Fe based alloys. It was shown, that the Fe based amorphous alloys with the most negative value of Gibbs free energy of formation of amorphous phase were characterized by high thermal stability. The high thermal stability and glass forming ability of Fe35Co35Si11B19 amorphous alloy were confirmed by using differential thermal analysis, X-ray diffraction method, Mossbauer spectroscopy and differential scanning calorimetry. Additionally, influence of isothermal crystallization of Fe35Co35Si11B19 alloy on the structure and magnetic properties was described.

Binary Mg-Ca and ternary Mg-Ca-Zn alloys are a new group of magnesium materials, which can be used in many goods. Among others, biomedical applications of these alloys mainly involved surgical implants in the form of plates or screws. In order to improve mechanical properties and corrosion resistance of Mg-based alloys with Ca and Zn addition in as-cast state a plastic deformation was applied by using the KOBO extrusion method. The microstructure studies conducted by scanning microscopy show that the structure of the alloys after the plastic deformation exhibits banding character and the bands are oriented in the direction of an extrusion. A significant increase of mechanical properties was observed for MgCa5Zn1 alloy. After the plastic deformation, the corrosion potential determined for the MgCa5 and MgCa5Zn1 alloy is shifted into the positive direction, which may suggest the increase of corrosion resistance. Moreover, the MgCa5 alloy in as-cast state was completely dissolved after 288 h of immersion in Ringer’s solution. A volume of hydrogen evolution for the same alloy after plastic deformation showed a value of 35 ml/cm2.

The corrosion behavior of Ca65−xMg10+xZn25 (x = 0,10) and Ca32Mg12Zn38Yb18 alloys was studied by potendiodynamic tests and electrochemical impedance spectroscopy in Ringer's solution. The solution of NaCl, KCl and CaCl2 components reacted with outer layer of alloys and produced corrosion products. The influence of Ca content on the hydrogen volume as a function of time was discussed. The measurements exhibited significantly less hydrogen evolution volumes for Ca55Mg20Zn25 alloy (5.0 ml/cm2) than for Ca65Mg10Zn25 glass (11.3 ml/cm2) after 2 h. The lowest value of hydrogen evolution was observed for Ca32Mg12Zn38Yb18 glass (1.1 ml/cm2). The hydrogen volume for Ca32Zn38Mg12Yb18 sample fulfilled the non-toxic amount of H2, which must be low than ~1 ml/h. The XPS survey spectra for the glassy samples after corrosion test in Ringer's solution represent the surface components. The corrosion products were identified as to be CaCO3, Mg(OH)2, CaO, MgO and ZnO compounds. In addition, the EDS and X-ray analysis of a layer of corrosion products after immersion tests in Ringer's solution identified calcium and ytterbium hydroxide, calcium carbonate and also calcium zinc hydroxide hydrate.

Biodegradable magnesium alloys with Zn, Yb, Ca and Sr additions are potential materials with increased corrosion resistance in physiological fluids that ensure a controlled resorption process in the human body. This article presents the influence of the use of a high cooling rate on the corrosion behavior of Mg60Zn20Yb15.7Ca2.6Sr1.7 alloy proposed for medical applications. The microstructure of the alloy in a form of high-pressure die-casted plates was presented using scanning electron microscopy in the backscattered electrons (BSEs) mode with energy-dispersive X-ray spectrometer (EDX) qualitative analysis of chemical composition. The crystallization mechanism and thermal properties were described on the basis of differential scanning calorimetry (DSC) results. The corrosion behavior of Mg60Zn20Yb15.7Ca2.6Sr1.7 alloy was analyzed by electrochemical studies with open circuit potential (EOCP) measurements and polarization tests. Moreover, light microscopy and X-ray photoelectron spectroscopy were used to characterize the corrosion products formed on the surface of studied samples. On the basis of the results, the influence of the cooling rate on the improvement in the corrosion resistance was proved. The presented studies are novel and important from the point of view of the impact of the technology of biodegradable materials on corrosion products that come into direct contact with the tissue environment.

The spontaneous oxidation of a magnetite surface and shape design are major aspects of synthesizing various nanostructures with unique magnetic and electrical properties, catalytic activity, and biocompatibility. In this article, the roles of different organic modifiers on the shape and formation of an oxidized layer composed of maghemite were discussed and described in the context of magnetic and electrical properties. It was confirmed that Fe3O4 nanoparticles synthesized in the presence of triphenylphosphine could be characterized by cuboidal shape, a relatively low average particle size (9.6 ± 2.0 nm), and high saturation magnetization equal to 55.2 emu/g. Furthermore, it has been confirmed that low-frequency conductivity and dielectric properties are related to surface disordering and oxidation. The electric energy storage possibility increased for nanoparticles with a disordered and oxidized surface, whereas the dielectric losses in these particles were strongly related to their size. The cuboidal magnetite nanoparticles synthesized in the presence of triphenylphosphine had an ultrahigh electrical conductivity (1.02 × 10−4 S/cm at 10 Hz) in comparison to the spherical ones. At higher temperatures, the maghemite content altered the behavior of electrons. The electrical conductivity can be described by correlated barrier hopping or overlapping large polaron tunneling. Interestingly, the activation energies of electrons transport by the surface were similar for all the analyzed nanoparticles in low- and high-temperature ranges.

The corrosion activity of amorphous plates of Ca60Mg15Zn25 alloy was investigated. The biocompatible elements were selected for the alloy composition. The electrochemical corrosion and immersion tests were carried out in a multi-electrolyte fluid and Ringer's solution. Better corrosion behavior was observed for the samples tested in a multi-electrolyte fluid despite the active dissolution of Ca and Mg in Ringer's solution. The experimental results indicated that reducing concentration of NaCl from 8.6 g/dm3 for Ringer's solution to 5.75 g/dm3 caused the decrease of the corrosion rate. The volume of the hydrogen evolved after 480 min in Ringer's solution (40.1 ml/ cm2) was higher in comparison with that obtained in a multi-electrolyte fluid (24.4 ml/cm2). The values of opencircuit potential (EOCP) for the Ca60Mg15Zn25 glass after 1 h incubation in Ringer's solution and a multielectrolyte fluid were determined to be −1553 and −1536 mV vs. a saturated calomel electrode (SCE). The electrochemical measurements indicated a shift of the corrosion current density (jcorr) from 1062 μA/cm2 for the sample tested in Ringer's solution to 788 μA/cm2 for the specimen immersed in a multi-electrolyte fluid. The corrosion products analysis was conducted by using the X-ray photoelectron spectroscopy (XPS). The corrosion products were identified to be CaCO3, Mg(OH)2, CaO, MgO and ZnO. The mechanism of corrosion process was proposed and described based on the microscopic observations. The X-ray diffraction and Fourier transform infrared spectroscopy (FTIR) also indicated that Ca(OH)2, CaCO3, Zn(OH)2 and Ca(Zn(OH)3)2·2H2O mainly formed on the surface of the studied alloy., The work was supported by National Science Centre under research project no.: 2013/09/B/ST8/02129 .

The quaternary Ca 50 Mg 20 Cu 25 Zn 5 metallic glass in the form of ribbons and plates was successfully fabricated by melt-spinning and copper-mold casting. The structure characterization of the alloy in as-cast state was performed by using X-ray diffraction method. The Reverse Monte Carlo modeling was carried out to obtain structural model of the alloy in the form of ribbon. Moreover, the corrosion behavior of glassy plates was studied by electrochemical measurements and immersion tests in 1, 2 and 3.5% NaCl solution (pH = 5.4) at room temperature. As suspected the lowest corrosion activity of the alloy was observed in 1% NaCl solution. The post-corrosion tests were conducted by scanning electron microscopy and energy-dispersive X-ray spectroscopy to examine the corrosion products and chemical composition of the corroded surfaces. The XPS measurements were used to better understand corrosion behavior of the alloy after immersion during the open-circuit conditions. The corrosion surface products were identified to be CaO, MgO, Mg(OH) 2 and CaCO 3 components. The ZnO and CuO compounds were formed on the surface of glassy samples.

The structure of a multicomponent metallic glass, Mg65Cu20Y10Ni5, was investigated by the combined methods of neutron diffraction (ND), reverse Monte Carlo modeling (RMC) and high-resolution transmission electron microscopy (HRTEM). The RMC method, based on the results of ND measurements, was used to develop a realistic structure model of a quaternary alloy in a glassy state. The calculated model consists of a random packing structure of atoms in which some ordered regions can be indicated. The amorphous structure was also described by peak values of partial pair correlation functions and coordination numbers, which illustrated some types of cluster packing. The N = 9 clusters correspond to the tri-capped trigonal prisms, which are one of Bernal’s canonical clusters, and atomic clusters with N = 6 and N = 12 are suitable for octahedral and icosahedral atomic configurations. The nanocrystalline character of the alloy after annealing was also studied by HRTEM. The selected HRTEM images of the nanocrystalline regions were also processed by inverse Fourier transform analysis. The high-angle annular dark-field (HAADF) technique was used to determine phase separation in the studied glass after heat treatment. The HAADF mode allows for the observation of randomly distributed, dark contrast regions of about 4–6 nm. The interplanar spacing identified for the orthorhombic Mg2Cu crystalline phase is similar to the value of the first coordination shell radius from the short-range order.

Fe-based nanocrystalline alloys were prepared by the melt-spinning technique and characterized by X-ray diffraction, magnetostatic and Mössbauer effect methods. The Mössbauer spectroscopy allows to study the local environment of the Fe atoms in the investigated Fe80 xNixB20 (x 8, 16, 24, 28) compounds and showing the changes in the structure due to the changing of Ni addition. Combination of X-ray diffraction and Mössbauer spectroscopy results confirm formation of different number of phase complex, including the -FeNi, -FeNi, FeB, Fe2B, Fe3B in the investigated materials together with increase of Ni content.

Magnesium alloys are considered as potential biomaterials for use in orthopedic implantology. The main barrier to the use of Mg alloys in medicine is their overly fast and irregular degradation in body fluids. The use of protective calcium phosphate coatings to increase the corrosion resistance of Mg alloy (AM50 alloy: 4 wt.% Al, 0.3 wt.% Mn, 0.2 wt.% Zn, rest Mg) was examined in this study. The scientific goal of the study was the assessment of the influence of calcium phosphate layer morphology on the corrosion process in Ringer&rsquo, s solution. Modification of the coating morphology was obtained by changing the chemical composition of the phosphatizing bath using NaOH (NaAM50 sample) or ZnSO4 (ZnAM50 sample). In practice, a more dense and uniform coating could be obtained by the immersion of AM50 alloy in a solution containing ZnSO4 (ZnAM50 sample). In this study, an adhesion test performed on the ZnAM50 sample indicated that the critical load was 1.35 N. XRD phase analysis confirmed that the obtained coatings included dicalcium phosphate dihydrate (CaHPO4*2H2O). The coatings prepared on the NaAM50 and ZnAM50 samples are effective barriers against the progress of corrosion deeper into the substrate. After 120 h immersion in Ringer&rsquo, s solution, the volume of the evolved hydrogen was 5.6 mL/cm2 for the NaAM50 and 3.4 mL/cm2 for the ZnAM50 sample.

In this work, the compositions of Al-Ni-Fe alloys were determined based on thermodynamic parameters optimization. Decagonal quasicrystalline phase D -Al70.83Fe9.83Ni19.34 was identified in the alloy with the highest Gibbs free energy of solid solution formation, i.e., Al71Ni24Fe5. According to this, the configurational entropy and enthalpy of solid solution formation must reach equilibrium to form quasicrystals in Al-Ni-Fe alloys. Differential thermal analysis and X-ray diffraction were used to describe the crystallization mechanism as a function of Fe concentration. 57Fe Mossbauer spectroscopy was used to describe the Fe local environment in crystalline alloys and quasicrystals. Moreover, the influence of quasicrystalline phases on improving the corrosion resistance was investigated. Quasicrystalline Al71Ni24Fe5 alloy had a six-times lower corrosion rate than its crystalline counterparts. Although this alloy showed the best corrosion resistance, all high-pressure cast Al-Fe-Ni alloys displayed improved corrosion resistance.

The main aim of this paper was to produce amorphous ribbons with specified composition with the use of various process parameters and X-ray qualitative and quantitative phase analysis after casting and heat treating. Station for ultra-fast cooling of the molten alloy with high vacuum pumps designed for the production of metallic glasses in the form of ribbons with the use of Buhler Melt Spinner SC was used. The X-ray qualitative and quantitative phase analysis, microscopic observation, microhardness and thermal properties tests of the investigated ribbons were conducted. Based on experimental data the discussion on the correlation between casting process parameters, phase and quantitative composition and heat treatment was carried out.

The paper presents the structural analysis of Fe62􀀀xCoxNb8B30 metallic glasses (x = 0; 20) in as-cast and after crystallization state. The studies were performed on metallic glasses of ribbon form with thickness of 0.05 and 0.06 mm. The structure analysis of the samples in as-cast state and phase analysis of studied alloys after annealing was carried out by the X-ray diffraction methods. Moreover, the Mössbauer spectroscopy was also used to investigate the local structure for examined alloys. The soft magnetic properties examination covered the initial magnetic permeability. The after-effects of magnetic permeability were also conducted.

In this work, bulk metallic glasses Ca60Mg20Zn20 (BMGs) in the form of plates were successfully prepared by the high-pressure die casting. The glassy alloy with the biocompatible elements Ca, Mg and Zn was produced as bioresorbable material for potential biomedical applications. The structure of bulk amorphous samples was confirmed by a conventional X-ray diffraction and a differential scanning calorimetry (DSC) method. The corrosion behavior of the glassy samples was studied by electrochemical measurements and immersion tests in a physiological and Ringer's solution. The results of immersion show that the volume of H2 evolved after 480 min in Ringer's solution (24.9 ml/cm2) is higher in comparison with the measurements conducted in a physiological fluid (13.1 ml/cm2). The open-circuit potential (EOCP) for the Ca60Mg20Zn20 glassy sample after 60 min of incubation in Ringer's solution and a physiological fluid was found to be − 1543 and − 1566 mV vs. a saturated calomel electrode (SCE). The electrochemical measurements indicated a shift of the corrosion potential (Ecorr) from − 1551 mV for sample tested in a physiological fluid to − 1527 mV for specimen immersed in Ringer's solution. In order to further understand the corrosion behavior of the studied material the X-ray photoelectron spectroscopy (XPS) measurements were used to determine the elemental composition of the corrosion products after polarization. The corrosion products were identified to be CaCO3, Mg(OH)2, CaO, MgO and ZnO. The uniform corrosion mechanism is considered. The energy-dispersive X-ray spectroscopy (EDS) results suggest that calcium and magnesium hydroxides and calcium oxides were mainly formed on the surface of studied alloy. The post-experiment analyses of surface morphology were conducted by a scanning electron microscopy.