332 results on '"Phase formation"'
Search Results
2. Exploring the diffusion wear mechanism between SiAlON and Inconel 718: Interfacial reactions and thermal properties in diffusion couples.
- Author
-
Choi, Jae-Hyeong, Lee, Sung-Min, and Kim, Seongwon
- Subjects
- *
INTERFACIAL reactions , *SIALON , *THERMAL properties , *HEAT conduction , *THERMAL conductivity - Abstract
During the machining of Inconel 718 using SiAlON ceramics, the tool life can be significantly influenced by diffusion wear. To investigate this crucial wear behavior, this study focuses on the thermochemical interactions in the diffusion couple between SiAlON ceramics and Inconel 718 superalloy. So, we examine the microstructural characteristics and phase formation behavior in the reacted layer between these two materials. The interfaces between these two materials exhibit distinguishable elemental contrasts and phase formations. Particularly, the phases indicate vitrification or devitrification in the diffusion layer, influenced by the chemical composition. This issue in the diffusion couple was analyzed with thermophysical properties using light flash analysis (LFA). After, it was confirmed that the vitrification of the diffusion layer can be induced by the conduction behavior of heat trapped between SiAlON and Inconel 718 during supercooling. These characterizations verify that the devitrification of the welding layer (diffusion layer), resulting from the reaction between SiAlON ceramics and Inconel 718 superalloy, can depend on the thermal conductivity of the prepared ceramics. Furthermore, we discovered a possibility that this could contribute to improving tool performance by suppressing diffusion wear. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
3. Solid solutions in disulfide systems Re(IV)S2–Ti(IV)S2, Re(IV)S2–Mo(IV)S2, and Re(IV)S2–W(IV)S2
- Author
-
E. I. Efremova, M. A. Lazov, M. R. Kobrin, and V. V. Fomichev
- Subjects
solid solutions ,intercalates ,transition metal disulfides ,phase formation ,crystal lattice ,binding energies ,Chemistry ,QD1-999 - Abstract
Objectives. Chalcogenides of transition elements with low oxidation states, as well as their substituted derivatives, remain a poorly studied class of chemical compounds. Rhenium disulfide has many distinctive features and great application potential as a new twodimensional semiconductor. This is due to its unusual structure and unique anisotropic properties. The presence of weak interlayer bonding and a unique distorted octahedral (1T) structure suggests the possibility of creating new phases on its basis. The aim of this work is to obtain and study phases in systems Re(IV)S2–Ti(IV)S2, Re(IV)S2–Mo(IV)S2, and Re(IV)S2–W(IV)S2.Methods. The samples were obtained by high-temperature solid-phase ampoule synthesis in a vacuum. The study was carried out using X-ray phase analysis and X-ray photoelectron spectroscopy.Results. The regions of existence of solid solutions, intercalates and two-phase regions in the resulting systems were established.Diffraction patterns were obtained for the new phases and the crystal lattice parameters were calculated. Based on data relating to the binding energies of core electrons with the nucleus, the study showed the valence states of the elements after synthesis. The study also confirmed that all phases obtained as a result of synthesis contain transition elements in the oxidation state (IV).Conclusions. Intercalated solid solutions are formed in areas rich in rhenium, while in areas close to titanium and molybdenum disulfides, intercalated phases are attained. In the ReS2–WS2 system there is a region of solid solutions, including 30, 50, and 70 mol % rhenium disulfide. Their structure is a polymorphic modification of the structure of the original components. The presence of rhenium, molybdenum, and tungsten in these phases in the oxidation state (+IV) was confirmed. The data obtained on phase formation in dichalcogenide systems can be practically used in the creation of materials with unique electronic, magnetic, and optical properties with a wide range of applications.
- Published
- 2024
- Full Text
- View/download PDF
4. Magnetic properties, structural investigation and optical studies of Er3+doping Cd-Mg spinel ferrite.
- Author
-
Venu, S., Prasad, N. V. Krishna, Kumar, N. Hari, ChandrababuNaidu, K., Vinod, G., and Ravinder, D.
- Subjects
- *
MAGNETIC properties , *RARE earth ions , *CHEMICAL formulas , *LATTICE constants , *METAL bonding - Abstract
The effect of using citrate-gel auto combustion method to substitute erbium rare-earth ion on magnetism cadmium composition of chemicals formula Cd0.2Mg0.8ErxFe2-xO4 (CMEF) (x = 0.000, 0.005, 0.010, 0.015, 0.020, and 0.025). Synthesized powder were sintered for 4 h at 600 °C after the crushed powders were calcined. These CMEF nanoferrites' structural and magnetic properties were investigated using P-XRD, E-DAX, FE-SEM, HR-TEM, FT-IR, and VSM investigations. Analysis has been done on the benefits of the crystallite size, phase, and various structural features of CMEF using P-XRD data. The assessed crystalline size is within the range of 20.43 nm and 24.30 nm, while the lattice constant ranges from 8.34 to 8.37 Å. photos obtained with the HR-TEM showed that the Er3+ doped Mg-Cd nanoferrites had particle sizes between 10.5 and 20.7 nm, while the FE-SEM photos showed grain sizes between 19.3 nm and 40.3 nm. With the help of elemental analysis (%) from EDAX, and the CMEF of elements that comprise the given chemical composition were thoroughly analysed without interfering substances. The spinel structure was confirmed by the presence of two stretching bonds between metal nitrates and function groups, as shown by the FT-IR spectra that were obeyed. VSM generates the characteristic hysteresis loops of the synthesised sample at 300 K temperature in the magnetic experiments. The findings showed that at 300 K, all of the MCEF nanoferrites exhibited ferromagnetic behaviour. Substantial magnetization was reached at 300 K for 20–18.48 emu/g). The Hc values were determined to lie between 107.46 and 129.53 Oe, while the squareness or remanent ratio values at 300 K varied. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
5. STUDY OF THE PHASE FORMATION OF TRANSPARENT MAGNESIUM ALUMINOSILICATE GLASS-CERAMIC MATERIALS.
- Author
-
Savvova, O. V., Tur, O. H., Fesenko, O. I., Babich, O. V., Smyrnova, Yu. O., and Hordiichuk, V. M.
- Subjects
OPTICAL materials ,TRANSPARENCY (Optics) ,PULSED lasers ,NANOSTRUCTURED materials ,CORDIERITE ,GLASS-ceramics ,Q-switched lasers - Abstract
Current trends in the development of materials for optics and laser technology were analyzed. The prospects of creating passively Q-switched Yb-Er glass lasers with eye-safe emission wavelengths based on glass-ceramic magnesium aluminosilicate materials for compact pulsed lasers were established. The main types of transparent glass-ceramic materials were analyzed and the main criteria for the synthesis of transparent nanostructured glass-ceramic materials with a crystalline phase content of approximately 70-80 vol.% were substantiated. Compositions of magnesium aluminosilicate glasses were synthesized and the differences of compositions with different types of optical transparency were determined, taking into account their thermal prehistory. The mechanism of phase formation and the differences of ΣMgO, Al
2 O3 , MgO/Al2 O3 and ΣRO2 in their composition, which determine the character of crystallization, optical transparency and density under the conditions of heat treatment with a duration of 0.5 and 6 hours, were studied. The developed magnesium aluminosilicate glasses can be used as a basis for the creation of protective and functional high-strength nanostructured glass-ceramic materials based on spinel or cordierite with adjustable optical transparency for optics and laser technology. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
6. Impact of In element on the melting point and properties of Pb-56Bi-In eutectic alloy.
- Author
-
Luo, Fang, Huang, Feihong, Hu, Jinxin, and Yang, Youdong
- Abstract
Based on advanced first-principle calculations driven by density functional theory, our study used fusion casting techniques to incorporate minute quantities of In into the conventional Pb-56Bi eutectic alloy. Detailed examination identified the critical parameters of the prepared materials, including melting point, phase formation and microstructure. The initial Pb56Bi alloy had a melting point of 125°C, while the inclusion of In yielded Pb-56Bi-XIn (X represents the percentage of In element) and decreased the melting temperature to 85.7°C–119.7°C. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
7. Towards a Sustainable Laser Powder Bed Fusion Process via the Characterisation of Additively Manufactured Nitinol Parts.
- Author
-
Obeidi, Muhannad Ahmed, Healy, Paul, Alobaidi, Hasan, Bourke, Declan, and Brabazon, Dermot
- Subjects
NICKEL-titanium alloys ,METAL powders ,LASERS ,THREE-dimensional printing ,ENERGY density ,SHAPE memory alloys - Abstract
Is additive manufacturing (AM) a sustainable process? Can the process be optimised to produce sustainable AM parts and production techniques? Additive manufacturing offers the production of parts made of different types of materials in addition to the complex geometry that is difficult or impossible to produce by using the traditional subtractive methods. This study is focused on the optimisation of laser powder bed fusion (L-PBF), one of the most common technologies used in additive manufacturing and 3D printing. This research was carried out by modulating the build layer thickness of the deposited metal powder and the input volumetric energy density. The aim of the proposed strategy is to save the build time by maximizing the applied layer thickness of nitinol powder while retrieving the different AM part properties. The saving in the process time has a direct effect on the total cost of the produced part as a result of several components like electric energy, inert gas consumption, and labour. Nickel-rich nitinol (52.39 Ni at.%) was selected for investigation in this study due to its extremely high superplastic and shape memory properties in addition to the wide application in various industries like aerospace, biomedical, and automotive. The results obtained show that significant energy and material consumption can be found by producing near full dens AM parts with limited or no alteration in chemical and mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
8. Influence of Solidification Rate and Impurity Content on 5/7-Crossover Alloys
- Author
-
Samberger, Sebastian, Stemper, Lukas, Uggowitzer, Peter J., Tosone, Ramona, Pogatscher, Stefan, and Wagstaff, Samuel, editor
- Published
- 2024
- Full Text
- View/download PDF
9. Influence of Increased Fe, Cu, and Zn Concentrations on Phase Formation in Aluminum A356 (AlSi7Mg0.3) Alloy
- Author
-
Beyer, T., Kleinhans, R., Rosefort, M., Klan, S., Siemund, A., Decker, P., Volk, W., and Wagstaff, Samuel, editor
- Published
- 2024
- Full Text
- View/download PDF
10. Phase Formation, Polymorphism, Optical Properties, and Conductivity of Nd2WO6-Based Compounds and Solid Solutions
- Author
-
Baldin, E. D., Lyskov, N. V., Rassulov, V. A., and Shlyakhtina, A. V.
- Published
- 2024
- Full Text
- View/download PDF
11. Microstructure, Mechanical Properties and Corrosion Resistance of the Mo0.5V0.5NbTiZrx High-Entropy Alloys with Low Thermal Neutron Sections
- Author
-
Xiang, Chao, Han, En-Hou, Zhang, Zhiming, Fu, Huameng, Zhang, Haifeng, Wang, Jianqiu, and Hu, Guodong
- Published
- 2024
- Full Text
- View/download PDF
12. Effect of the addition of Ni and Cu on solidification microstructure evolution of Al-5Si-0.5Mg alloys
- Author
-
Vončina, Maja, Balaško, Tilen, Petrič, Mitja, Medved, Jožef, Modrijan, Ožbej, and Li, Jiehua
- Published
- 2024
- Full Text
- View/download PDF
13. Development of High-Entropy Alloys as Bond Coats: A Thermodynamic and Kinetic Perspective
- Author
-
Anupam, Ameey, Guruvidyathri, K., and Vaidya, Mayur
- Published
- 2024
- Full Text
- View/download PDF
14. Local lattice distortions and chemical short-range order in MoNbTaW
- Author
-
Andrea Fantin, Anna Maria Manzoni, Hauke Springer, Reza Darvishi Kamachali, and Robert Maaß
- Subjects
High entropy alloys ,short-range order ,local lattice distortions ,EXAFS ,phase formation ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Extended X-ray absorption fine structure (EXAFS) conducted on an equiatomic MoNbTaW bcc medium-entropy alloy that was annealed at 2273 K reveals unexpectedly small 1st and 2nd shell element-specific lattice distortions. An experimental size-mismatch parameter, [Formula: see text], is determined to be ca. 50% lower than the corresponding calculated value. Around W, short-range order (SRO) preferring 4d elements in the 1st and 2nd shells persists. A Nb-W ordering is found, which is reminiscent of ordering emerging at lower temperatures in the B2(Mo,W;Ta,Nb)- and B32(Nb,W)-phases. With high-temperature ordering preferences in fcc also foreshadowing low-temperature phase, these findings suggest a general feature of high-temperature SRO.
- Published
- 2024
- Full Text
- View/download PDF
15. Electrochemical phase formation via a supercooled liquid state stage: phenomenon description and applications.
- Author
-
Girin, Oleg B.
- Subjects
- *
CRYSTAL texture , *ALLOYS , *METALLURGY , *SUPERCOOLED liquids , *SURFACE coatings , *SURFACE morphology , *METALLIC glasses - Abstract
A review of the author's works proving the existence of the phenomenon of the electrochemical phase formation in metals and alloys via a supercooled liquid state stage is presented. This review presents all the stages of establishing the above phenomenon in chronological order, as well as examples of its scientific and practical application. The theoretical prediction of the phenomenon, its experimental observation, theoretical substantiation, and some experimental proofs confirming its existence are considered in detail. The mechanism and thermodynamic model of crystallographic texture formation in electrochemical coatings, developed on the basis of the concepts of the phase formation in electrodepositing metals/alloys, taking into account the intermediate stage of the supercooled liquid state, are discussed. Some areas of the practical application of the phenomenon in basic industries (metallurgy, power engineering, and space engineering), concerning the development of the technologies for obtaining electrochemical films/coatings/foils with enhanced properties, are presented. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
16. Local lattice distortions and chemical short-range order in MoNbTaW.
- Author
-
Fantin, Andrea, Manzoni, Anna Maria, Springer, Hauke, Kamachali, Reza Darvishi, and Maaß, Robert
- Subjects
EXTENDED X-ray absorption fine structure ,TANTALUM - Abstract
Extended X-ray absorption fine structure (EXAFS) conducted on an equiatomic MoNbTaW bcc medium-entropy alloy that was annealed at 2273 K reveals unexpectedly small 1
st and 2nd shell element-specific lattice distortions. An experimental size-mismatch parameter, $ \delta _{exp} $ δ exp , is determined to be ca. 50% lower than the corresponding calculated value. Around W, short-range order (SRO) preferring 4d elements in the 1st and 2nd shells persists. A Nb-W ordering is found, which is reminiscent of ordering emerging at lower temperatures in the B2(Mo,W;Ta,Nb)- and B32(Nb,W)-phases. With high-temperature ordering preferences in fcc also foreshadowing low-temperature phase, these findings suggest a general feature of high-temperature SRO. A medium-entropy MoNbTaW bcc alloy annealed at 2273 K shows still signs of short-range ordering which relate to its segregational behavior at lower temperatures, corroborating observations on fcc alloys. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
17. Characterization of Mn 5 Ge 3 Contacts on a Shallow Ge/SiGe Heterostructure.
- Author
-
Hutchins-Delgado, Troy A., Addamane, Sadhvikas J., Lu, Ping, and Lu, Tzu-Ming
- Subjects
- *
SPINTRONICS , *ENERGY dispersive X-ray spectroscopy , *ELECTRON energy loss spectroscopy , *SCHOTTKY barrier , *QUANTUM wells , *QUANTUM Hall effect , *SCHOTTKY barrier diodes , *X-ray imaging , *SCANNING transmission electron microscopy - Abstract
M n 5 G e 3 is a ferromagnetic phase of the Mn-Ge system that is a potential contact material for efficient spin injection and detection. Here, we investigate the creation of M n 5 G e 3 -based contacts on a Ge/SiGe quantum well heterostructure via solid-state synthesis. X-ray diffraction spectra fitting indicates the formation of M n 5 G e 3 -based contacts on bulk Ge and Ge/SiGe. High-resolution scanning transmission electron microscopy imaging and energy dispersive X-ray spectroscopy verify the correct M n 5 G e 3 -based phase formation. Schottky diode measurements, transmission line measurements, and Hall measurements reveal that M n 5 G e 3 -based contacts serve as good p-type contacts for Ge/SiGe quantum well heterostructures due to having a low Schottky barrier height of 0.10 e V (extracted from a M n 5 G e 3 /n-Ge analogue) and a contact resistance in the order of 1 k Ω. Furthermore, we show that these electrical characteristics have a gate-voltage dependence, thereby providing tunability. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
18. Microstructural Evolution and Magnetocaloric Properties of Cold Plastically Deformed LaFe10.9Co0.7Si1.4 Compound.
- Author
-
Chen, RuZhao, Fu, Bin, Han, Jie, and Hu, Jie
- Subjects
MAGNETOCALORIC effects ,MAGNETIC cooling ,MAGNETIC entropy ,MAGNETIC fields ,MAGNETICS - Abstract
To optimize the formation of the magnetocaloric 1:13 phase in La(Fe,Si)
13 -based compounds, a method to improve the preparation process and promote the practical application of magnetic refrigeration is proposed. The LaFe10.9 Co0.7 Si1.4 and LaFe13.1 Co0.7 Si1.4 samples were plastically deformed to different degrees by cold compression at room temperature. Subsequently, grain structure, phase composition, and magnetocaloric effects were systematically investigated. The results demonstrated that the pre-deformation process can effectively increase the number of grains per unit volume and homogenize the grain size. Using the same annealing temperature and time, the 1:13 phase in the pre-compressed samples was much higher than that in the uncompressed samples, whereas the compression deformation did not cause an uneven elemental distribution. Compared to LaFe13.1 Co0.7 Si1.4 , the LaFe10.9 Co0.7 Si1.4 compound obtained by the same preparation process has a higher magnetocaloric phase ratio. After short annealing for 3 days, the Curie temperature (TC ) of 40% pre-deformed LaFe10.9 Co0.7 Si1.4 sample reaches 303 K, and the magnetic entropy change of 5.30 and 10.55 J/kg K under 2 and 5 T magnetic fields is observed. The good magnetic refrigeration-related performance makes the 40% pre-deformed LaFe10.9 Co0.7 Si1.4 alloy a potential candidate for room temperature magnetic refrigeration. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
19. Metastable phase formation of (Mo,Cr)2AlB2 MAB phase thin films revealed by theory and experiments
- Author
-
P. J. Pöllmann, D. Bogdanovski, S. Lellig, P. Schweizer, M. Hans, C. Azina, S. Karimi Aghda, P. Zöll, D. M. Holzapfel, D. Primetzhofer, S. Kolozsvári, P. Polcik, J. Michler, and J. M. Schneider
- Subjects
MAB phase ,density functional theory ,magnetron sputtering ,phase formation ,thin film ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
A (Mo0.24Cr0.76)0.40Al0.32B0.28 thin film was deposited by direct current magnetron sputtering at 600 °C substrate temperature. Analysis by X-ray diffraction, energy-dispersive X-ray spectroscopy, elastic recoil detection analysis, and high-resolution scanning transmission electron microscopy revealed the formation of the previously unreported (Mo,Cr)2AlB2 MAB phase, along with Cr3AlB4, CrB4, and Mo, in good agreement with density functional theory (DFT) calculations. Hence, the MAB phase family in the Mo-Cr-Al-B system is extended by a novel, quaternary member.
- Published
- 2024
- Full Text
- View/download PDF
20. Strategies for optimizing the single GdSrFeO4 phase synthesis
- Author
-
Kenges Kairat Maratuly and Tugova Ekaterina Alekseevna
- Subjects
rare earth ferrites ,phase formation ,solid state reactions ,thermal stability ,tec ,Chemistry ,QD1-999 - Abstract
This work provides data on strategies for single GdSrFeO4 phase solid state synthesis. Earlier works have shown that under the solid-state synthesis conditions, the GdSrFeO4 preparation is hampered by the formation of non-target product: Gd2SrFe2O7. This work approach led to the solid-phase synthesis GdSrFeO4 scheme change. GdSrFeO4 was characterized by X-Ray, scanning electron microscopy/energy dispersive X-ray spectroscopy, dilatometry and complex thermal analysis methods. GdSrFeO4 is stable in the wide range of studied temperatures 40–1,400°C in air. The sintering start temperature was determined to be 985°C. GdSrFeO4 has a thermal expansion coefficient of 30 × 10−6 K−1. The thermal stability is excellent for further investigation and potential for application of the materials as SOFC, for example. The study of catalytic stability of the obtained GdSrFeO4 is to be a subject of future work as well.
- Published
- 2023
- Full Text
- View/download PDF
21. Compositional correlations to intrinsic magnetic properties in binary and Ti-alloyed MnAl magnetic alloys
- Author
-
Zhao, Shuang, Dong, Ying, Jia, Yu-xiao, Xu, Yi-chen, and Wu, Yu-ye
- Published
- 2024
- Full Text
- View/download PDF
22. Influence of different temperatures and pH on structural, morphological, and electrochemical properties of Cu2O thin films by electrodeposition in acidic media.
- Author
-
Du, Jie, Li, Jingjing, and Liu, Kegao
- Subjects
- *
THIN films , *COPPER films , *ELECTROPLATING , *DIFFRACTION patterns , *SCANNING electron microscopy , *CUPROUS oxide - Abstract
The present work describes the effect of deposition temperatures and pH values on structural, morphological, and electrochemical properties of cuprous oxide (Cu2O) thin films deposited on the conductive SnO2 glass substrates by using electrodeposition technique in an acidic system. The chronoamperometry curve of the solution was tested on an electrochemical workstation. X-ray diffraction patterns indicate that the deposited films have better crystallinity which is deposited at the deposition temperature of 50 °C and pH value of 5–6. Scanning electron microscopy displays that surface morphology of the deposited films varied greatly with the deposition temperature and pH value rising. The results of quantitative study of the target product films by Energy Dispersive Spectrometer (EDS) show that they are all in line with the element content ratio of Cu2O. By measuring the resistivity and conductivity of the deposited films, it was found to be in the semiconductor range. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
23. Mechanism of Sm2MoO6 Phase Formation from a Mechanically Activated Oxide Mixture.
- Author
-
Baldin, E. D., Vorobieva, G. A., Kolbanev, I. V., Lyskov, N. V., and Shlyakhtina, A. V.
- Abstract
The mechanism of phase formation from the initial and the mechanically activated (m/a) mixture of Sm
2 O3 +MoO3 oxides is studied by differential scanning calorimetry (DSC) in an oxygen atmosphere. It is shown that different mechanisms of samarium oxymolybdate synthesis are realized in these two cases. As a result of the mechanochemical action at room temperature, a nanosized mixture of Sm2 (MoO4 )3 and Sm2 O3 is formed. Upon heating, Sm2 (MoO4 )3 is crystallized at the first stage and its interaction with Sm2 O3 in the second stage at 900°C leads to the synthesis of oxymolybdate Sm2 MoO6 with a scheelite structure, and this structure type is stable up to 1400°C. The kinetic experiment in a DSC cell shows only an apparent similarity of the phase formation mechanism with a decrease of the main exoeffects by 70°C for a m/a mixture of oxides. At the same time, the study of the mechanism of phase formation by isothermal exposure at different temperatures reveals the main advantages of ceramic synthesis from an activated oxide mixture. The total conductivity of Sm2 MoO6 with a scheelite structure, which turned out to be of the p-type (1 × 10−6 S/cm at 600°C), is studied. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
24. Preparation of Nanoceramic Material Based on Bismuth Titanate Bi2Ti4O11.
- Author
-
Lomanova, N. A.
- Subjects
- *
BISMUTH titanate , *ELECTRONIC equipment , *SOLUTION (Chemistry) , *BISMUTH , *NANOCRYSTALS , *SINTERING - Abstract
The functional characteristics of materials based on bismuth titanate Bi2Ti4O11 largely depend on the synthesis conditions. The preparation of nanocrystals of this compound is timely because of the problem with miniaturization of electronic components. The features of phase formation and the optimal conditions for the formation of a nanoceramic material based on Bi2Ti4O11 via coprecipitation from salt solutions are studied in the present work. The morphological features, formation temperature, and activation of sintering of the material were established. [ABSTRACT FROM AUTHOR]
- Published
- 2024
- Full Text
- View/download PDF
25. Metastable phase formation of (Mo,Cr)2AlB2 MAB phase thin films revealed by theory and experiments.
- Author
-
Pöllmann, P. J., Bogdanovski, D., Lellig, S., Schweizer, P., Hans, M., Azina, C., Karimi Aghda, S., Zöll, P., Holzapfel, D. M., Primetzhofer, D., Kolozsvári, S., Polcik, P., Michler, J., and Schneider, J. M.
- Subjects
THIN films ,FILM theory ,SCANNING transmission electron microscopy ,DC sputtering ,DENSITY functional theory - Abstract
A (Mo
0.24 Cr0.76 )0.40 Al0.32 B0.28 thin film was deposited by direct current magnetron sputtering at 600 °C substrate temperature. Analysis by X-ray diffraction, energy-dispersive X-ray spectroscopy, elastic recoil detection analysis, and high-resolution scanning transmission electron microscopy revealed the formation of the previously unreported (Mo,Cr)2 AlB2 MAB phase, along with Cr3 AlB4 , CrB4 , and Mo, in good agreement with density functional theory (DFT) calculations. Hence, the MAB phase family in the Mo-Cr-Al-B system is extended by a novel, quaternary member. In this work, quaternary MAB phase (Mo,Cr)2 AlB2 is synthesized experimentally for the first time. Its metastable formation is rationalized by density functional theory calculations. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
26. Preparation of Nanoceramic Material Based on Bismuth Titanate Bi2Ti4O11.
- Author
-
Lomanova, N. A.
- Subjects
BISMUTH titanate ,ELECTRONIC equipment ,SOLUTION (Chemistry) ,BISMUTH ,NANOCRYSTALS ,SINTERING - Abstract
The functional characteristics of materials based on bismuth titanate Bi
2 Ti4 O11 largely depend on the synthesis conditions. The preparation of nanocrystals of this compound is timely because of the problem with miniaturization of electronic components. The features of phase formation and the optimal conditions for the formation of a nanoceramic material based on Bi2 Ti4 O11 via coprecipitation from salt solutions are studied in the present work. The morphological features, formation temperature, and activation of sintering of the material were established. [ABSTRACT FROM AUTHOR]- Published
- 2024
- Full Text
- View/download PDF
27. Distinctive Characteristics of Multilayer and Single-Layer Coatings under High-Temperature Testing.
- Author
-
Vorontsov, A. V., Filippov, A. V., Shamarin, N. N., Moskvichev, E. N., Novitskaya, O. S., Knyazhev, E. O., Denisova, Yu. A., Leonov, A. A., and Denisov, V. V.
- Abstract
Layer-by-layer deposition of zirconium and chromium nitrides is a promising material for hard coatings; however, this process is complex and not well documented in the literature. The problem lies in the difficulty of depositing thick layers of multi-component coatings with different physical characteristics, particularly the coefficient of linear thermal expansion (CLTE). As coatings undergo thermal exposure during deposition and use, different CLTEs can lead to cracking and product failure. The aim of the study is to perform on-site analysis of ZrN/CrN multilayer coatings using synchrotron radiation and investigate the micro-stress behavior of coatings deposited on a VK8 alloy substrate at temperatures up to 750°C. X-ray analysis and methods such as CLTE and qualitative determination of type II micro-stresses were used in the study. The results show changes in the characteristics of multilayer coatings during heating, the ability to determine the coefficient of thermal expansion, and qualitative determination of micro-stresses. The study provides recommendations for the application of multilayer coatings with specified characteristics. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
28. Effect of Thermal Cycling on the Structure and Phases of CrN/ZrN Multilayer Coatings Deposited by the Vacuum Arc Method.
- Author
-
Knyazhev, E. O., Vorontsov, A. V., Filippov, A. V., Shamarin, N. N., Moskvichev, E. N., Novitskaya, O. S., Denisova, Yu. A., Leonov, A. A., and Denisov, V. V.
- Abstract
Multilayer CrN/ZrN coatings deposited by the vacuum-arc method were subjected to thermal cycling in a furnace. The change in surface roughness of the coatings was studied using laser scanning confocal microscopy. Additional research was carried out using synchrotron radiation in asymmetric mode to detect the effect of thermal cycling on coating degradation. An analysis of the experimental data showed that the deposited coatings gradually degraded as the number of heating cycles increased. It should be noted that coatings obtained at substrate holder speeds of 5 and 8 rpm are more resistant to this type of impact than those obtained at speeds of 0.5 and 3.5 rpm. It is also noted that holding for 10 cycles has practically no effect on the phase state of the coatings. X-ray diffraction patterns showed the presence of β-Zr phase in the samples obtained at a substrate holder rotation speed of 5 and 8 rpm, which affected their thermal stability. However, after 40 cycles, the CoWO
4 phase was detected in the coatings, which indicates the oxidation of the substrate and the loss of the protective functions of the coatings. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
29. Phase Formation in Alkaline Titanosilicate Systems during Hydrothermal Synthesis.
- Author
-
Gerasimova, L. G., Shchukina, E. S., Maslova, M. V., and Nikolaev, A. I.
- Subjects
- *
ALKALINE hydrolysis , *TITANIUM compounds , *NEW product development , *HYDROTHERMAL synthesis , *TITANIUM - Abstract
The highly alkaline multicomponent systems TiO2–H2SO4–Na2SiO3–NaOH–H2O and TiO2–H2SO4–(NH4)2SO4–Na2SiO3–NaOH–H2O have been studied under conditions of hydrothermal synthesis, which gives new products with specified technical properties. It has been shown that, by a targeted selection of structure-forming components, in particular, titanium compounds, together with optimal parameters of hydrothermal treatment of the formed precursor, one can obtain compounds with given chemical composition and particle size and morphology. It has been found that the rate of structural transformations in the synthesis depends on the phase composition of titanosilicate precursors. Their hydrothermal treatment involves the alkaline and thermal hydrolysis followed by dehydration of the hydrolyzed phases of titanium(IV) and silicon. This is accompanied by the localization of free bonds ensuring the formation of Ti–O–Si–O bridges and their subsequent transformation into new structured species. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
30. Nucleation and growth of the Fe2AlB2 MAB phase in the combustion wave of mechanically activated Fe–Al–B reaction mixtures.
- Author
-
Potanin, A.Yu, Bashkirov, E.A., Levashov, E.A., Loginov, P.A., Berezin, M.A., and Kovalev, D.Yu
- Subjects
- *
DISCONTINUOUS precipitation , *COMBUSTION kinetics , *SELF-propagating high-temperature synthesis , *TERNARY phase diagrams , *COMBUSTION , *PHASE transitions , *MIXTURES - Abstract
This paper focuses on the effect of mechanical activation (MA) of Fe–Al–B reaction mixtures on the macrokinetic characteristics of combustion and structure formation of the synthesis products calculated for the formation of the Fe 2 AlB 2 MAB phase. Phase diagrams of the ternary system in question are constructed at different temperatures using the AFLOW and Materials Project databases. The effect of initial temperature (T 0) on the key SHS parameters is demonstrated. The combustion temperature varies within the 1110–1220 °C range; autoignition of the MA mixture occurs at T 0 > 200 °C. The impact of MA on heat release and structural phase transformations in reaction mixtures is investigated. The optimal modes of MA and SHS that allow one to synthesize a product containing up to 99% of the Fe 2 AlB 2 phase are identified. The ceramics produced in the layerwise SHS combustion mode inherit the structure of the mechanocomposite and consist of composite agglomerate particles sized up to 30 μm with grain size up to 2 μm. The stages of structural phase transformations taking place in the combustion wave during the production of the MAB phase are studied by the quenching of the combustion front and dynamic X-ray diffraction. Fe 2 AlB 2 is formed from the metallic boron-containing melt, without intermediate formation. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
31. Phase formation and hydration of alumina cements on the basis of cobalt‐molybdenum‐containing waste.
- Author
-
Logvinkov, Sergii, Korohodska, Alla, Shabanova, Halyna, and Vevadna, Svitlana
- Subjects
CEMENT ,ALUMINUM oxide ,CALCIUM aluminate ,REFRACTORY materials ,RAW materials ,PORTLAND cement ,MOLYBDENUM compounds ,SPINEL group ,COBALT - Abstract
The subject of the research is features of synthesis of alumina cements on the basis of compositions of system CaO – CoO – Al2O3 – MoO3 with use of cobalt‐molybdenum‐containing waste for reception of refractory materials with a complex of the set properties. The processes of phase formation in raw mixtures have been investigated. X‐ray phase studies of clinkers fired at different temperatures and holding times proved that as a result of the interaction of the raw materials of the mixture in the material synthesizes a mixture of hydraulically active calcium mono‐ and di‐aluminate and refractory cobalt spinel, which provides the resulting complex high strength, accelerated curing time, fire resistance. The absence of phases corresponding to molybdenum compounds is explained by the fact that they are part of hydraulically active aluminates as limited solid solutions, deforming the crystal lattice and increasing hydraulic activity. Thus, it was found that the high strength of cement is due to the presence of calcium hydroaluminates such as C2AH8, aluminum hydroxide, as well as unhydrated grains of calcium aluminates, which will contribute to further long‐term strength. It is this coexistence of phases in both the crystalline and colloidal states provide high strength cement stone. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
32. Low-Temperature Aging of Al2O3–[ZrYb]O2 Composites Containing Strontium Hexaaluminate.
- Author
-
Podzorova, L. I., Il'icheva, A. A., Pen'kova, O. I., Sirotinkin, V. P., Antonova, O. S., Baikin, A. S., and Kochanov, G. P.
- Abstract
The effect of the hydrothermal treatment corresponding to accelerated low-temperature aging and simulating a prolonged exposure to a biological environment on the phase composition and bending strength of Al
2 O3 –[ZrYb]O2 composites containing a variable amount of Al2 O3 and including strontium hexaaluminate has been investigated. It has been shown that, after the hydrothermal action, the composites retain their bending strength ranging from 700 to 850 MPa, depending on composition. This indicates the preservation of the phase composition in the bulk of the materials. It has been determined that, in the surface layer of the samples, the zirconia monoclinic phase forms in an amount from 11 to 9%, related to the growing alumina content in the composites. Such amounts of the monoclinic zirconia phase formed is well below a limit value of 25% specified by the ISO 13356 2015 standard. The investigated composites can be promising for medical applications. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
33. Body-centered cubic phase stability in cobalt-free refractory high-entropy alloys
- Author
-
Yulin Li, Łukasz Kurpaska, Eryang Lu, Zonghan Xie, Hyoung Seop Kim, and Wenyi Huo
- Subjects
Refractory high-entropy alloys ,Cobalt-free ,Phase formation ,Alloy design ,Radiation resistant ,Physics ,QC1-999 - Abstract
Cobalt-free refractory high-entropy alloys (RHEAs) are strong contenders for structural materials in nuclear reactors because they do not exhibit cobalt activity under irradiation. The mechanical properties and thermal stability of RHEAs are primarily attributed to the solid solution phase, which is essentially the body-centered cubic (BCC) phase. The BCC phase formation rules thus became the basic criterion in the compositional design of RHEAs. In this paper, the BCC phase formation rules in cobalt-free RHEAs were determined via the calculation of six semiempirical parameters, namely, the entropy of mixing, enthalpy of mixing, atomic size difference, Ω-parameter, d-orbital energy level and valance electron concentration. The mixing enthalpy and atomic size differences are more effective than other semiempirical parameters for predicting BCC phase stability in cobalt-free RHEAs. The presence of aluminum is found to cause a notable alteration in the range of phase stability in cobalt-free RHEAs.
- Published
- 2024
- Full Text
- View/download PDF
34. Phase prediction, microstructure, and mechanical properties of spark plasma sintered Ni–Al–Ti–Mn–Co–Fe–Cr high entropy alloys
- Author
-
Emmanuel Olorundaisi, Bukola J. Babalola, Moipone L. Teffo, Ufoma S. Anamu, Peter A. Olubambi, Juwon Fayomi, and Anthony O. Ogunmefun
- Subjects
Nickel aluminide ,High entropy alloy ,Phase formation ,Crystal structure ,Nanoindentation ,Microstructure ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Abstract The effect of mechanical alloying on the development of Ni–Al–Ti–Mn–Co–Fe–Cr high entropy alloys (HEAs) utilizing the spark plasma sintering (SPS) method is the main goal of this study. A bulk sample was fabricated using SPS after the alloys were mixed for 12 h. Thermodynamic simulation, X-ray diffraction, scanning electron microscopy, nanoindentation, and microhardness were used to investigate the microstructure and mechanical properties of the as-mixed powders. The master alloy was made of NiAl and was subsequently alloyed with Ti, Mn, Co, Fe, and Cr at different compositions to develop HEAs at a sintering temperature of 850 °C, a heating rate of 100 °C/min, a pressure of 50 MPa, and a dwelling time of 5 min. A uniform dispersion of the alloying material can be seen in the microstructure of the sintered HEAs with different weight elements. The grain size analysis shows that the Ni25Al25Ti8Mn8Co15Fe14Cr5 alloy exhibited a refined structure with a grain size of 2.36 ± 0.27 µm compared to a coarser grain size of 8.26 ± 0.43 μm attained by the NiAl master alloy. Similarly, the HEAs with the highest alloying content had a greater microstrain value of 0.0449 ± 0.0036, whereas the unalloyed NiAl had 0.00187 ± 0.0005. Maximum microhardness of 139 ± 0.8 HV, nanohardness of 18.8 ± 0.36 GPa, elastic modulus of 207.5 ± 1.65 GPa, elastic recovery (W e/W t) of 0.556 ± 0.035, elastic strain to failure (H/E r) of 0.09.06 ± 0.0027, yield pressure (H 3/ $$E_{{\text{r}}}^{2}$$ E r 2 ) of 0.154 ± 0.0055 GPa, and the least plasticity index (W p/W t) of 0.444 ± 0.039 were attained by Ni25Al25Ti8Mn8Co15Fe14Cr5. A steady movement to the left may be seen in the load–displacement curve. Increased resistance to indentation by the developed HEAs was made possible by the increase in alloying metals, which ultimately led to higher nanohardness and elastic modulus.
- Published
- 2023
- Full Text
- View/download PDF
35. Interaction and evolution of phases at the coating/substrate interface in galvannealed 3rd Gen AHSS with high Si content
- Author
-
Alexey Minenkov, Martin Arndt, Johannes Knapp, Günter Hesser, Christian Gierl-Mayer, Thomas Mörtlbauer, Gerhard Angeli, and Heiko Groiss
- Subjects
High-Si steel ,Hot-dip galvanizing ,Annealing ,Phase formation ,Steel-coating interface ,Materials of engineering and construction. Mechanics of materials ,TA401-492 - Abstract
Optimization of the galvannealing for cutting-edge 3rd generation AHSS requires detailed structural and chemical characterization. Alloying elements such as Si dramatically modify the steel surface, forming an oxide layer during pre-annealing, which suppresses the desired interfacial interaction. Progress is impossible without understanding the phases' interplay at the steel-coating interface. We investigated this area in high-Si (1.49 wt%) galvanized AHSS at different annealing times via TEM and revealed that while hot-dip galvanizing at 460 °C the surface oxide prevents the desired Fe-Al reaction and liquid Zn penetrating gaps in the oxide membrane forms a δ phase layer underneath. Located between the steel substrate and the oxide layer, the δ phase can grow during subsequent annealing due to incoming liquid Zn, while Fe diffusion into the coating is suppressed. The oxide film remains stable even after long-term annealing (120 s at 480 °C) separating the coating from the reaction zone. The growing δ layer interacting with the steel substrate consumes dissolved Si. Reaching a certain threshold concentration, supersaturated δ decomposes forming a δ matrix with Fe-Si-Al-based nanoprecipitates. Using EDX data, phase configuration was refined via Thermo-Calc by the Fe–Zn–Si–Al system simulation suggesting that nanoprecipitates are based on Al- and Si-rich type of α-Fe.
- Published
- 2024
- Full Text
- View/download PDF
36. The in-situ spinel formation in a magnesia alumina castable and the effect of selected additives on the properties of the castable
- Author
-
J. Angelkort, M. Cichocki, S. Higgins, Y. Lakotta-Weinhold, N. Fröse, and M. Mix
- Subjects
Spinel ,Phase formation ,Castable ,Sintering ,Additive ,Clay industries. Ceramics. Glass ,TP785-869 - Abstract
Four additives (a sodium polyphosphate, microsilica, titania and zirconia) were tested in a magnesia alumina castable to investigate their influence on the spinel formation at high temperatures. The impact of the additives is studied with respect to both the amount of spinel formed in the burned castable and the microstructure established by the spinalization.Dilatometric measurements conducted on the castables allowed to determine the onset temperature of the spinel formation, which was indicated by a strong increase of the linear thermal expansion. For phosphate-containing samples, the expansion associated with the spinelization occurred already ∼100 °C below the temperature at which the corresponding expansion was observed for the additive-free reference sample.Furthermore, by a heat-treatment of the castables at 1200 °C or 1500 °C, the phosphate-containing samples developed notably higher amounts of spinel than the reference sample. The phosphate addition in these samples also results in a remarkably larger increase of the sample volume during the heat treatment and comparatively lower mechanical strengths of the burned samples. The SiO2, TiO2, or ZrO2 additions influenced the physical properties of the castable in a substantially smaller degree than the addition of sodium phosphate, and they also exerted a smaller effect on the spinelization in the castable than the latter one.
- Published
- 2023
- Full Text
- View/download PDF
37. Mechanism and Kinetics of the Phase Formation and Dissolution of Na x WO 3 on a Pt Electrode in a Na 2 WO 4 –WO 3 Melt.
- Author
-
Kosov, Alexander V., Grishenkova, Olga V., Semerikova, Olga L., Vakarin, Sergey V., and Zaikov, Yuriy P.
- Subjects
- *
TUNGSTEN bronze , *TUNGSTEN oxides , *CHEMICAL reactions , *ELECTRODES , *MASS transfer - Abstract
A comprehensive study concerning the phase formation mechanism and growth/dissolution kinetics of sodium tungsten bronze crystals during the electrolysis of a 0.8Na2WO4–0.2WO3 melt was carried out. The regularities of deposit formation on a Pt(111) working electrode were investigated experimentally using cyclic voltammetry, chronoamperometry, scanning electron microscopy, and X-ray diffraction analysis. Models have been developed to calculate the current response during the formation, growth and dissolution of a two-phase deposit consisting of NaxWO3 and metallic tungsten or two oxide tungsten bronzes with different sodium content. These models consider mass transfer to the electrode and nuclei; chemical and electrochemical reactions with the participation of polytungstate ions, Na+, Na0, and O2−; as well as the ohmic drop effect. The approach was proposed to describe the dissolution of an NaxWO3 crystal with a nonuniform sodium distribution. The fitting of cyclic voltammograms was performed using the Levenberg–Marquardt algorithm. The NaxWO3 formation/growth/dissolution mechanism was determined. Concentration profiles and diffusion coefficients of [WnO3n]−, reaction rate constants, number density of nuclei, and time dependencies of crystal size were calculated. The proposed approaches and models can be used in other systems for the cyclic voltammogram analysis and study of the mechanism and kinetics of electrode processes complicated by phase formation; parallel and sequential electrochemical and chemical reactions; as well as the formation of a deposit characterized by a nonuniform phase and/or chemical composition. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
38. Classical to Relaxor Ferroelectric Transformation of Lanthanum Modified BaTi0.91Sn0.09O3 Ceramics.
- Author
-
Pattanakasem, Wiwat, Prasertpalichat, Sasipohn, Premwichit, Pathit, Vittayakorn, Naratip, and Bongkarn, Theerachai
- Subjects
- *
RELAXOR ferroelectrics , *LEAD-free ceramics , *LANTHANUM , *CERAMICS , *RIETVELD refinement , *HYSTERESIS loop , *X-ray diffraction , *LEAD titanate , *BARIUM titanate - Abstract
Lead-free Ba1-xLaxTi0.91Sn0.09O3 (BLTS) ceramics with x = 0, 0.01, 0.03 and 0.05, were prepared by the traditional solid-state sintering method with calcination and sintering temperatures of 1200 °C for 2 h and 1400 °C for 4 h, respectively. X-ray diffraction (XRD) measurements revealed that all the BLTS ceramics had pure perovskite structures with no detectable impurities. When x = 0 and 0.01, the ceramics exhibited coexisting orthorhombic (O) and tetragonal (T) phases, while the orthorhombic (O), tetragonal (T) and cubic phase (C) were detected in the BLTS ceramics with x = 0.03 and 0.05, which the Rietveld refinement analysis confirmed. Furthermore, increasing x in the BLTS ceramics led to a large decrease in the average grain size (from 45.7 to 0.9 µm). A significant decrease in the remnant polarization (Pr) accompanied by very slim hysteresis loops were observed for higher La (x ≥ 0.03) levels. This demonstrates that BLTS ceramics transition from classical ferroelectric to relaxor ferroelectric behavior due to changing occupancy of the A-site to La3+ from Ba2+. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
39. Phase Structure, Microstructure, and Electrical Properties of Bi0.47Na0.47Ba0.06TiO3 Ceramics with (LiNb)4+ Substituted into B-Sites.
- Author
-
Luangpangai, Anupong, Thatawong, Bhoowadol, Charoenthai, Nipaphat, Vittayakorn, Naratip, and Bongkarn, Theerachai
- Subjects
- *
MORPHOTROPIC phase boundaries , *PARTICLE size distribution , *MICROSTRUCTURE , *RIETVELD refinement , *CERAMICS - Abstract
Due to the substitution of complex ions into B-sites is very interesting in recent, lead-free Bi0.47Na0.47Ba0.06Ti1−x(LiNb)xO3 (BNBT1−xLNx) ceramics (with x = 0–0.04) were fabricated by the solid-state combustion method. The influence of (LiNb)4+ (x) on the phase structure, microstructure, and electrical properties was investigated. The X-ray diffraction (XRD) patterns exhibited a pure perovskite structure for all specimens. Coexisting rhombohedral and tetragonal phases were observed in all samples and the tetragonal phase increased with increased x, as analyzed by the Rietveld refinement method. The morphology of the BNBT1−xLNx ceramics, obtained by scanning electron microscopy (SEM), revealed almost-round grain shapes and anisotropic grain growth. The density and average grain sizes decreased from 5.84 to 5.54 g/cm3 and 1.7 to 0.9 µm, respectively, when x increased from 0 to 0.04. The grain size distribution decreased with increased (LiNb)4+ content. A reduction in the dielectric properties was observed, due to the phase ratio changing away from a morphotropic phase boundary (MPB), an inferior microstructure, and low density caused by (LiNb)4+ substitution. The (LiNb)4+ substitution induced the transition from non-ergodic relaxor to ergodic relaxor ferroelectric state. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
40. Alternative Local Melting‐Solidification of Suspended Nanoparticles for Heterostructure Formation Enabled by Pulsed Laser Irradiation.
- Author
-
Shakeri, Mohammad Sadegh, Swiatkowska‐Warkocka, Zaneta, Polit, Oliwia, Itina, Tatiana, Maximenko, Alexey, Depciuch, Joanna, Gurgul, Jacek, Mitura‐Nowak, Marzena, Perzanowski, Marcin, Dziedzic, Andrzej, and Nęcki, Jarosław
- Subjects
- *
PULSED lasers , *MOLECULAR force constants , *COPPER catalysts , *AB-initio calculations , *ETHANOL as fuel , *CHEMICAL reactions , *IRRADIATION - Abstract
Phase formation by pulsed laser irradiation of suspended nanoparticles has recently been introduced as a promising synthesis technique for heterostructures. The main challenge still lingers regarding the exact mechanism of particle formation due to the non‐equilibrium kinetic by‐products resulting from the localized alternative, fast, high‐temperature nature of the process. Here, the authors analyze the bond breaking/formation of copper or copper (II) interfaces with ethanol during the absorption of pulses for Cu‐CuO‐Cu2O formation applicable as an electrocatalyst in ethanol oxidation fuel cells. This study includes but is not limited to, a comprehensive discussion of the interaction between nano‐laser pulses and suspension for practical control of the synthesis process. The observed exponential and logarithmic changes in the content of heterostructures for the CuO‐ethanol and Cu‐ethanol samples irradiated with different fluences are interpreted as the dominant role of physical and chemical reactions, respectively, during the pulsed laser irradiation of suspensions synthesis. It is also shown that the local interface between dissociated ethanol and the molten sphere is responsible for the oxidative/reductive interactions resulting in the formation of catalytic‐augmented Cu3+ by‐product, thanks to the reactive bond force field molecular dynamics studies confirmed by ab‐initio calculations and experimental observations. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
41. Phase prediction, microstructure, and mechanical properties of spark plasma sintered Ni–Al–Ti–Mn–Co–Fe–Cr high entropy alloys.
- Author
-
Olorundaisi, Emmanuel, Babalola, Bukola J., Teffo, Moipone L., Anamu, Ufoma S., Olubambi, Peter A., Fayomi, Juwon, and Ogunmefun, Anthony O.
- Subjects
MICROSTRUCTURE ,MECHANICAL alloying ,IRON-manganese alloys ,ALLOYS ,ENTROPY ,ELASTIC modulus ,SCANNING electron microscopy ,ALLOY powders - Abstract
The effect of mechanical alloying on the development of Ni–Al–Ti–Mn–Co–Fe–Cr high entropy alloys (HEAs) utilizing the spark plasma sintering (SPS) method is the main goal of this study. A bulk sample was fabricated using SPS after the alloys were mixed for 12 h. Thermodynamic simulation, X-ray diffraction, scanning electron microscopy, nanoindentation, and microhardness were used to investigate the microstructure and mechanical properties of the as-mixed powders. The master alloy was made of NiAl and was subsequently alloyed with Ti, Mn, Co, Fe, and Cr at different compositions to develop HEAs at a sintering temperature of 850 °C, a heating rate of 100 °C/min, a pressure of 50 MPa, and a dwelling time of 5 min. A uniform dispersion of the alloying material can be seen in the microstructure of the sintered HEAs with different weight elements. The grain size analysis shows that the Ni
25 Al25 Ti8 Mn8 Co15 Fe14 Cr5 alloy exhibited a refined structure with a grain size of 2.36 ± 0.27 µm compared to a coarser grain size of 8.26 ± 0.43 μm attained by the NiAl master alloy. Similarly, the HEAs with the highest alloying content had a greater microstrain value of 0.0449 ± 0.0036, whereas the unalloyed NiAl had 0.00187 ± 0.0005. Maximum microhardness of 139 ± 0.8 HV, nanohardness of 18.8 ± 0.36 GPa, elastic modulus of 207.5 ± 1.65 GPa, elastic recovery (We /Wt ) of 0.556 ± 0.035, elastic strain to failure (H/Er ) of 0.09.06 ± 0.0027, yield pressure (H3 / E r 2 ) of 0.154 ± 0.0055 GPa, and the least plasticity index (Wp /Wt ) of 0.444 ± 0.039 were attained by Ni25 Al25 Ti8 Mn8 Co15 Fe14 Cr5 . A steady movement to the left may be seen in the load–displacement curve. Increased resistance to indentation by the developed HEAs was made possible by the increase in alloying metals, which ultimately led to higher nanohardness and elastic modulus. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
42. Effects of Alloying Elements and Mechanical Alloying on Characteristics of WVTaTiCr Refractory High-Entropy Alloys.
- Author
-
Chen, Chun-Liang and Lin, Jyun-Hong
- Subjects
- *
MECHANICAL alloying , *LAVES phases (Metallurgy) , *ALLOYS , *CONSTRUCTION materials , *TANTALUM , *DISPERSION strengthening , *NUCLEAR energy - Abstract
Refractory high-entropy alloys (RHEAs) are among the promising candidates for the design of structural materials in advanced nuclear energy systems. The effects of Cr, V, Ta, and Ti elements and ball milling on the microstructural evolution and mechanical properties of model RHEAs were investigated. The results show that W-rich BCC1 and Ta-rich BCC2 solid solution phases were generated after a long milling duration. After high-temperature sintering, the (Cr, Ta)-rich phase associated with the Laves phase was observed in the Cr-containing model RHEAs. In addition, a high level of Ti, Ta, and V contents promoted the in situ formation of oxide particles in the alloys. Complex TiTa2O7 and Ta2VO6 oxide phases were identified by TEM, which suggests a solid-state reaction of Ti-O, Ta-O, and V-O subjected to high-energy ball milling. The oxide particles are uniformly dispersed in the BCC matrix, which can result in dispersion strengthening and the enhancement of mechanical properties. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
43. Features of Ceramic Material Formation Based Upon Cobalt (II) Ferrite.
- Author
-
Shabel'skaya, N. P., Radzhabov, A. M., Gaidukova, Yu. A., and Arzumanova, A. V.
- Subjects
- *
FERRITES , *COBALT , *CERAMIC materials , *CERAMICS , *HYDROGEN peroxide , *ORGANIC dyes , *CATALYTIC activity , *NICKEL ferrite - Abstract
Results of studying features of spinel structure formation in the CoO–Fe2O3 system obtained using various production techniques are presented. The possibility of forming cobalt (II) ferrite at the surface of a number of carriers is considered. It is shown that depending upon structural characteristics of the substrate, the cobalt (II) ferrite formed has different dispersion and degree of reversibility. It is established that increased catalytic activity in the process of purification of an aqueous solution from an organic dye during hydrogen peroxide breakdown of synthesized materials with an organic carrier has been established. [ABSTRACT FROM AUTHOR]
- Published
- 2023
- Full Text
- View/download PDF
44. The Effect of Operational Factors on Phase Formation Patterns in the Light-Water Reactor Pressure Vessel Steels.
- Author
-
Fedotova, Svetlana and Kuleshova, Evgenia
- Subjects
NEUTRON irradiation ,PRESSURE vessels ,ATOM-probe tomography ,THERMAL resistance ,STEEL ,COPPER ,POINT defects - Abstract
This paper presents the results of atom probe tomography studies on radiation-induced phase formation in light-water reactor pressure vessel steels after neutron irradiation under various conditions in comparison with the literature data. The given irradiation conditions are fluence (10–100) × 10
22 m−2 , flux (5–2700) × 1014 m−2 s−1 and irradiation temperature (50–400) °C. The composition of the studied steels varies in a wide range for the elements significantly affecting radiation and thermal resistance of steels: Ni in the range of 0.2–6.0 wt.%, Mn–0.03–1.1 wt.%, Cu–0.01–0.16 wt.%, and P–0.01–0.03 wt.%. The number density, volume fraction, size, composition, and nucleation sites of precipitates are determined. The regularities of the effect of various operational factors on the phase formation in these steels have been analyzed and revealed. The study shows that in materials with high copper content, Cu-rich precipitates are formed by a radiation-enhanced mechanism. In materials with low copper content, their formation upon irradiation at 300 °C occurs by a radiation-induced mechanism since the main nucleation sites are point defect clusters formed in cascades. At the same time, the density, volume fraction, and composition of the precipitates depend on the steel composition (Ni and Mn content). In the steel with increased Ni content up to 5 wt.% but with ultra-low Mn content ≤ 0.03 wt.%, it is possible to suppress the formation of Ni-Si-Mn precipitates under irradiation. [ABSTRACT FROM AUTHOR]- Published
- 2023
- Full Text
- View/download PDF
45. Microstructural Evolution and Magnetocaloric Properties of Cold Plastically Deformed LaFe10.9Co0.7Si1.4 Compound
- Author
-
Chen, RuZhao, Fu, Bin, Han, Jie, and Hu, Jie
- Published
- 2024
- Full Text
- View/download PDF
46. Magnetic properties, structural investigation and optical studies of Er3+doping Cd-Mg spinel ferrite
- Author
-
Venu, S., Prasad, N. V. Krishna, Kumar, N. Hari, ChandrababuNaidu, K., Vinod, G., and Ravinder, D.
- Published
- 2024
- Full Text
- View/download PDF
47. SYNTHESIS OF HIGH BELITE SULFOALUMINATE CEMENT CONTAINING MAGNESIA-ALUMINA SPINEL WITH SOLID WASTE
- Author
-
Liang Yu, Jie Zhang, Wang Zengyao, Yan Jinghua, Wang Shoude, Zhao Piqi, and Cheng Xin
- Subjects
belite sulfoaluminate cement ,high magnesium limestone ,solid waste ,phase formation ,Clay industries. Ceramics. Glass ,TP785-869 - Abstract
A high belite sulfoaluminate cement clinker containing a magnesia-alumina spinel was prepared using industrial solid waste and high-magnesium limestone. The preparation procedure and the influence of the trace elements on the clinker were specifically investigated. This study reveals the mechanism of the clinker formation. The appropriate firing temperature of the clinker and holding time were determined to be 1300 °C and 60 min - 90 min, respectively. The presence of MgO and SO₃ displayed a positive effect on the clinker formation at high temperatures. In addition, the excessive MgO in the raw material was solidified to create the stable inertia mineral MgAl₂O₄, which eliminated the delaying expansion hazard of MgO.
- Published
- 2023
- Full Text
- View/download PDF
48. High temperature oxidation behavior of Fe–3.0%Si steel with non-equilibrium reaction
- Author
-
E. Ma, Xingrui Yang, Yingtao Su, Zimo Bi, Huilan Sun, Bo Wang, Cheng Ma, and Di Zhang
- Subjects
Oxidation mechanism ,Fe–3.0%Si steel ,Microstructure evolution ,Phase formation ,Oxide layer morphology ,Mining engineering. Metallurgy ,TN1-997 - Abstract
The phase formation-transition process and microstructure evolution of Fe–3%Si steel oxide layers were systematically studied during the high-temperature oxidation process with oxidizing atmosphere when annealed at 1000–1240 °C for 200 min. The micromorphology, oxidation mechanism and crystal structure stability were characterized and discussed combining with the XRD, FESEM and XPS technology. The oxidized scale shows more and more complex multiple layers structure including single layer, double layers and three layers with the increasing of annealing temperature, which attributes to the diffusion effect and oxidation reaction oxygen anions and metal cations. The formation of SiO2, FeO and Fe2SiO4 layer also could inhibit the oxidation reaction of matrix. The oxidized scale mainly shows a single layer structure of Fe2O3 when annealed at 1000–1080 °C, which is easy to peel off from matrix. It shows a double oxide layers structure when annealed at 1080–1120 °C, the loose outer layer contains Fe2O3, and the grid inner layer contain SiO2, FeO and Fe2SiO4 compounds. It shows an outermost, intermediate and inner three layers structure when annealed at 1160–1240 °C. The outermost layer is Fe2O3, the main phases of intermediate layer are FeO and Fe2SiO4 compounds as well as some SiO2 particles, and the inner layer (joint layer) is SiO2.
- Published
- 2023
- Full Text
- View/download PDF
49. Towards a Sustainable Laser Powder Bed Fusion Process via the Characterisation of Additively Manufactured Nitinol Parts
- Author
-
Muhannad Ahmed Obeidi, Paul Healy, Hasan Alobaidi, Declan Bourke, and Dermot Brabazon
- Subjects
sustainability ,additive manufacturing ,laser powder bed fusion ,nitinol ,3D printing ,phase formation ,Technology ,Engineering design ,TA174 - Abstract
Is additive manufacturing (AM) a sustainable process? Can the process be optimised to produce sustainable AM parts and production techniques? Additive manufacturing offers the production of parts made of different types of materials in addition to the complex geometry that is difficult or impossible to produce by using the traditional subtractive methods. This study is focused on the optimisation of laser powder bed fusion (L-PBF), one of the most common technologies used in additive manufacturing and 3D printing. This research was carried out by modulating the build layer thickness of the deposited metal powder and the input volumetric energy density. The aim of the proposed strategy is to save the build time by maximizing the applied layer thickness of nitinol powder while retrieving the different AM part properties. The saving in the process time has a direct effect on the total cost of the produced part as a result of several components like electric energy, inert gas consumption, and labour. Nickel-rich nitinol (52.39 Ni at.%) was selected for investigation in this study due to its extremely high superplastic and shape memory properties in addition to the wide application in various industries like aerospace, biomedical, and automotive. The results obtained show that significant energy and material consumption can be found by producing near full dens AM parts with limited or no alteration in chemical and mechanical properties.
- Published
- 2024
- Full Text
- View/download PDF
50. Characterization of Mn5Ge3 Contacts on a Shallow Ge/SiGe Heterostructure
- Author
-
Troy A. Hutchins-Delgado, Sadhvikas J. Addamane, Ping Lu, and Tzu-Ming Lu
- Subjects
Mn5Ge3 ,Ge/SiGe ,thin film ,germanide ,phase formation ,solid-state synthesis ,Chemistry ,QD1-999 - Abstract
Mn5Ge3 is a ferromagnetic phase of the Mn-Ge system that is a potential contact material for efficient spin injection and detection. Here, we investigate the creation of Mn5Ge3-based contacts on a Ge/SiGe quantum well heterostructure via solid-state synthesis. X-ray diffraction spectra fitting indicates the formation of Mn5Ge3-based contacts on bulk Ge and Ge/SiGe. High-resolution scanning transmission electron microscopy imaging and energy dispersive X-ray spectroscopy verify the correct Mn5Ge3-based phase formation. Schottky diode measurements, transmission line measurements, and Hall measurements reveal that Mn5Ge3-based contacts serve as good p-type contacts for Ge/SiGe quantum well heterostructures due to having a low Schottky barrier height of 0.10eV (extracted from a Mn5Ge3/n-Ge analogue) and a contact resistance in the order of 1 kΩ. Furthermore, we show that these electrical characteristics have a gate-voltage dependence, thereby providing tunability.
- Published
- 2024
- Full Text
- View/download PDF
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.