Phase constitution of the noble metal thin-film complex solid solution system Ag-Ir-Pd-Pt-Ru in dependence of elemental compositions and annealing temperatures

AbstractMultiple-principal element alloys hold great promise for multifunctional material discovery (e.g., for novel electrocatalysts based on complex solid solutions) in a virtually unlimited compositional space. Here, the phase constitution of the noble metal system Ag-Ir-Pd-Pt-Ru was investigated over a large compositional range in the quinary composition space and for different annealing temperatures from 600 to 900 °C using thin-film materials libraries. Composition-dependent X-ray diffraction mapping of the as-deposited thin-film materials library indicates different phases being present across the composition space (face-centered cubic (fcc), hexagonal close packed (hcp) and mixed fcc + hcp), which are strongly dependent on the Ru content. In general, low Ru contents promote the fcc phase, whereas high Ru contents favor the formation of an hcp solid-solution phase. Furthermore, a temperature-induced phase transformation study was carried out for a selected measurement area of fcc-Ag5Ir8Pd56Pt8Ru23. With increasing temperature, the initial fcc phase transforms to an intermediate C14-type Laves phase at 360 °C, and then to hcp when the temperature reaches 510 °C. The formation and disappearance of the hexagonal Laves phase, which covers a wide temperature range, plays a crucial role of bridging the fcc to hcp phase transition. The obtained composition, phase and temperature data are transformed into phase maps which could be used to guide theoretical studies and lay a basis for tuning the functional properties of these materials.

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An In-situ Electron Microscopy Study of Microstructural Evolution in a Co-NbCo2 Binary Alloy

MRS Proceedings ◽

10.1557/proc-1128-u08-09 ◽

2008 ◽

Vol 1128 ◽

Author(s):

Sharvan Kumar ◽

Padam Jain ◽

Seong Woong Kim ◽

Frank Stein ◽

Martin Palm

Keyword(s):

Electron Microscopy ◽

Solid Solution ◽

Microscopy Study ◽

Electron Microscopy Study ◽

Laves Phase ◽

Face Centered Cubic ◽

The Matrix ◽

The Individual ◽

Individual Grains

AbstractThe microstructure in a Co-rich, Co-15 at.% Nb alloy was characterized in the as-cast condition. A predominantly lamellar eutectic morphology composed of a Co-Nb solid solution and the C15 Laves phase NbCo2 was confirmed by transmission electron microscopy. The C15 phase was heavily twinned, with only one variant of twins being present in the individual lamella, while the Co solid solution had the face centered cubic structure. In-situ heating to 600°C in the microscope confirmed the decomposition of the metastable Laves phase into a fine equiaxed, ˜10-20 nm grain size microstructure, and the product phase is the monoclinic Nb2Co7. The individual grains appear faulted. The matrix solid solution retained the fcc structure and no change in structure was observed on cooling to room temperature. Heating to temperatures as high as 1130°C leads to rapid grain growth in the Nb2Co7 phase, and the nucleation and growth of a few new grains within the original grains; however, the reverse peritectoid transformation previously reported, was not observed.

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Synthesis of Au or Pt@Perovskite Nanocrystals via Interfacial Photoreduction

Catalysts ◽

10.3390/catal11020174 ◽

2021 ◽

Vol 11 (2) ◽

pp. 174

Author(s):

Jing Zhang ◽

Li Wang ◽

Wenwen Liu ◽

Mengsha Cao ◽

Jing Zhang ◽

...

Keyword(s):

Noble Metal ◽

Noble Metals ◽

Perovskite Phase ◽

Pt Nanoparticles ◽

Noble Metal Nanoparticles ◽

Great Promise ◽

Face Centered Cubic ◽

Time Resolved ◽

Perovskite Nanocrystals ◽

Average Size

The surface modification of perovskite nanocrystals (NCs) (i.e., their decoration with noble metals) holds great promise with respect to the tailoring of their properties but has remained a challenge because perovskite NCs are extremely sensitive to water and alcohols. In this study, Au or Pt@CsPbBr3 NCs were successfully synthesized by photoreduction at the water/hexane interface. First, Cs4PbBr6 NCs were synthesized through the hot-injection method. Then, Cs4PbBr6 was transformed into CsPbBr3 and subjected to noble metal modification, both at the interface. The synthesized CsPbBr3 NCs exhibited a cubic perovskite phase and had an average size of approximately 13.5 nm. The deposited Au and Pt nanoparticles were crystalline, with a face-centered cubic lattice and average diameters of approximately 3.9 and 4.4 nm, respectively. The noble metal modification process had almost no effect on the steady-state photoluminescence (PL) emission wavelength but affected the charge-recombination kinetics of the CsPbBr3 NCs. Time-resolved PL decay spectral analysis indicated that the fluorescence lifetimes of the Au and Pt@CsPbBr3 NCs were shorter than those of the pure CsPbBr3 NCs, probably owing to the quenching of the free charges because of electron transfer from the perovskite to the noble metal nanoparticles.

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Electron diffraction detection of ordliking in annealed PbTe thin film

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100178227 ◽

1990 ◽

Vol 48 (4) ◽

pp. 1018-1019

Author(s):

Karimat El-Sayed

Keyword(s):

Thin Film ◽

Electron Diffraction ◽

Lead Telluride ◽

Structural Basis ◽

Face Centered Cubic ◽

X Ray ◽

Polycrystalline Thin Films ◽

Stage Process ◽

Diffraction Patterns ◽

Face Centered

Lead telluride is an important semiconductor of many applications. Many Investigators showed that there are anamolous descripancies in most of the electrophysical properties of PbTe polycrystalline thin films on annealing. X-Ray and electron diffraction studies are being undertaken in the present work in order to explain the cause of this anamolous behaviour.Figures 1-3 show the electron diffraction of the unheated, heated in air at 100°C and heated in air at 250°C respectively of a 300°A polycrystalline PbTe thin film. It can be seen that Fig. 1 is a typical [100] projection of a face centered cubic with unmixed (hkl) indices. Fig. 2 shows the appearance of faint superlattice reflections having mixed (hkl) indices. Fig. 3 shows the disappearance of thf superlattice reflections and the appearance of polycrystalline PbO phase superimposed on the [l00] PbTe diffraction patterns. The mechanism of this three stage process can be explained on structural basis as follows :

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Nanoporous Quasi-High-Entropy Alloy Microspheres

Metals ◽

10.3390/met9030345 ◽

2019 ◽

Vol 9 (3) ◽

pp. 345 ◽

Cited By ~ 3

Author(s):

Lianzan Yang ◽

Yongyan Li ◽

Zhifeng Wang ◽

Weimin Zhao ◽

Chunling Qin

Keyword(s):

Mechanical Properties ◽

Solid Solution ◽

Specific Surface ◽

Surface Area ◽

Specific Surface Area ◽

High Specific Surface Area ◽

High Entropy Alloy ◽

Face Centered Cubic ◽

High Entropy ◽

Hierarchical Porous

High-entropy alloys (HEAs) present excellent mechanical properties. However, the exploitation of chemical properties of HEAs is far less than that of mechanical properties, which is mainly limited by the low specific surface area of HEAs synthesized by traditional methods. Thus, it is vital to develop new routes to fabricate HEAs with novel three-dimensional structures and a high specific surface area. Herein, we develop a facile approach to fabricate nanoporous noble metal quasi-HEA microspheres by melt-spinning and dealloying. The as-obtained nanoporous Cu30Au23Pt22Pd25 quasi-HEA microspheres present a hierarchical porous structure with a high specific surface area of 69.5 m2/g and a multiphase approximatively componential solid solution characteristic with a broad single-group face-centered cubic XRD pattern, which is different from the traditional single-phase or two-phase solid solution HEAs. To differentiate, these are named quasi-HEAs. The synthetic strategy proposed in this paper opens the door for the synthesis of porous quasi-HEAs related materials, and is expected to promote further applications of quasi-HEAs in various chemical fields.

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Stability and equation of state of face-centered cubic and hexagonal close packed phases of argon under pressure

Scientific Reports ◽

10.1038/s41598-021-93995-y ◽

2021 ◽

Vol 11 (1) ◽

Author(s):

Agnès Dewaele ◽

Angelika D. Rosa ◽

Nicolas Guignot ◽

Denis Andrault ◽

João Elias F. S. Rodrigues ◽

...

Keyword(s):

Equation Of State ◽

Single Crystal ◽

Single Crystal Sample ◽

Moderate Pressure ◽

Face Centered Cubic ◽

Experimental Conditions ◽

Crystal Sample ◽

Hexagonal Close Packed ◽

Face Centered ◽

Fcc Phase

AbstractThe compression of argon is measured between 10 K and 296 K up to 20 GPa and and up to 114 GPa at 296 K in diamond anvil cells. Three samples conditioning are used: (1) single crystal sample directly compressed between the anvils, (2) powder sample directly compressed between the anvils, (3) single crystal sample compressed in a pressure medium. A partial transformation of the face-centered cubic (fcc) phase to a hexagonal close-packed (hcp) structure is observed above 4.2–13 GPa. Hcp phase forms through stacking faults in fcc-Ar and its amount depends on pressurizing conditions and starting fcc-Ar microstructure. The quasi-hydrostatic equation of state of the fcc phase is well described by a quasi-harmonic Mie–Grüneisen–Debye formalism, with the following 0 K parameters for Rydberg-Vinet equation: $$V_0$$ V 0 = 38.0 Å$$^3$$ 3 /at, $$K_0$$ K 0 = 2.65 GPa, $$K'_0$$ K 0 ′ = 7.423. Under the current experimental conditions, non-hydrostaticity affects measured P–V points mostly at moderate pressure ($$\le$$ ≤ 20 GPa).

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Performance Improvement of ZnSnO Thin-Film Transistors with Low-Temperature Self-Combustion Reaction

Electronics ◽

10.3390/electronics10091099 ◽

2021 ◽

Vol 10 (9) ◽

pp. 1099

Author(s):

Ye-Ji Han ◽

Se Hyeong Lee ◽

So-Young Bak ◽

Tae-Hee Han ◽

Sangwoo Kim ◽

...

Keyword(s):

Thin Film ◽

Photoelectron Spectroscopy ◽

Large Scale ◽

Low Cost ◽

Thermal Analyses ◽

Thin Film Transistor ◽

Sol Gel ◽

Annealing Temperatures ◽

Zinc Tin Oxide ◽

Thermal Limitation

Conventional sol-gel solutions have received significant attention in thin-film transistor (TFT) manufacturing because of their advantages such as simple processing, large-scale applicability, and low cost. However, conventional sol-gel processed zinc tin oxide (ZTO) TFTs have a thermal limitation in that they require high annealing temperatures of more than 500 °C, which are incompatible with most flexible plastic substrates. In this study, to overcome the thermal limitation of conventional sol-gel processed ZTO TFTs, we demonstrated a ZTO TFT that was fabricated at low annealing temperatures of 350 °C using self-combustion. The optimized device exhibited satisfactory performance, with μsat of 4.72 cm2/V∙s, Vth of −1.28 V, SS of 0.86 V/decade, and ION/OFF of 1.70 × 106 at a low annealing temperature of 350 °C for one hour. To compare a conventional sol-gel processed ZTO TFT with the optimized device, thermogravimetric and differential thermal analyses (TG-DTA) and X-ray photoelectron spectroscopy (XPS) were implemented.

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Sputter Deposition of Fe-Co Nitride for Ferromagnetic Granular Nitride Thin Film

Materials Science Forum ◽

10.4028/www.scientific.net/msf.631-632.327 ◽

2009 ◽

Vol 631-632 ◽

pp. 327-331 ◽

Cited By ~ 1

Author(s):

K. Sakon ◽

Y. Hirokawa ◽

Yasuji Masubuchi ◽

Shinichi Kikkawa

Keyword(s):

Thin Film ◽

Solid Solution ◽

Thermal Decomposition ◽

Sputter Deposition ◽

Composite Target ◽

Zinc Blende ◽

Alloy Particles ◽

Sputter Deposited ◽

Magneto Resistance ◽

Zinc Blende Structure

Sputter deposited Fe0.7Co0.3 nitride thin film had zinc blende structure. It was thermally decomposed completely back to the ferromagnetic Fe0.7Co0.3 alloy above 400°C. As-deposited nitride thin films obtained in cosputtering of (Fe0.7Co0.3)1-xAlx composite target with nitrogen sputter gas were solid solutions with zinc blende (x≤0.44) and wurtzite (x>0.5) type structure, respectively. The largest magneto resistance ratio of 0.24% was observed on the Fe0.7Co0.3 alloy particles dispersed in AlN thin film obtained by thermal decomposition of the nitride solid solution with x=0.66 at 500°C.

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Effects of Annealing Temperature on Morphology and Dielectric Property of BiFeO3 Films

Key Engineering Materials ◽

10.4028/www.scientific.net/kem.512-515.1736 ◽

2012 ◽

Vol 512-515 ◽

pp. 1736-1739

Author(s):

Li Li Zhang ◽

Guo Qiang Tan ◽

Meng Cheng ◽

Hui Jun Ren ◽

Ao Xia

Keyword(s):

Thin Film ◽

Thin Films ◽

Dielectric Property ◽

Annealing Temperature ◽

Raw Materials ◽

Sol Gel ◽

Frequency Range ◽

Annealing Temperatures ◽

Pure Phase ◽

Lower Loss

Fe(NO3)3•9H2O and Bi(NO3)3•5H2O were used as raw materials. BiFeO3 thin films were prepared by sol-gel method. The effects of annealing temperatures on the morphology and dielectric property of the thin films were studied. XRD results show that the multi-crystal thin films with pure phase are obtained when annealed at 500°C and 550°C. But annealing at 580°C will lead to the appearance of Bi2.46Fe5O12 phase.AFM images show that as the increase of annealing temperatures the surface toughness of the thin film is decreased, but the surface undulation of the thin films is decreased gradually. Within the frequency range of 1KHz~1MHz, the dielectric constant of BiFeO3 thin films is kept over 125 and it does not change very much from 500°C to 580°C. Annealed at 550°C, the BiFeO3 thin films with the lower loss are obtained. At 1MHz, the dielectric loss is 0.12.

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