scholarly journals Structure Formation and Corrosion Behaviour of Quasicrystalline Al–Ni–Fe Alloys

2017 ◽  
Vol 18 (2) ◽  
pp. 222-227 ◽  
Author(s):  
О.V. Sukhova ◽  
V.A. Polonskyy ◽  
К.V. Ustinovа
Keyword(s):  
Room Temperature ◽  
Volume Fraction ◽  
Corrosion Behaviour ◽  
Corrosion Performance ◽  
X Ray Diffraction ◽  
X Ray ◽  
Acidic Solutions ◽  
Decagonal Phase ◽  
Fe Alloys ◽  
Saline Solutions

The formation of quasicrystalline decagonal phase and related crystalline phases was investigated by a combination of optical metallography, powder X-ray diffraction, atomic absorption spectroscopy and differential thermal analysis. Corrosion behaviour of quasicrystal Al–Ni–Fe alloys was studied by gravimetric and potentiodynamic polarization experiments in saline and acidic solutions at room temperature. The decagonal phase exhibits two modifications (AlFe- and AlNi-based) depending on the composition. In Al72Ni13Fe15 alloy it coexists with monoclinic Al5FeNi phase. In Al71.6Ni23Fe5.4 alloy crystalline Al13(Ni,Fe)4, Al3(Ni,Fe)2, and Al3(Ni,Fe) phases are seen adjacent to the quasicrystalline decagonal phase. Stability of quasicrystal phase up to room temperature was shown to be connected with its incomplete decomposition during cooling at a rate of 50 K/min. Al72Ni13Fe15 alloy has more than twice larger volume fraction of this phase compared to that of Al71.6Ni23Fe5.4 alloy. A dependence of microhardness on composition was observed as well, with Al72Ni13Fe15 alloy having substantially higher values. In acidic solutions, Al71.6Ni23Fe5.4 alloy showed the best corrosion performance. In saline solutions, the investigated alloys remained mainly untouched by corrosion. Mass-change kinetics exhibited parabolic growth rate. 

Spark Plasma Sintering of Ti-4.5Al-3V-2Fe-2Mo (SP-700)

2010 ◽  
Vol 654-656 ◽  
pp. 819-822
Author(s):  
Genki Kikuchi ◽  
Hiroshi Izui ◽  
Yuya Takahashi ◽  
Shota Fujino
Keyword(s):  
Spark Plasma Sintering ◽  
Room Temperature ◽  
Volume Fraction ◽  
Titanium Boride ◽  
Tensile Tests ◽  
X Ray Diffraction ◽  
X Ray ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
Tib2 Particles

In this study, we focused on the sintering performance of Ti-4.5Al-3V-2Mo-2Fe (SP-700) and mechanical properties of SP-700 reinforced with titanium boride (TiB/SP-700) fabricated by spark plasma sintering (SPS). TiB whiskers formed in titanium by a solid-state reaction of titanium and TiB2 particles were analyzed with scanning electron microscopy and X-ray diffraction. The TiB/SP-700 was sintered at temperatures of 1073, 1173, and 1273 K and a pressure of 70 MPa for 10, 30, and 50 min. The volume fraction of TiB ranged from 1.7 vol.% to 19.9 vol.%. Tensile tests of TiB/SP-700 were conducted at room temperature, and the effect of TiB volume fraction on the tensile properties was investigated.

Zn-TiO2 and ZnNi-TiO2 Nanocomposite Coatings: Corrosion Behaviour

2010 ◽  
Vol 636-637 ◽  
pp. 1079-1083 ◽  
Author(s):  
Augusto Gomes ◽  
I. Almeida ◽  
Tania Frade ◽  
Ana C. Tavares
Keyword(s):  
Room Temperature ◽  
Corrosion Potential ◽  
Corrosion Behaviour ◽  
Pulse Method ◽  
Nanocomposite Coating ◽  
Nanocomposite Coatings ◽  
Tio2 Films ◽  
X Ray Diffraction ◽  
X Ray ◽  
Steel Electrodes

This work presents the corrosion behaviour of the as-prepared of Zn-TiO2 and ZnNi-TiO2 films in neutral Na2SO4 solution and a first attempt to correlate with their composition, morphology and structure. The films were prepared by galvanostatic pulse method onto steel electrodes, at room temperature. The X-ray diffraction study revealed that the ZnNi alloy consists of a homogenous Ni5Zn21 phase and that the preferred crystallographic orientation of Zn deposits changes in the presence of TiO2. The SEM results show that the morphology of the metallic coating is function of the metal phase composition and become more porous in the presence of 1.5 wt% TiO2.The corrosion parameters for the nanocomposite coatings were compared with those of pure Zn and ZnNi electrodeposits, and the ZnNi-TiO2 nanocomposite coating shows the less cathodic corrosion potential.

Effect of titanium addition on a Ni-Al-Co alloy

1990 ◽  
Vol 48 (4) ◽  
pp. 938-939
Author(s):  
L. S. Lin ◽  
G. W. Levan ◽  
S. M. Russell ◽  
C. C. Law
Keyword(s):  
Grain Size ◽  
Grain Boundaries ◽  
Room Temperature ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Titanium Addition ◽  
X Ray ◽  
Gamma Prime ◽  
Room Temperature Ductility ◽  
Ti Addition

AEM examinations of a NiAlCo alloy of composition Ni-29 at.% Al-21 at.% Co after room temperature compression show that the microstructure consists of a twinned tetragonal matrix (L10, marked A in Figure 1a) and ordered fcc gamma prime precipitates (L12, marked B in Figure 1a) along grain boundaries. The compressive yield strengths of this alloy at room temperature and 760°C are 754 MPa and 163 MPa respectively. It also has superior room temperature ductility as compared to binary NiAl. An addition of 5 at.% Ti at the expense of Ni was made to this alloy in order to increase the yield strengths. The quarternary alloy shows compressive yield strengths of 976 MPa and 403 MPa at room temperature and 760°C, respectively, indicating that the Ti addition is having the desired effect.Comparison of the microstructures of the two alloys after room temperature compression (Figures la and lb) shows that the Ti containing alloy has a smaller grain size. X-ray diffraction data indicate that the gamma prime volume fraction increases from 10% to 20% as the result of the Ti addition. Titanium was also found to stabilize the B2 matrix (marked A in Figure lb) as no tetragonal L10 phase was found. All precipitates along grain boundaries were identified by micro-diffraction to be gamma prime.

Ultra-Thin Al2O3 Formation at Room Temperature

2010 ◽  
Vol 93-94 ◽  
pp. 113-116
Author(s):  
Puenisara Limnonthakul ◽  
Artorn Pokaipisit ◽  
Pichet Limsuwan
Keyword(s):  
Crystal Structure ◽  
Silicon Wafer ◽  
Room Temperature ◽  
Volume Fraction ◽  
Effective Medium Approximation ◽  
X Ray Diffraction ◽  
Dc Magnetron Sputtering ◽  
X Ray ◽  
Transmission Electron ◽  
Sputtering Power

Ultra-thin Al films were deposited with different deposition times on silicon wafer and copper grid by dc magnetron sputtering. The sputtering power of 200 watt and Ar flow rate of 20 sccm were used to prepare the films. The deposition times were 40, 120 and 240 second, respectively. The deposited Al films were, then, left in the air under the humidity of 60% for 20 days. The crystal structure of ultra-thin Al films deposited on silicon wafer and copper grid were investigated by glazing x-ray diffraction (GXRD) and transmission electron microscopy (TEM), respectively. The XRD results show that after the ultra thin Al films were exposed to the air, the Al was oxidized and the Al2O3 was formed at room temperature. In addition, Al deposited for 120 and 240 second can form polycrystalline of -Al2O3 with preferred orientations of (110) and (311) planes. The TEM images show that the particle size of -Al2O3 was about 8.5 nm for deposited time of 120 second. Moreover, the spectroscopic ellipsometry (SE) data and simulation model of Bruggemann effective medium approximation (BEMA) was used to determine the volume fraction of Al2O3.

An In Situ High-Temperature X-Ray Diffraction Study of Phase Transformations in Maraging 300 Steel

2017 ◽  
Vol 371 ◽  
pp. 73-77 ◽  
Author(s):  
Adriano Gonçalves Reis ◽  
Danieli Aparecida Pereira Reis ◽  
Antônio Jorge Abdalla ◽  
Antônio Augusto Couto ◽  
Jorge Otubo
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Austenite Transformation ◽  
X Ray ◽  
Xrd Diffraction ◽  
Temperature Solution ◽  
Diffraction Patterns

An in situ high-temperature X-ray diffraction (HTXRD) study in maraging 300 steel was carried out to study the martensite to austenite transformation and effect of time of exposure in the austenite reversion below austenite start temperature. Solution annealed materials were subjected to controlled heating-holding cycles. The first sample was heated at a rate of 10 oC/min from room temperature to 800 oC, showing that the microstructure is completely martensitic (α’110) until 600 oC. From 650 oC until 800 oC, the microstructure is gradually changing from martensitic to austenitic, showed by the increasing peaks of γ111 and reducing peaks of α’110. At 800 oC the microstructure is completely austenitic (γ111). Another sample was heated at 10 oC/min from room temperature to 600 oC and held for 4 hours. At 600 oC, at 0 h time of exposure, only a martensitic peak was observed. An austenite peak can be observed after some time of exposure at this temperature. The volume fraction of austenite increased with increasing time of exposure at 600 oC, reaching 50/50 volume fraction after 4 hours of exposure. XRD diffraction patterns for the same sample that was held for 4 hours at 600 oC and then cooled down in air to room temperature showed the same intensity of austenite and martensitic peaks found in situ at 600 oC for 4 hours (retained austenite), with the volume fraction of 50/50 of austenite and martensite phases. The HTXRD technique can be used to identify and quantify martensite to austenite transformation and austenite retention.

MICROSTRUCTURE OF FeCo–Cu NANOGRANULAR FILMS WITH GIANT MAGNETORESISTANCE

2007 ◽  
Vol 21 (20) ◽  
pp. 1297-1305
Author(s):  
CHANGZHENG WANG ◽  
PEIMING ZHANG ◽  
YIQING ZHANG ◽  
XIAOGUANG XIAO ◽  
YONGHUA RONG ◽  
...  
Keyword(s):  
Giant Magnetoresistance ◽  
Room Temperature ◽  
Volume Fraction ◽  
X Ray Diffraction ◽  
Coherent Interface ◽  
X Ray ◽  
Cu Films ◽  
Transmission Electron ◽  
The Relationship ◽  
Fcc Structure

A series of ( Fe 50 Co 50)x Cu 1-x granular films were prepared using a magnetron-controlled sputtering system. The microstructure and giant magnetoresistance of FeCo–Cu films deposited at room temperature and then annealed at various temperatures were investigated through X-ray diffraction, transmission electron microscope and conventional four-probes method under room temperature, respectively. The results revealed that FeCo–Cu films consisted of fine FeCo granules uniformly dispersed in the Cu matrix and formed fcc structure. Meanwhile the Cu (111) interplaner lattice spacing decreased with increasing magnetic volume fraction (x) due to the presence of the metal coherent interface strains and FeCo–Cu alloying. Upon varying the magnetic volume fraction (x), the giant magnetoresistance of as-deposited FeCo–Cu films reached a maximum of about 0.7% at the volume fraction of 31%, corresponding to the fact that the giant magnetoresistance has a non-monotonic relationship with the granule size. In addition, the relationship between the full width at half maximum (FWHM) or the sensitivity of the giant magnetoresistance and the volume fraction are discussed in detail.

Study of NiFe/SiO2 Nanocomposites

2001 ◽  
Vol 703 ◽  
Author(s):  
S. Hui ◽  
Y.D. Zhang ◽  
T. D. Xiao ◽  
Mingzhong Wu ◽  
Shihui Ge ◽  
...  
Keyword(s):  
Chemical Reaction ◽  
Composite System ◽  
Volume Fraction ◽  
Treatment Temperature ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Sio2 Nanocomposites ◽  
Wet Chemical ◽  
Fe Alloys

ABSTRACT(Ni75Fe25)v/(SiO2)1-v nanocomposites with v =0.5, 0.7, and 1.0, where 75 denotes the atomic percent of Ni in the Ni-Fe alloy phase and v denotes the volume fraction of the magnetic constituent in the composite, were synthesized using a wet chemical approach. The x-ray diffraction and TEM experiments show that the synthetic NiFe/SiO2 is a two-phase composite system in that an amorphous insulating SiO2 layer coats each Ni-Fe particle. The Ni-Fe particle is in a fcc Ni-Fe alloy state. Its size can be controlled over a rather large range between 5 nm to 70 nm by adjusting the reaction parameters. Particular attention was paid to reduce the chemical reaction temperature so as to insure the smallness of the particle size. Meanwhile, measurements of the saturation magnetization indicated that the higher the heat treatment temperature, the more complete the chemical reaction to form the Ni-Fe alloys from precursor materials.

Electron Microscopy of Human Gallstones

1971 ◽  
Vol 29 ◽  
pp. 296-297
Author(s):  
C. Wolpers ◽  
R. Blaschke
Keyword(s):  
Electron Microscopy ◽  
Room Temperature ◽  
Bile Pigment ◽  
X Ray Diffraction ◽  
Triclinic Crystal System ◽  
X Ray ◽  
Follow Up Study ◽  
Infra Red ◽  
Main Components

Scanning microscopy was used to study the surface of human gallstones and the surface of fractures. The specimens were obtained by operation, washed with water, dried at room temperature and shadowcasted with carbon and aluminum. Most of the specimens belong to patients from a series of X-ray follow-up study, examined during the last twenty years. So it was possible to evaluate approximately the age of these gallstones and to get information on the intensity of growing and solving.Cholesterol, a group of bile pigment substances and different salts of calcium, are the main components of human gallstones. By X-ray diffraction technique, infra-red spectroscopy and by chemical analysis it was demonstrated that all three components can be found in any gallstone. In the presence of water cholesterol crystallizes in pane-like plates of the triclinic crystal system.

Electron Microscope study of commensurate-incommensurate phase transition in BaZnGeO4

1990 ◽  
Vol 48 (4) ◽  
pp. 172-173
Author(s):  
Naoki Yamamoto ◽  
Makoto Kikuchi ◽  
Tooru Atake ◽  
Akihiro Hamano ◽  
Yasutoshi Saito
Keyword(s):  
Phase Transition ◽  
Electron Microscope Study ◽  
Room Temperature ◽  
Hexagonal Lattice ◽  
Ferroelectric Materials ◽  
Temperature Phase ◽  
X Ray Diffraction ◽  
X Ray ◽  
Periodic Arrays ◽  
Modulation Wave Vector

BaZnGeO4 undergoes many phase transitions from I to V phase. The highest temperature phase I has a BaAl2O4 type structure with a hexagonal lattice. Recent X-ray diffraction study showed that the incommensurate (IC) lattice modulation appears along the c axis in the III and IV phases with a period of about 4c, and a commensurate (C) phase with a modulated period of 4c exists between the III and IV phases in the narrow temperature region (—58°C to —47°C on cooling), called the III' phase. The modulations in the IC phases are considered displacive type, but the detailed structures have not been studied. It is also not clear whether the modulation changes into periodic arrays of discommensurations (DC’s) near the III-III' and IV-V phase transition temperature as found in the ferroelectric materials such as Rb2ZnCl4.At room temperature (III phase) satellite reflections were seen around the fundamental reflections in a diffraction pattern (Fig.1) and they aligned along a certain direction deviated from the c* direction, which indicates that the modulation wave vector q tilts from the c* axis. The tilt angle is about 2 degree at room temperature and depends on temperature.

Xenon Trioxide Adducts of O-Donor Ligands; [(CH3)2CO]3XeO3, [(CH3)2SO]3(XeO3)2, (C5H5NO)3(XeO3)2, and [(C6H5)3PO]2XeO3

2018 ◽  
Author(s):  
Katherine Marczenko ◽  
James Goettel ◽  
Gary Schrobilgen
Keyword(s):  
Room Temperature ◽  
Triphenylphosphine Oxide ◽  
Donor Ligands ◽  
Mechanical Shock ◽  
X Ray Diffraction ◽  
X Ray ◽  
Oxygen Coordination ◽  
Xenon Trioxide ◽  
Distorted Octahedra ◽  
Coordination Spheres

Oxygen coordination to the Xe(VI) atom of XeO<sub>3</sub> was observed in its adducts with triphenylphosphine oxide, dimethylsulfoxide, pyridine-N-oxide, and acetone. The crystalline adducts were characterized by low-temperature, single-crystal X-ray diffraction and Raman spectroscopy. Unlike solid XeO<sub>3</sub>, which detonates when mechanically or thermally shocked, the solid [(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>PO]<sub>2</sub>XeO<sub>3</sub>, [(CH<sub>3</sub>)<sub>2</sub>SO]<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub>,<sub> </sub>and (C<sub>5</sub>H<sub>5</sub>NO)<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub> adducts are insensitive to mechanical shock, but undergo rapid deflagration when ignited by a flame. Both [(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>PO]<sub>2</sub>XeO<sub>3 </sub>and (C<sub>5</sub>H<sub>5</sub>NO)<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub> are air-stable whereas [(CH<sub>3</sub>)<sub>2</sub>SO]<sub>3</sub>(XeO<sub>3</sub>)<sub>2</sub> slowly decomposes over several days and [(CH<sub>3</sub>)<sub>2</sub>CO]<sub>3</sub>XeO<sub>3</sub> undergoes adduct dissociation at room temperature. The xenon coordination sphere of [(C<sub>6</sub>H<sub>5</sub>)<sub>3</sub>PO]<sub>2</sub>XeO<sub>3</sub> is a distorted square pyramid which provides the first example of a five-coordinate XeO<sub>3</sub> adduct. The xenon coordination spheres of the remaining adducts are distorted octahedra comprised of three Xe---O secondary contacts that are approximately trans to the primary Xe–O bonds of XeO<sub>3</sub>. Quantum-chemical calculations were used to assess the Xe---O adduct bonds, which are predominantly electrostatic σ-hole bonds between the nucleophilic oxygen atoms of the bases and the σ-holes of the xenon atoms.

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