Preparation of V-based Alloy Membranes using Chemical Transport Process

2002 ◽  
Vol 752 ◽  
Author(s):  
Tetsuya Ozaki ◽  
Yi Zhang ◽  
Masao Komaki ◽  
Chikashi Nishimura
Keyword(s):  
Substrate Temperature ◽  
Chemical Transport ◽  
Fused Silica ◽  
Hydrogen Purification ◽  
Silica Tube ◽  
Source Temperature ◽  
Ni Substrate ◽  
Ni Alloys ◽  
Ni Alloy ◽  
And Diffusion

ABSTRACTNovel preparation process of V-Ni alloys for hydrogen purification membrane using chemical transport was investigated. Vanadium, NH4Cl, and PtCl2 as evaporating source were put in one side of a fused-silica tube, and Ni substrate was put in the other side. The fused-silica tube was sealed in vacuo, and set in a furnace with temperature gradients. Evaporating source temperature was 1173–1273 K. Substrate temperature was 3–100 K higher than the evaporating source temperature. This process consists of formation of HCl from NH4Cl and PtCl2, chemical transport of vanadium under temperature gradient via chlorides in the presence of HCl, and diffusion of the transported V into the Ni substrate. EDX line profile of cross section of the substrates after the process demonstrated that V diffused into the Ni substrates. Distribution of V concentration in the substrates was dependent on the substrate temperature and the temperature difference between the substrate and the evaporating source. Heating condition was optimized to obtain homogeneous V-Ni alloy. When the substrate temperature and evaporating-source temperature were 1228 K and 1223 K, respectively, V diffused homogeneously into the Ni substrate with thickness of 20 μm, and V concentration attained in the substrate was higher than 70at%.

scholarly journals Nuclear Gamma Resonance Study of the Ir —Fe and Ir —Ni Alloy Systems

1971 ◽  
Vol 26 (3) ◽  
pp. 343-352 ◽  
Author(s):  
R.L. Mössbauer ◽  
M. Lengsfeld ◽  
W. Von Lieres ◽  
W. Potzel ◽  
T. Teschner ◽  
...  
Keyword(s):  
Composition Range ◽  
Magnetic Hyperfine Field ◽  
Band Model ◽  
Hyperfine Fields ◽  
Ni Alloys ◽  
Dilute Alloys ◽  
Ni Alloy ◽  
Bulk Magnetization ◽  
Bcc Phase ◽  
Alloy Systems

Abstract The Ir-Fe and Ir-Ni alloy systems were studied over the whole composition range by means of the nuclear resonance absorption of the 73 keV y-rays of 193Jr and of the 14.4 keV y-rays of 57Fe. The magnetic hyperfine field at the Ir-nuclei in Ir-Ni alloys decreases approximately linearly with the Ir concentration from - 460 kOe at 4.2 K in very dilute alloys to zero at about 20 at.-% Ir. This behaviour is paralleled by the decrease of the magnetic moment per Ni atom as determined from bulk magnetization measurements. The hyperfine fields at both Ir and Fe were measured for the ferromagnetic bcc phase of the Ir-Fe system. They turned out to be virtually independent of concentration with values of about -1400 kOe and - 330 kOe, respectively. Linewidths increasing with the Ir concentration indicate a distribution of hyperfine fields. The fee phase of the Ir-Fe system has been found to be paramagnetic at 4.2 K throughout the range of its existence. The dependence of the hyperfine fields on concentration is discussed in terms of a rigid 3d-band model combined with local shielding. A discussion of the concentration dependence of the 193Ir and 57Fe isomer shifts has to take into account lattice expansion as well as band repopulation effects.

Synthesis and Magnetic Properties of Nanocrystalline Co-Ni Alloys: A Review

2012 ◽  
Vol 736 ◽  
pp. 229-240 ◽  
Author(s):  
Sudhakar Panday ◽  
P. Jeevanandam ◽  
B.S. Sunder Daniel
Keyword(s):  
Magnetic Properties ◽  
Binary Alloys ◽  
Synthesis Method ◽  
Surface Oxidation ◽  
Alloy Nanoparticles ◽  
Ni Alloys ◽  
Alloy Particles ◽  
Ni Alloy ◽  
Co Concentration ◽  
Potential Applications

This review article deals with the synthesis, characterization and magnetic properties of Co-Ni nanoalloys. The various physical and chemical methods for the synthesis of Co-Ni alloy nanoparticles are discussed. Co-Ni alloy nanoparticles with different size and shape such as spherical, rods, wires chain-like assembly are found to depend on the synthesis method and experimental condition. The structure of Co-Ni alloys is eitherfcc,hcpor mixedfccandhcpphase and found to depends on size, shape and concentration of Co in the Co-Ni alloys. Sodium hydroxide (NaOH) concentration and Co to Ni ratio influence the shape of bimetallic Co-Ni nanoparticles. Pt nucleating agents produced smaller size of Co-Ni alloy particles compared to Ru and Ag. Higher Co concentration in the Co-Ni alloys also influences the size alloy particles. The magnetic properties of Co-Ni nanoalloys depend on the size, shape and composition of the binary alloys. Surface oxidation of Co-Ni alloy nanoparticles decrease the saturation magnetization and increases with Co concentration in the alloys. The shape of Co-Ni alloy nanoparticles has an influence on coercivity. The microwave absorption properties of the Co-Ni alloys found to depend on the shape, size and composition of the binary alloys. The absorbance peaks shifts to higher frequency with decrease in size of the alloy particles. Potential applications of Co-Ni alloys in various fields are highlighted.

Waveguide Capillary Cell for Low-Refractive-Index Liquids

1997 ◽  
Vol 51 (10) ◽  
pp. 1554-1558 ◽  
Author(s):  
Robert Altkorn ◽  
Ilia Koev ◽  
Amos Gottlieb
Keyword(s):  
Refractive Index ◽  
Thin Layer ◽  
Reflection Loss ◽  
Total Internal Reflection ◽  
Visible Region ◽  
Fused Silica ◽  
Internal Reflection ◽  
Silica Tube ◽  
Transparent Liquid ◽  
Low Refractive Index

We describe a waveguide capillary cell based on a fused-silica tube coated externally with a thin layer of a low-refractive-index ( n = 1.31) fluoropolymer. When filled with a transparent liquid of refractive index greater than that of the fluoropolymer, the cell is capable of transmitting light through total internal reflection. Loss below 1 dB/m is demonstrated throughout much of the visible region for a 530-μm-i.d., 660-μm-o.d. cell filled with water.

scholarly journals Dissolution and Diffusion-Based Reactions within YBa2Cu3O7−x Glass Fibers

Fibers ◽  
2019 ◽  
Vol 8 (1) ◽  
pp. 2 ◽  
Author(s):  
Hanna Heyl ◽  
Shuo Yang ◽  
Daniel Homa ◽  
Carla Slebodnick ◽  
Anbo Wang ◽  
...  
Keyword(s):  
Phase Separation ◽  
Glass Fibers ◽  
Heat Treatments ◽  
Fused Silica ◽  
Miscibility Gap ◽  
Barium Copper ◽  
Yttrium Barium ◽  
Reaction Processes ◽  
And Diffusion ◽  
Subsequent Diffusion

This work presents a thorough identification and analysis of the dissolution and diffusion-based reaction processes that occur during the drawing of YBa2Cu3O7−x (YBCO) glass-clad fibers, using the molten-core approach, on a fiber draw tower in vacuum and in oxygen atmospheres. The results identify the dissolution of the fused silica cladding and the subsequent diffusion of silicon and oxygen into the molten YBCO core. This leads to a phase separation due to a miscibility gap which occurs in the YBCO–SiO2 system. Due to this phase separation, silica-rich precipitations form upon quenching. XRD analyses reveal that the core of the vacuum as-drawn YBCO fiber is amorphous. Heat-treatments of the vacuum as-drawn fibers in the 800–1200 °C range show that cuprite crystallizes out of the amorphous matrix by 800 °C, followed by cristobalite by 900 °C. Heat-treatments at 1100 °C and 1200 °C lead to the formation of barium copper and yttrium barium silicates. These results provide a fundamental understanding of phase relations in the YBCO–SiO2 glass-clad system as well as indispensable insights covering general glass-clad fibers drawn using the molten-core approach.

Modeling Internal Oxidation of Binary Ni Alloys

2011 ◽  
Vol 696 ◽  
pp. 82-87 ◽  
Author(s):  
Georgina Zimbitas ◽  
Willem G. Sloof
Keyword(s):  
Reaction Time ◽  
Numerical Model ◽  
Solubility Product ◽  
Specific Model ◽  
Alloying Element ◽  
Matlab Toolbox ◽  
Internal Oxide ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Oxide Precipitate

A numerical model is presented to simulate the diffusional transport of oxygen and that of an alloying element, within a 1-D binary Ni alloy, leading to the selective oxidation of the alloying element and the formation of an internal oxide precipitate. This specific model is written in MATLAB and, with the aid of the Matlab Toolbox, is coupled to the ThermoCalc extensive database. A reaction time is introduced to overcome problems related to the difficulty of formation of the internal oxide. Two cases are considered: Al as the alloying element for which the solubility product of the oxide forming elements is small, and Mn for which it is large.

Effect of pH on Composition, Structure and Magnetic Properties of Electrodeposited Co-Ni Alloys

2009 ◽  
Vol 68 ◽  
pp. 52-59 ◽  
Author(s):  
T. Mahalingam ◽  
K. Sundaram ◽  
Subramaniam Velumani ◽  
M. Raja ◽  
S. Thanikaikarasan ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Nickel Content ◽  
Cobalt Content ◽  
Soft Magnetic ◽  
Solution Ph ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Sulfate Baths ◽  
Composition Structure ◽  
Kinetics Of

Co-Ni alloy thin films were electrodeposited from sulfate baths at various solution pH values (1.5-5.5) ±0.1. The deposition kinetics of the films was studied using linear sweep voltametry (LSV). XRD studies exhibited fcc and hcp phases for Co-Ni alloys deposited at low and high pH ranges, respectively. EDAX studies showed that the cobalt content increased and nickel content decreased with increase in solution pH. The surface morphology of Co-Ni films were analyzed by scanning electron microscopy. It is found that the Co-Ni alloys synthesized at low pH exhibited soft magnetic properties and the films deposited at higher values revealed hard magnetic properties and the results are discussed.

scholarly journals ANOMALOUS ELECTRODEPOSITION OF Fe-Ni ALLOY COATING FROM SIMPLE AND COMPLEX BATHS AND ITS MAGNETIC PROPERTY

2010 ◽  
Vol 10 (2) ◽  
pp. 108-122 ◽  
Author(s):  
M A Islam
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Magnetic Property ◽  
Current Density ◽  
Coarse Grained ◽  
Soft Magnetic Properties ◽  
Soft Magnetic ◽  
Alloy Electrodeposition ◽  
Ni Alloys ◽  
Ni Alloy

Electrodeposition of Fe-Ni thin films has been carried on copper substrate under various electrodeposition conditions from two simple and six complex baths. Sulfate baths composing of NiSO4. 7H2O, FeSO4.7H2O, H3BO3 and Na2SO4KEYWORDS: Anomalous Electrodeposition, Fe-Ni Coating, Complexing agent, Current Density, Magnetic Property. 1. INTRODUCTION Alloy electrodeposition technologies can extend tremendously the potential of electrochemical deposition processes to provide coatings that require unique mechanical, chemical and physical properties [1]. There has been a great research interest in the development and characterization of iron-nickel (Fe-Ni) thin films due to their operational capacity, economic interest, magnetic and other properties [2]. Due to their unique low coefficient of thermal expansion (CTE) and soft magnetic properties, Fe-Ni alloys have been used in industrial applications for over 100 years [3]. Typical examples of applications that are based on the low CTE of Fe-Ni alloys include: thermostatic bimetals, glass sealing, integrated circuit packaging, cathode ray tube, shadow masks, membranes for liquid natural gas tankers; applications based on the soft magnetic properties include: read-write heads for magnetic storage, magnetic actuators, magnetic shielding, high performance transformer cores. comprise the simple baths whereas complex baths were prepared by adding ascorbic acid, saccharin and citric acid in simple baths. The effect of bath composition, pH and applied current density on coating appearance, composition, morphology and magnetic property were studied. Wet chemical analysis technique was used to analyze the coating composition whereas SEM and VSM were used to study the deposit morphology and magnetic property respectively. Addition of complexing agents in plating baths suppressed the anomalous nature of Fe-Ni alloy electrodeposition. Coatings obtained from simple baths were characterized by coarse grained non-smooth surface with/without microcracks onto it whereas those from complex baths were fine grained with smooth surfaces. Satisfactory saturation magnetization value of 131.13 emu/g in coating was obtained from simple bath. Coatings obtained from complex baths did not show normal magnetization behavior.

scholarly journals Impact of Short-Range Clustering on the Multistage Work-Hardening Behavior in Cu–Ni Alloys

Metals ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 151 ◽  
Author(s):  
Dong Han ◽  
Jin-Xian He ◽  
Xian-Jun Guan ◽  
Yan-Jie Zhang ◽  
Xiao-Wu Li
Keyword(s):  
Work Hardening ◽  
Short Range ◽  
Strain Range ◽  
Work Hardening Behavior ◽  
Hardening Behavior ◽  
Ni Alloys ◽  
Hardening Process ◽  
Ni Content ◽  
Ni Alloy ◽  
Work Hardening Rate

The work-hardening behavior of Cu–Ni alloys with high stacking-fault energies (SFEs) is experimentally investigated under uniaxial compression. It is found that, with the increase of Ni content (or short-range clustering, SRC), the flow stress of Cu–Ni alloys is significantly increased, which is mainly attributed to an enhanced contribution of work-hardening. An unexpected multistage (including Stages A, B, and C) work-hardening process was found in this alloy, and such a work-hardening behavior is essentially related to the existence of SRC structures in alloys. Specifically, during deformation in Stage B (within the strain range of 0.04–0.07), the forming tendency to planar-slip dislocation structures becomes enhanced with an increase of SRC content (namely, increase of Ni content), leading to the occurrence of work-hardening rate recovery in the Cu–20at.% Ni alloy. In short, increasing SRC in the Cu–Ni alloy can trigger an unexpected multistage work-hardening process, and thus improve its work-hardening capacity.

scholarly journals The Corrosion Behavior of Sputter-deposited W-Cr-(4-15)Ni Alloys in NaOH Solutions

1970 ◽  
Vol 24 ◽  
pp. 3-11
Author(s):  
Pom Lal Kharel ◽  
Jagadish Bhattarai
Keyword(s):  
Corrosion Resistance ◽  
Open Circuit Potential ◽  
Chromium Content ◽  
Chemical Society ◽  
Open Circuit ◽  
Ni Alloys ◽  
Ni Alloy ◽  
Naoh Solution ◽  
Order Of Magnitude ◽  
Sputter Deposited

The synergistic effect of chromium addition in the sputter-deposited amorphous or nanocrystalline W-Cr-(4-15)Ni alloys is studied in alkaline NaOH solutions at 25°C, open to air using immersion tests and electrochemical measurements. In 1 M NaOH solution, the addition of chromium to W-Cr-(4-15)Ni alloys containing 42-75 at % chromium increased the corrosion resistance and shifted the open circuit potential more noble so as to show higher corrosion resistance than those of alloy-constituting elements (that is, tungsten, chromium and nickel). The corrosion rates (that is, about 2-5 x 10-3 mm.y-1) of all the examined W-Cr-(4-15)Ni alloys are about two orders of magnitude lower than that of tungsten and nearly one order of magnitude lower than that of chromium metal. The open circuit potential of the W-Cr-(4-15)Ni alloys is generally increased with increasing chromium content in different concentrations of NaOH solutions. The passivity of the WCr-(4-15)Ni alloys is increased with decreasing the concentration of NaOH solutions at 25°C. Keywords: Corrosion resistance; Sputter deposition;  W-Cr-Ni alloy;  NaOH solution; Open Circuit  potential. DOI: 10.3126/jncs.v24i0.2380Journal of Nepal Chemical Society, Vol. 24, 2009 Page: 3-11

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