Mixture Of NH3 Research Articles

純鉄の浸窒焼入れ組織

Austenite formation on the surface of pure iron during nitriding in a mixture of NH3 and H2 gases and surface hardening due to formation of iron-nitrogen martensite by subsequent quenching were investigated. In nitriding at 973 K at a partial pressure of NH3(fNH3) of 5% and 10%, austenite layer is formed at the surface while double-layered structures consisting e-Fe2~3N and austenite are developed at fNH3 of 20%. In addition, at these high fNH3, voids are formed in e-Fe2~3N nitride as well as austenite with high nitrogen content. At fNH3 of 5% and 10%, the growth rates of austenite accords with parabolic growth law and become faster with increasing fNH3. On the other hand, after prolonged treatment at fNH3 of 20%, thickness of the nitrided zone is less than that for 10% due to substantial formation of voids and resultant emission of nitrogen from the surface. The hardness of the nitrided zone is nearly the constant at 800HV in the specimen nitrided at fNH3 of 5% whereas softening near the surface occurs in the specimens nitrided at fNH3 of 10% and 20% due to formation of the retained austenite and the voids.

Chemical Vapor Deposition of Cobalt Nitride and its Application as an Adhesion-Enhancing Layer for Advanced Copper Interconnects

An interlayer of face centered cubic (fcc) Co4N has demonstrated significant improvements in adhesion between copper and diffusion barrier layers. This fcc phase of Co4N was prepared by chemical vapor deposition (CVD) using bis(N-tert-butyl-N′-ethyl-propionamidinato)cobalt(II) and a reactant mixture of NH3 and H2 at substrate temperatures from 100 to 180°C. The Co/N atomic ratio and the phase of cobalt nitride film can be modified by adjusting the ratio of NH3 and H2 in the gas feedstock. The cobalt nitride films prepared by CVD are smooth, highly conformal, and stable against intermixing with copper up to at least 400°C. This fcc cobalt nitride material has very strong adhesion to copper due to the small lattice mismatch (−1 to 2%) between fcc-Co4N and fcc Cu. Copper wires should be stabilized against failure by electromigration when fcc cobalt nitride interlayers are placed between the copper and surrounding diffusion barriers.

The structural characterization of (NH4)2B10H10 and thermal decomposition studies of (NH4)2B10H10 and (NH4)2B12H12

The structure of (NH4)2B10H10 (1) was determined through powder XRD analysis. The thermal decomposition of 1 and (NH4)2B12H12 (2) was examined between 20 and 1000 °C using STMBMS methods. Between 200 and 400 °C a mixture of NH3 and H2 evolves from both compounds; above 400 °C only H2 evolves. The dihydrogen bonding interaction in 1 is much stronger than that in 2. The stronger dihydrogen bond in 1 resulted in a significant reduction by up to 60 °C, but with a corresponding 25% decrease in the yield of H2 in the lower temperature region and a doubling of the yield of NH3. The decomposition of 1 follows a lower temperature exothermic reaction pathway that yields substantially more NH3 than the higher temperature endothermic pathway of 2. Heating of 1 at 250 °C resulted in partial conversion of B10H102− to B12H122−. Both 1 and 2 form an insoluble polymeric material after decomposition. The elements of the reaction network that control the release of H2 from the B10H102− can be altered by conducting the experiment under conditions in which pressures of NH3 and H2 are either near, or away from, their equilibrium values.

Properties study of silicon carbide thin films prepared by electron cyclotron resonance plasma technology

Silicon carbide films were deposited at two deposition temperatures 350 °C and 450 °C by means of ECR plasma reactor with two gas mixtures: (1) gas mixture, SiH4 (5 sccm), CH4 (14 sccm), Ar (6 sccm), NH3 (2 sccm) and (2) gas mixture SiH4 (5 sccm), CH4 (14 sccm), H2 (6 sccm), NH3 (2 sccm). The concentration of species in the SiC films was determined by Rutherford backscattering spectrometry (RBS) and elastic recoil detection (ERD) analytical method simultaneously. Chemical compositions were analyzed by infrared (IR) spectroscopy. Photoluminescence (PL) spectra were measured at 300 K. The RBS and ERD results showed that the concentrations of Si and C in the films are practically the same. The concentration of hydrogen decreased from 30 to 22 at.% with an increasing sample deposition temperature. The films contain a small amount of nitrogen and oxygen. IR results showed the presence of Si-C, Si-N, Si-H, C-H and Si-O bonds. PL results showed the decrease of the PL intensity with an increasing sample deposition temperature.

Effects of Pyrolysis Conditions on Yield of Bio-Chars from Pine Chips

The influences of temperature, heating rate, purge gas type, and flow rate on the yield of chars produced from pyrolyzing southern pine chips were investigated. Pyrolysis temperatures were between 450°C and 1,000°C, with heating rates of 0.5°C/min, 1.0°C/min, 10°C/min, 30°C/min, 50°C/min, and 100° C/min. Purge gases, nitrogen (N2), hydrogen (H2), and N2–H2 mixture (10% H2), were used at flow rates from 100 to 1,000 mL/min. Pine char yield decreased as temperature, heating rate, or purge gas flow rate increased. Two regions with significantly different decrease rates of pine char yield can be identified for temperature or heating rate as they increase. The yield decrease rate turning points were 550°C and 10°C/min for yield-temperature and yield-heating rate charts, respectively. The pine char yield was lowest when hydrogen was the purge gas and highest with nitrogen.

Influence of Hydrogen on the Plasmas Nitriding Process of 35CrMo Steel

The mechanism of the formation of active nitrogen atoms and the function of hydrogen molecules for the dissociation of the mixture of nitrogen and hydrogen in the plasma nitriding process are discussed in this paper. The results show that the nitrided case thickness of nitrided samples become thinner and the surface hardness decreases with the increase of cathode voltage. Active nitrogen atoms mainly result from non-elastic collision between positive ions H2+ and neutral particles N2 for N2-H2 mixture plasma nitriding at 550V cathode voltage, the volume percent of e-Fe3N and the superficial nitrogen concentration of plasma nitrided case decrease with the increase of the mixture ratio of N2/H2. However, active nitrogen atoms mainly result from non-elastic collision between energetic positive ions H2+, N2+and neutral particles N2 for N2-H2 mixture plasma nitriding at 650V cathode voltage. The existence of a few of nitrogen molecules makes critical energy of positive ions H2+ dissociating neutral N2 molecules drop to 26.06eV and the cathode voltage threshold value become 490V.

ChemInform Abstract: Sodium Magnesium Amidoborane: The First Mixed‐Metal Amidoborane.

AbstractNa2Mg(NH2BH3)4 is synthesized by ball milling (200 rpm, He atmosphere, 80 min) of appropriate mixtures of NaH, MgH2, and NH3·BH3.

Kinetics of Low Temperature Nitriding of Precipitation Hardened Stainless Steel

The paper presents results of research on nitrided layers on precipitation hardened stainless steel, known also as 1RK91 (Sandvik NanoflexTM). Samples were subjected to low temperature nitriding. The influence of nitriding parameters on nitriding kinetics was investigated. The nitriding process was carried out in a mixture of NH3 50% and products of its dissociation as well as in 100% ammonia atmosphere at temperature range 425-475°C. To investigate the kinetics of nitrided layer formation, the nitriding time changes between 2 and 8 h. The obtained diffusion layers were examined using the following methods: light and scanning electron microscopy, XRD phase analysis. The distribution profiles of selected chemical elements were acquired using optical spectrometry GDOES.

N-doped anodic titania nanotube arrays for hydrogen production

Titanium dioxide (TiO2) nanotube arrays are grown in a mixed electrolyte by anodizing process. The anodic nanotubes for N-doping were calcinated at 773 K in a tube furnace with a mixture of NH3 and Ar gas. The photocatalytic activity of N-doped TiO2 nanotubes was carried out in a water-splitting reaction under UV and visible light irradiation. Various characterization techniques (Scanning electron microscopy, X-ray diffractometry, X-ray photo-electron spectroscopy, etc.) are used to study the surface morphology, phase of structure, and binding energy.

Double Differential Cross Sections and Generalized Oscillator Strength Distributions of Ammonia

The absolute double differential cross section (DDCS), the generalized oscillator strength distribution (GOSD), and the ionization efficiency of ammonia (NH3) were investigated from the threshold to 40 eV under the condition of 200 and 400 eV incident electron energies and 6 and 8 degree scattering angles using electron energy-loss spectroscopy and electron- ion coincidence techniques. To determine the absolute values, we used a mixture of helium (He) and NH3 and normalized the measured relative DDCS spectrum by the differential cross section for 21P excitation of He. Our results are in close agreement with previous dipole (e, e) spectroscopy, although the incident electron energy is lower. The ionization efficiency curve obtained from coincidence measurements indicated the existence of doubly excited states that cause neutral dissociation.

High-Yield Synthesis of Well-Crystalline <I>α</I>-Fe<SUB>2</SUB>O<SUB>3</SUB> Nanoparticles: Structural, Optical and Photocatalytic Properties

In this paper, the high-yield facile synthesis, detailed characterization and photocatalytic application of alpha-Fe2O3 nanoparticles are reported. The synthesis was done via simple hydrothermal process by using aqueous mixtures of iron chloride, hexamethylenediamine and NH3 x H2O at 110 degrees C. The morphologies of the synthesized products were examined by using field emission scanning electron microscopy (FESEM) and transmission electron microscopy (TEM) which confirmed that the synthesized structures are almost spherical shaped nanoparticles with the average diameters of -35 +/- 5 nm, and are grown in high yield. The detailed structural characterizations and composition of the as-synthesized nanoparticles were investigated by using X-ray diffraction (XRD), high-resolution TEM (HRTEM), energy dispersive spectroscopy (EDS) attached with FESEM and Fourier transform infrared spectroscopy (FTIR) which substantiated that the as-synthesized nanoparticles are well crystalline and pure alpha-Fe2O3. The UV-Vis absorption spectrum of the synthesized nanoparticles demonstrated the existence of two optical band gaps which correspond to direct and indirect transitions, respectively. The as-synthesized alpha-Fe2O3 nanoparticles exhibit good photocatalytic properties on photocatalytic degradation of methylene blue.

Primordial synthesis of amines and amino acids in a 1958 Miller H 2 S-rich spark discharge experiment

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H(2)S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H(2)S, CH(4), NH(3), and CO(2). A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H(2)S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H(2)S may have played an important role in prebiotic reactions in early solar system environments.

Suppression of Electrical Breakdown in Silicon Nitride Films Deposited by Catalytic Chemical Vapor Deposition at Temperatures Below 200 °C

Silicon nitride (SiN(x)) films for a gate dielectric layer of thin film transistors were deposited by catalytic chemical vapor deposition at a low temperature (< or = 200 degrees C). A mixture of SiH4, NH3 and H2 was used as a source gas. Metal-insulator-semiconductor (MIS) capacitor structures were fabricated for current-voltage (I-V) and capacitance-voltage (C-V) measurements. The breakdown voltage characteristics of the SiN(x) films were improved by the increase of NH3/SiH4 and H2/SiH4 mixing ratios and substrate temperatures. H2 treatment was attempted to improve the breakdown voltage further. A breakdown voltage as high as 6.6 MV/cm was obtained after H2 annealing at 180 degrees C. The defect states inside the SiN(x) films were analyzed by photoluminescence spectra. Silicon dangling bonds (2.5 eV) and nitrogen dangling bonds (3.1 eV) were observed. These defect states inside the SiN(x) films disappeared after H2 annealing. Flat band voltage shifts were observed in C-V curves, and their magnitudes decreased as the defect states inside the SiN(x) films decreased.

Behaviors of Absolute Densities of N, H, and NH3 at Remote Region of High-Density Radical Source Employing N2–H2 Mixture Plasmas

For an innovation of molecular-beam-epitaxial (MBE) growth of gallium nitride (GaN), the measurements of absolute densities of N, H, and NH3 at the remote region of the radical source excited by plasmas have become absolutely imperative. By vacuum ultraviolet absorption spectroscopy (VUVAS) at a relatively low pressure of about 1 Pa, we obtained a N atom density of 9×1012 cm-3 for a pure nitrogen gas used, a H atom density of 7×1012 cm-3 for a gas composition of 80% hydrogen mixed with nitrogen gas were measured. The maximum density 2×1013 cm-3 of NH3 was measured by quadruple mass spectrometry (QMS) at H2/(N2+H2)=60%. Moreover, we found that N atom density was considerably affected by processing history, where the characteristic instability was observed during the pure nitrogen plasma discharge sequentially after the hydrogen-containing plasma discharge. These results indicate imply the importance of establishing radical-based processes to control precisely the absolute densities of N, H, and NH3 at the remote region of the radical source.

Collisional lasing on a self-terminating transition of a helium atom

Laser on a self-contained transition of a helium atom is studied under excitation of the helium mixture with molecular gases by single long-duration (up to 700ns) or double nanosecond pulses. In He — H2O and He — NH3 mixtures, no limitations were found on the pulse repetition rate and the laser pulse duration obtained was equal to that of the pump pulse.

Control of iron nitride formation by a high magnetic field

The influence of high magnetic field on nitriding behavior was investigated in a mixture of NH3 and H2. It was found that high magnetic field could shift the equilibrium of nitriding reaction; this proved that the critical nitrogen potential to form γ′-Fe4N and ε-Fe3N phase was evidently enhanced compared with conventional nitriding. This research provides a new approach for a selective nitriding process.

Trace Addition of Ammonia and Water on the Growth of Cabon Nanotubes Prepared by PECVD Method

A new way was developed to grow carbon nanotubes (CNTs) in the downstream zone of high pressure dielectric barrier discharge plasma. Using Ni coated Si as the catalyzed substrate, CH4 as the carbon source, H2, NH3 and water vapor mixtures as the dilution and etching gas, CNTs were grown under temperatures of 630oC and 750 oC. The effects of various etching gas mixtures on the growth of CNTs were investigated respectively. The CNTs were characterized by SEM and high-resolution TEM. The results show that trace addition of Ammonia and water vapor to the plasma atmospheres can influence CNTs growth strongly. In 15% CH4 gas mixtures, CNTs can grown well within an addition of 3% NH3 which showed an improvement of CNTs quality, but no product was founded when adding the NH3 content over 8%. On the contrary, in 15% CH4 and 8% NH3 gas mixtures, CNTs can grow better when adding a small proportion (2‰-6‰) of water vapor to the etching gas and meanwhile optical emission spectrometry (OES) was applied to diagnositic and explain the effects of trace water vapor on the process of CNTs growth.

Study of DC circuit breaker of H2‐N2 gas mixture for high voltage

AbstractGlobal warming caused by such gases as CO2 is a subject of great concern. Automobile emissions are an especially great problem in this respect. Therefore, hybrid cars are being widely developed and used. Because hybrid cars use electric power and gasoline, their emissions of CO2 are reduced. The electric motor of a hybrid car is driven by a battery, which has large capacity. Therefore, relays must interrupt a high DC current on switching between the electric motor and the gasoline engine, and hydrogen gas‐filled relays are used for the purpose. In interruption tests in which we investigated the basic characteristics of hydrogen gas, the DC current did not reach a current‐zero point. Thus, the current must be coerced to zero by using a high arc voltage. The loss coefficient and arc voltages of hydrogen are high, and we therefore performed interruption tests using a high arc voltage. Interruption tests and dielectric breakdowns test of air, pure hydrogen, and a hydrogen‐nitrogen mixture indicated that an 80%–20% H2–N2 mixture is the most effective. © 2010 Wiley Periodicals, Inc. Electr Eng Jpn, 174(2): 9–17, 2011; Published online in Wiley Online Library (wileyonlinelibrary.com). DOI 10.1002/eej.21042

Daniel Berthelot. Part III. Contribution to photochemistry

Daniel Berthelot (1865-1927) used ultraviolet radiation from the mercury vapor lamp to carry out a series of oxidation and polymerization reactions, and proved that many reactions carried on by electrolysis could also be performed by photolysis. In doing so he discovered a myriad of unknown phenomena. By exposing to the action of UV a mixture of water and carbon dioxide, he achieved the synthesis of formic acid which then condensed and polymerized to produce vegetable sugars. A mixture of CO2 and NH3 gave rise to the simplest of the quaternary compounds, formamide, which represents the starting point for albuminous or proteinic substances, the basis of living matter.

ChemInform Abstract: Coordination Polymer Based on Cyano: Synthesis, Crystal Structure, and Fluorescence.

Abstract[Cu3(CN)3NH3]n is hydrothermally prepared from a mixture of CuCN, NH3, and H2O (autoclave, 180 °C, 72 h, 53% yield).