Energy Technology Data Exchange (ETDEWEB)

This patent describes an improved zinc electrode for a rechargeable zinc-air battery comprising an outer frame and a porous foam electrode support within the frame which is treated prior to the deposition of zinc thereon to inhibit the formation of zinc dendrites on the external surface thereof. The outer frame is provided with passageways for circulating an alkaline electrolyte through the treated zinc-coated porous foam. A novel rechargeable zinc-air battery system is also disclosed.

Energy Technology Data Exchange (ETDEWEB)

The invention comprises an improved rechargeable zinc-air cell/battery having recirculating alkaline electrolyte and a zinc electrode comprising a porous foam support material which carries the active zinc electrode material. 5 figs.

Energy Technology Data Exchange (ETDEWEB)

Dominating factors in plasma nitriding and plasma condition that makes nitriding possible in plasma nitriding process of metals having hard oxide film were studied. In case of stainless steel, oxide film sputtering was easier comparing to nitriding layer. Three phenomena such as sputtering of oxide layer, formation of nitriding layer and sputtering of nitriding layer occurred simultaneously. Nitriding was achieved when the formation of nitriding layer reached the peak comparing to the removal of nitriding layer after the removal of oxide layer. Situations of metallic surface of stainless steel in surface nitriding were divided into four categories and they were, situation where oxide layer remained as it is, situation where nitriding layer was formed although ...

Energy Technology Data Exchange (ETDEWEB)

The present conference discusses plasma-assisted surface coating/modification processes, the applications to date of ion nitriding, the effects of nitrogen on metal surfaces, ion nitriding mechanisms in Cr, Al and Cr + Al-containing 1040 steel, ion nitriding of Al and its alloys, life enhancement for forging dies, novel anode plasma nitriding developments, and a comparative study of the pulsed and dc ion-nitriding behavior in specimens with blind holes. Also discussed are the influence of heating method on ion nitriding, surface hardening of marage steels by ion nitriding without core hardness reduction, plasma nitriding of nodular cast iron sput gears, NbN composites for superconductors, the carburization of tungsten in a glow discharge methane plasma, economic considerations concerning plasma ...

Energy Technology Data Exchange (ETDEWEB)

To clarify the mechanism of plasma nitriding, the authors examined the optical microstructure, the hardness, the precipitation, and the concentration of dissolved nitrogen in Fe-18Cr-9Ni nitrided using plasma in the range of 723-823 K. Compared with ammonia-gas nitriding, the features of plasma nitriding are the formation of small chromium-nitride precipitates (CrN), the absence of an externally nitrided layer, the high concentration of dissolved nitrogen, and the high hardness (HV = 1,200). The diffusion coefficient of nitrogen in the present alloy was determined using the growth rate of the internally nitrided layer, based on calculations used in internal oxidation. Plasma- and gas-nitriding were also compared with respect to the growth rate of the nitrided layer.

Energy Technology Data Exchange (ETDEWEB)

17-4PH stainless steel was modified by direct current (DC) plasma nitriding and titanium nitride film duplex treatment in this study. The microstructure, wear resistance and corrosion resistance were characterized by X-ray diffraction (XRD), pin-on-disk tribological test and polarization experiment. The results revealed that the DC plasma nitriding pretreatment was in favor of improving properties of titanium nitride film. The corrosion resistance and wear resistance of duplex treatment specimen was more superior to that of only coated titanium nitride film.

Energy Technology Data Exchange (ETDEWEB)

As for surface treatment of steel, the ion nitriding method has a lot of advantages and is practically used, while the plasma nitriding is known as a method which is faster in nitriding than the ion nitriding method. However, there are few reports and many unclear points on the plasma nitriding method. In this study, the plasma nitriding of pure iron and SUS304 is conducted using r.f. nitrogen plasma glow discharge to examine composition of the nitrided layers, microstructures, nitriding rate, etc. Moreover, by exposing the specimen once nitrided to H2 plasma, a phenomenon that nitrogen comes out of the specimen surface is examined. It is found from the result that the nitrided layer is divided into a compound layer and a diffusion layer in order from the surface, that in case of ...

Energy Technology Data Exchange (ETDEWEB)

Interest in the tribological properties of plasma nitriding has increased substantially over the past years because plasma nitriding provides a high nitride depth and improved hard facing. The present study examines the tribological properties of AISI H11 plasma nitrided, hot-worked steel. Different nitriding temperatures and durations were considered. Characterization of the composite structures was investigated with wear tests, x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and microhardness tests. The depth profile of the nitrided zone was measured using the nuclear reaction analysis (NRA) technique. Plasma nitriding affected the microhardness, wear properties, and morphology considerably. Increase in process temperature increased the nitride zone depth.

Energy Technology Data Exchange (ETDEWEB)

According to the invention, a zinc foil is arranged between the negative electrode of a zinc/air battery (round cell) and the expansion space compensating for the reactive increase in volume of the zinc powder. This zinc foil functioning as a stop diaphragm particularly ensures, from the very onset, that the zinc filling has a density and compactness necessary for good electronic conductance.

Energy Technology Data Exchange (ETDEWEB)

This paper describes a new idea for zinc-air battery design. The novel idea is a porous zinc electrode surrounded with a supersaturated zincate solution. 3 figs. (JDH)

International Nuclear Information System (INIS)

The effect of a mineralizer, magnesium silicate, on the nitridation of compacts consisting of silicon, clay, silica and silicon carbide was examined in terms of their reaction depth, density, porosity, phase composition and microstructure. It was found that addition of mineralizer slowed down the nitridation significantly. The kinetic process of isothermal nitridation in the presence of magnesium silicate obeys a parabolic rate law. Otherwise it obeys a linear rate law. The results suggest that nitrogen transportation is the limiting step during nitridation when mineralizer is added. The mechanism of nitridation is discussed in terms of phase composition and microstructure. Copyright (2000) The Australian Ceramic Society

British Library Electronic Table of Contents (United Kingdom)

Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni-Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr2N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr...

International Science & Technology Center (ISTC)

Development of Technology for Producing High-Effective Nitride Fuel UN with Controlled Microstructure for Advanced Fast Neutron Nuclear Reactors

International Nuclear Information System (INIS)

Recent research carried out in laboratories showed that Saddle field neutral fast atom beam source is a promising method for nitriding of stainless steel. In the present work, the effect of treatment time on the microstructural and mechanical properties of plasma-nitrided stainless steel sample was investigated by this new method. Plasma nitriding was carried out at 420 deg. C and at a pressure of 0.1 Pa for a time range of 1 to 12 h. SEM-EDX, microhardness tests, optical microscopy and X-ray diffraction (XRD) were used to evaluate the mechanical and structural properties of the nitrided layer. It was found that nitriding time has a pronounced effect on the structural and mechanical properties of low-temperature plasma-nitrided samples and produced a precipitation-free thin hard nitrided layer within a short processing time.

Science.gov (United States)

... Accession Number : ADA547552. Title : Aluminum-Zinc (Al-Zn) Dust Analyses for Recycling Purposes. Descriptive Note : Technical rept. ...

International Nuclear Information System (INIS)

The present work describes the surface improvement and biocompatibility of TiAl_2_4Nb_1_0 intermetallic alloy using rf plasma nitriding. The nitriding process was carried out at different plasma power from 400 W to 650 W where the other plasma conditions were fixed. Grazing incidence X-ray diffractometry (GIXRD), Auger electron spectroscopy (AES), tribometer and a nanohardness tester were employed to characterize the nitrided layer. Further potentiodynamic polarization method was used to describe the corrosion behavior of the un-nitrided and nitrided alloy. It has been found that the Vickers hardness (HV) and corrosion resistance values of the nitrided layers increase with increasing plasma power while the wear rates of the nitrided layers reduce by two orders of magnitude as compared to those of the un-nitrided layer. ...

International Nuclear Information System (INIS)

Results of researches on nitriding process of EJ961 steel are presented in this work. This steel was subjected to nitriding both on the cathode and on the isolated from cathode and anode substrate, that is at so called potential of glow discharged plasma. Nitriding processes were performed using device for glow discharge treatments with cooled anode. (author)

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared.

International Nuclear Information System (INIS)

Low pressure plasmas have some promising advantages for nitriding The separation of plasma generation from the workpiece overcomes several of the major drawbacks of conventional plasma nitriding and also allows independent control of ion flux and energy This opens the possibility of nitriding at lower temperatures so that the process can be extended to a wider range of materials and applications. Copyright (1999) Materials Australia

International Nuclear Information System (INIS)

Short communication. 12 refs., 1 fig.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Microalloyed or high strength low alloy (HSLA) steels are carbon-manganese steels containing small amounts of Nb, V or Ti. The excellent mechanical properties of these alloys, particularly high yield strength, usually obviate the need for expensive quench and tempering operations. Furthermore, the presence of a significant amount of nitride-forming elements in some microalloyed steels has generated interest in the applicability of these alloys as a new generation of nitriding steels. In this paper, a study of the plasma nitriding behaviour of a commercially available microalloyed steel MAXIMA{sup TM} is reported. A comparison is made with a traditional quenched and tempered nitriding steel (En19), plasma nitrided under similar conditions. Optical and scanning electron microscopy in conjunction with microhardness measurements and X-ray diffraction were utilized to characterize the ...

British Library Electronic Table of Contents (United Kingdom)

In this work AISI 1045 steel were duplex treated via plasma nitriding of chromized layer. Samples were pack chromized by using a powder mixture consisting of ferrochromium, ammonium chloride and alumina at 1273K for 5h. The samples were then plasma-nitrided for 5h at 803K and 823K, in a gas mixture of 75%N2+25%H2. The treated specimens were characterized by scanning electron microscopy (SEM), X-ray diffraction (XRD) analysis and Vickers micro-hardness test. The thickness of chromized layer before nitriding was about 8mm and it was increased after plasma nitriding. According to XRD analysis, the chromized layer was composed of chromium and iron carbides. Plasma nitriding of chromized layer resulted in the formation of chromium and iron nitrides and carbides. The hardness of the duplex layer...

Energy Technology Data Exchange (ETDEWEB)

The properties of polycrystalline (Ti, Al)N coatings deposited on non-nitrided, classically plasma-nitrided and low pressure plasma-nitrided AISI H11 steel samples were investigated. The plasma deposition and low pressure plasma nitriding were performed in a Z700-LH magnetron sputter ion plating unit, while a separate unit was used for plasma nitriding of specimens at a pressure of several millibars. The (Ti, Al)N coating was deposited onto all the samples using the same equipment as for the plasma deposition and low pressure plasma nitriding. For the characterization of the composite structures, the following methods were used: scratch test, X-ray diffraction analysis, scanning electron microscopy, scanning tunnelling microscopy and microhardness testing. It was found that plasma nitriding prior to coating deposition strongly affects the ...

Energy Technology Data Exchange (ETDEWEB)

This report summarizes the results of research conducted during the sixteen month continuation of a program to develop rechargeable zinc-air batteries for electric vehicles. The zinc-air technology under development incorporates a metal foam substrate for the zinc electrode, with flow of electrolyte through the foam during battery operation. In this ``soluble`` zinc electrode the zincate discharge product dissolves completely in the electrolyte stream. Cycle testing at Lawrence Berkeley Laboratory, where the electrode was invented, and at MATSI showed that this approach avoids the zinc electrode shape change phenomenon. Further, electrolyte flow has been shown to be necessary to achieve significant cycle life (> 25 cycles) in this open system. Without it, water loss through the oxygen electrode results in high-resistance failure of the cell. The Phase I program, which focused ...

CERN Document Server

Zinc-fingers, which widely exist in eukaryotic cell and play crucial roles in life processes, depend on the binding of zinc ion for their proper folding. To computationally study the zinc coupled folding of the zinc-fingers, charge transfer and metal induced protonation/deprotonation effects have to be considered. Here, by attempting to implicitly account for such effects in classical molecular dynamics and performing intensive simulations with explicit solvent for the peptides with and without zinc binding, we investigate the folding of the Cys2His2 type zinc-finger motif and the coupling between the peptide folding and zinc binding. We find that zinc ion not only stabilizes the native structure, but also participates in the whole folding process. It binds to the peptide at early stage of folding, and directs or ...

Energy Technology Data Exchange (ETDEWEB)

PulsPlasma nitriding is now one of the established nitriding methods. This article describes PulsPlasma nitriding procedures and the boundary conditions necessary. The special features of PulsPlasma technology compared to DC plasma systems are illustrated. In addition, the process benefits of material treatment using a plasma are examined, as is system type. The article concludes with typical applications of PulsPlasma technology for treatment of stainless steel, cold-working steel, hot-working steel and sintered steel. (orig.)

Energy Technology Data Exchange (ETDEWEB)

Silicon nitride hybrid ball bearings used in high temperature applications undergo mechanical and environmental degradation. To study the surface chemistry of silicon nitride, a CAChe{trademark} Worksystem* has been used to generate the clusters and corresponding transmission vibrational spectra of silicon nitride. In the present study, the effect of surface conditions on the surface chemistry and wear degradation of silicon nitride was evaluated. Infrared reflection spectroscopy (IRRS) used to determine molecular orientations shows a difference in reflectance spectra for fractured and as-received.

Energy Technology Data Exchange (ETDEWEB)

The authors report a novel configuration for a zinc-particle, packed-bed anode in which an open structure of high hydraulic permeability is maintained indefinitely in a cell with closely spaced walls by the formation of particle bridges and associated gaps. The configuration minimizes electrolyte pumping costs, allows rapid refueling and partial recharge, and provides for 100% zinc consumption. This approach benefits zinc/air fuel batteries by allowing nearly continuous operation and fuel recycle without commercial infrastructure; it benefits Zn/[Fe(CN){sub 6}]{sup {minus}3} batteries by eliminating shape-change and polarization problems found with planar anodes.

Energy Technology Data Exchange (ETDEWEB)

Simultaneous nitriding and ageing heat treatments of precipitation hardenable tool steel was carried out inside a DC-pulsed plasma nitriding reactor. A single heat treatment cycle was done, as the plasma nitriding and age hardening processes occur approximately at the same ranges of temperatures and times. Specimens of Cr-Ni-Mo-Al age hardenable steel, in the solubilized and solubilized and aged conditions, were tested. Plasma nitriding and ageing, carried out at 500 deg. C for times ranging between 2 and 8 h, increased the surface hardness up to 1000 HV, producing case depths between 100 and 200 {mu}m. The core hardness of solubilized samples increased from 30 to 39 Rockwell C after the plasma nitriding treatment proving the possibility of nitriding and ageing at the same treatment cycle. The pre-aged samples did not show any overageing after the simultaneous ...

Energy Technology Data Exchange (ETDEWEB)

A series of experiments have been conducted on AISI 5140 low alloy steel using a hollow cathode discharge-assisted plasma nitriding apparatus with the aim of elucidating the role of substrate bias voltages in plasma nitriding process. For comparison, some samples were nitrided with applied substrate bias (-50 V) while other samples were nitrided at floating potential. Treatments were carried out in NH{sub 3} atmosphere of 150 Pa at temperatures ranging from 450 {sup o}C to 550 {sup o}C for 2 h, 4 h, and 6 h. The nitrided samples were characterized by optical microscopy, X-ray diffraction and micro-hardness measurement. The corrosion behaviors were evaluated using anodic polarization tests in 3.5% NaCl solution. The results showed that the microstructure and phase constituents of the nitride layers were strongly influenced by the bias voltages. It was also ...

Energy Technology Data Exchange (ETDEWEB)

Gas nitridation has shown excellent promise to form dense, electrically conductive and corrosion-resistant Cr-nitride surface layers on Ni-Cr base alloys for use as proton exchange membrane fuel cell (PEMFC) bipolar plates. Due to the high cost of nickel, Fe-base bipolar plate alloys are needed to meet the cost targets for many PEMFC applications. Unfortunately, nitridation of Fe-base stainless steel alloys typically leads to internal Cr-nitride precipitation rather than the desired protective surface nitride layer formation, due to the high permeability of nitrogen in these alloys. This paper reports the finding that it is possible to form a continuous, protective Cr-nitride (CrN and Cr{sub 2}N) surface layer through nitridation of Fe-base stainless steel alloys. The key to form a protective Cr-nitride surface layer was ...

Energy Technology Data Exchange (ETDEWEB)

A number of properties in steel components are detrimentally influenced when exposed to hydrogen environments. Under these conditions, atomic hydrogen is adsorbed on the steel surface, then absorbed and preferentially transported towards tri-dimensional stressed regions in the crystal lattice and into defects such as interfaces or dislocations. The hydrogen embrittlement susceptibility is strongly influenced by various microstructural parameters including the type of inclusions, steel composition and heat treating conditions. One of the alternatives employed in minimizing hydrogen embrittlement is the use of surface barriers for hydrogen permeation. In particular, the presence of surface nitride layers in steels can be considered as an effective barrier. Nitride steel surface layers can be produced by plasma nitriding with the concomitant benefits of improved surface hardness, as well as superior wear and fatigue ...

Energy Technology Data Exchange (ETDEWEB)

The properties of AlN make this material very attractive for optical, electronic, and tribological application. Also, if the AlN could be formed on the Al surface to enhance its surface properties, Al could be applied for the lightening of machine parts. However, a dense oxide film exists on the surface of Al, which prevents the formation of the Al nitride even during plasma nitriding and plasma coating process. In this study, plasma nitriding has been tried to form an AlN layer on Al after the surface activation processes. During the plasma nitriding, the density of the nitrogen ions was amplified by means of controlling the power of the Al substrates. The film thickness, microstructural features and the mechanical properties such as hardness and wear properties of the AlN layer were examined as a function of the process parameters of pretreatment and plasma nitriding

International Nuclear Information System (INIS)

This study was the analyse the relationship between properties of ion nitrided Fe sintered material and parameters of plasma nitriding process. Pure fe sintered materials (relative density : 92%) were fabricated by hot-pressing and nitrided under pulsed DC plasma for 4 hours. The large number of parameters in plasma diffusion treatment allows close control of the process so that surface layers with defined microstructures and properties can be obtained. The number of micropores in nitriding layer can be reduced in pulsed DC plasma by reducing the plasma power and by varying the gas mixture. The phase constitution of compound layer of nitrided Fe sintered material were influenced by gas mixture (N_2 : H_2) and pulsed ratio (pulse on/off time ratio).

Energy Technology Data Exchange (ETDEWEB)

The Electric Fuel Limited (EFL) refuelable zinc-air battery system is currently being tested in a number of electric vehicle demonstration projects, the largest of which is a field test of zinc-air postal vans sponsored chiefly by Deutsche Post AG (the German Post Office). The zinc-air battery is not recharged electrically, but rather is refueled through a series of mechanical and electrochemical steps that will require a special infrastructure in commercial application. As part of the German Post Office field test program, Electric Fuel designed and constructed a pilot zinc anode regeneration plant in Bremen, Germany. This plant is capable of servicing up to 100 commercial vans per week, which is adequate for the field test vehicle fleet. This paper will describe the design and operation of each of the areas and devices within the plant.

Energy Technology Data Exchange (ETDEWEB)

This work was initiated to examine the effect of frequency and treatment temperature on the formation of nitrided layers and surface characteristics during plasma nitriding. Plasma nitriding experiments were performed with 316L austenitic stainless steel at the temperatures 400 .deg. C and 500 deg. C using a pulsed d.c. plasma with various frequencies in an atmosphere of N{sub 2}-H{sub 2} gas mixture. The microstructure and thickness of the nitrided layer and morphology of the nitrided surface were investigated using OM, SEM, XRD, EDS and AFM. XRD patterns revealed that the surface layer formed at 400 deg. C consisted of S phase only and CrN+Fe{sub 4}N nitrides at 500 .deg. C and no change of phase composition with frequency was observed. The compound layer thickened slightly with increased frequency. Also, the surface roughness increased as the frequency of the ...

International Nuclear Information System (INIS)

Aluminium nitride (AlN) is a very interesting ceramic because of its combination of properties such as high thermal stability, high hardness and an unusual combination of high thermal and low electrical conductivity. But it is very difficulty to obtain an AlN layer on the aluminium substrates by thermochemical nitriding process. Since a thin film of aluminium oxide existing on the surface of every aluminium substrate prevents the nitrogen atoms from diffusing into the aluminium lattice. However, it is possible to sputter the oxide film away from the aluminium surface in a glow discharge with the use of plasma nitriding technique and to allow the formation of AlN layer on the aluminium bulk. In the present work specimen of aluminium Al 99.5 has been plasma nitrided in a modified plasma nitriding unit, in which a diffusion pump was used to obtain an especially low partial pressure of ...

Energy Technology Data Exchange (ETDEWEB)

The effects of the plasma nitriding with the formation of compound nitride and diffusion zones and of the boronising with the different ion doses on hydrogen distribution and hydrogen induced deterioration of a surface layer were examined in the case of Armco iron. Electrochemical studies of hydrogen permeation rate, hydrogen vacuum extraction measurements, optical and scanning microscopy, X-ray diffraction and elastic recoil detection analysis (ERDA) were used. Accumulation of entering hydrogen within the various constituent zones of the modified layer inhibits the hydrogen transport into the metal and thus, decreases the mean hydrogen content in the deeper zones and in the core. Hydrogen accumulation within the compact nitride zone causes the expansion of the nitride lattice, nitride phase transformation and deterioration. The ion boronising enhances the hydrogen effects in the ...

Energy Technology Data Exchange (ETDEWEB)

With specific energy of more than 200 Wh/kg, the Electric Fuel zinc-air battery delivers as much as eight times the energy of lead-acid traction battery, more than twice the energy of the nearest advanced-battery competitor, and as much energy as a tank of gasoline. (author)

UK PubMed Central (United Kingdom)

BackgroundZhx1 to 3 (zinc-fingers and homeoboxes) form a set of paralogous genes encoding multi-domain proteins. ZHX proteins consist of two zinc fingers followed...Full Text Available

UK PubMed Central (United Kingdom)

Objective: To evaluate effects of epigallocatechin-3-gallate (EGCG) on the viability, membrane properties, and zinc distribution, with and without the presence of Zn²⁺, in human prostate...Full Text Available

UK PubMed Central (United Kingdom)

Zinc modulates the activity of glutamic acid decarboxylase, the rate limiting enzyme in the synthesis of gamma-aminobutyric acid (GABA), which is a major inhibitory neurotransmitter. Low cerebrospinal...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

No abstract prepared

International Nuclear Information System (INIS)

The low alloy steels were nitrided in the plasma atmosphere generated by using hollow cathode discharge. For comparison, specimens of 40 Cr steel were in two different potential states. One kind is isolated from cathode and anode between them the discharge was created. The other kind is placed on the plate which is connected to the cathode. The nitriding was carried out at different temperatures. The surface morphology, phase of compound layers and microhardness profiles were analyzed. The optical microscopy observation and X-ray diffraction showed that the compound layers were formed in all experiments. The results of the nitriding treatment are weakly dependent on the potentials applied on the specimens.

Energy Technology Data Exchange (ETDEWEB)

We report tests of a refuelable zinc/air battery of modular, bipolar-cell design, intended for fleet electric busses and vans. The stack consists of twelve 250-cm{sup 2} cells built of two units: (1) a copper-clad glass-reinforced epoxy board supporting anode and cathode current collectors, and (2) polymer frame providing for air- and electrolyte distribution and zinc fuel storage. The stack was refueled in 4 min. by a hydraulic transfer of zinc particles entrained in solution flow.

KoreaScience (Korea)

Full Text Available

Energy Technology Data Exchange (ETDEWEB)

For the development of a rechargeable zinc/air battery, La{sub 0.6}Ca{sub 0.4}CoO{sub 3}-catalyzed (perovskite) bifunctional oxygen electrodes and pasted zinc electrodes were prepared and tested in monopolar zinc/air cells. The cells were cycled in moderately alkaline electrolyte. The maximum power as well as the cycle life of the cells were investigated. Up to 450 cycles could be reached, and attractive specific energies and powers were obtained. (author) 3 figs., 4 refs.

Energy Technology Data Exchange (ETDEWEB)

The surface of low alloy steel (En40B) has been engineered in the plasma of a glow discharge via plasma nitriding and ion plating of titanium nitride (TiN) coatings on the nitrided substrates with the purpose of enhancing the surface properties and fatigue strength. The nitriding response of the steel has been accessed by the evaluation of phase composition, layer thickness, hardness profile, residual stresses and nitrogen and carbon distributions. The wear and fatigue characteristics of the plasma-nitrided steel have been investigated and simple models have been developed to describe the influence of such properties as depth and strength of the nitrided case on the fatigue limit and load-bearing capacity of the nitrided steel. In order to further improve the tribological properties and load-bearing capacity of the low alloy steel, a duplex ...

Energy Technology Data Exchange (ETDEWEB)

Crankshafts of the pearlitic-sorbitic nodular cast iron type JUS NL.80 (similar to DIN GGG-80) heat treated to get a tensile strength of 820-900 GPa (i.e. a Vickers hardness of 268-295 HV) were plasma and ammonia gas nitrided. The glow discharge plasma nitriding was performed for 20 h at about 500degC in a gas mixture of 55% N{sub 2} and 45% H{sub 2}. The gas nitriding was performed for 28 h at 510degC in the ammonia gas. Evaluation of the nitrided surfaces was conducted by optical microscopy, X-ray diffractometry and microhardness measurements. Journal and crank pin dimensions and surface roughness were measured both before and after nitriding. Bending fatigue testing of crankshafts was performed using a fatigue testing rig. The fatigue limit was evaluated at 5.0x10{sup 6} cycles. The fractures happened at the transition radius of the journal with cracks starting beneath the ...

British Library Electronic Table of Contents (United Kingdom)

Deposition of CN-based films by a novel version of active screen plasma nitriding, aiming at surface modification of polymers, is reported. The approach relies on the use of pure graphite as the grid material, which was found to act both as an active screen and as a dry source of carbon atoms for the synthesis of thin films consisting mainly of a stoichiometric CN layer with columnar-type structure and dome-like nanostructured morphology.

Energy Technology Data Exchange (ETDEWEB)

Stainless steels can be nitrided at temperatures {<=}400 C to increase their hardness and wear resistance without a decreasing of their excellent corrosion resistance. Structure and properties of the surface layers produced by plasma nitriding and plasma immersion ion implantation in this temperature range were tested. There are negligible differences in the structure of the produced surface layers in spite of different interaction principles of the used technologies. However there are clear differences between the case of different steels. The case of ferritic chromium steels mainly consists of {epsilon}-nitride. Whereas the cases of austenitic and ferritic austenitic steels are characterized by expanded austenite. The corrosion resistance of the steels is reduced by nitriding only, if evident CrN-formation occurs. (orig.) 11 refs.

Energy Technology Data Exchange (ETDEWEB)

With the aim of optimizing the nitriding process, experimental studies of the plasma nitriding of four selected steels were carried out, using a d.c. glow discharge. The process parameters were varied systematically. By means of transmission and scanning electron microscopy and X-ray diffraction, the microstructures, including the thicknesses of the compound zones and the diffusion zones of the nitrided steels, were obtained. Using cross-sectional samples and a micro-Vickers indenter, hardness depth profiles were also obtained. From the time and temperature dependences of the hardness profiles, effective diffusion constants and corresponding activation enthalpies were obtained. Furthermore, in an attempt to shed some light on the atomistic nitriding mechanisms, the glow discharges were studied by measuring energy spectra of the energetic ions hitting the cathode (the steel test specimens). It was shown ...

British Library Electronic Table of Contents (United Kingdom)

Nitridation of Cr-bearing alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant CrN or Cr2N base surfaces of interest for a range of electrochemical devices, including fuel cells, batteries, and sensors. This paper presents results of exploratory studies of the nitridation of commercially available, high Cr (30-35wt%) Ni-Cr alloys and a ferritic high Cr (29wt%) stainless steel for proton exchange membrane fuel cell (PEMFC) bipolar plates. A high degree of corrosion resistance in sulfuric acid solutions designed to simulate bipolar plate conditions and low ICR values were achieved. Oxygen impurities in the nitriding environment were observed to play a significant role in the nitrided surface structures that formed, with detrimental effect...

British Library Electronic Table of Contents (United Kingdom)

In the present work, the plasma nitriding behavior of a nickel based dental alloy was investigated. Plasma nitriding experiments carried out under constant gas mixture (15% H2?85% N2) for different process parameters including time (4, 6, 10, and 20?h) and temperature (400, 450, 500, and 550??C). Depending on nitriding parameters, it was found that triple or double layers formed on the surface of the samples. Increasing of treatment time and temperature has resulted in a double layer. ?N1 layer was in formed all nitrided samples. However, ?N2 layer is formed only at low temperatures and in short times. Layer growth of nickel based alloys increases until a critical time or a critical temperature reached. Above these critical values, it is observed that the layer thickness decreases. It was ...

Energy Technology Data Exchange (ETDEWEB)

Ti and its alloys (Ti-6Al-4V) have been used in different engineering applications due to their several outstanding properties. Nevertheless, their use in practical applications is limited in many cases due to their poor tribological property. Researches are ongoing on surface modification of Ti based materials by different plasma and ion based techniques to overcome this problem. However, the conventional plasma nitriding techniques have several problems such as formation of an arc, increased possibility of surface contamination due to a comparatively higher operating pressure, production of a very thin nitrided layer after a long processing time, etc. In this present work, the possibility of a new low-pressure plasma nitriding process using a Plasma Enhanced Chemical Vapor Deposition (PECVD) based saddle field fast atom beam source on a Ti-6Al-4V alloy sample is investigated. Plasma nitriding was ...

Energy Technology Data Exchange (ETDEWEB)

To avoid the drop in corrosion resistance of stainless steels in conventional nitriding (precipitation of CrN), low-temperature techniques like ion implantation, plasma immersion ion implantation (PIII, PI{sup 3}) and low-temperature plasma nitriding were developed. In this investigation, four stainless-steel grades (ferritic: X6Cr17, austenitic-ferritic: X2CrNiMoN22.5.3, austenitic: X8CrNiTi18.10 and X5CrNi18.10) were plasma-nitrided between 250 and 500 C. Nitrogen-enriched layers with a high nitrogen content were produced, leading to a significant increase in surface hardness. X-ray diffraction indicated that CrN did not precipitate if treatment temperatures did not exceed 400 C. 'Expanded austenite' formed in the austenitic and duplex steels and {epsilon}-nitride (Fe{sub 2}N{sub 1-x}) in the ferritic steel. The optically visible structure of the nitrided cases ...

Energy Technology Data Exchange (ETDEWEB)

Chromium electroplated AISI 316L stainless steel was nitrided using inductively coupled plasma (ICP) for application in the bipolar plate of a polymer electrolyte membrane fuel cell (PEMFC). A continuous and thin chromium nitride layer was formed at the surface of the samples after ICP nitriding for 2 h at 400 C. The interfacial contact resistance (ICR) and corrosion resistance in simulated PEMFC operating conditions were higher than the required values, while they varied with the applied dc bias voltage during the nitriding process. The ICR value decreased with an increase in bias voltage. Potentiodynamic polarization measurements showed that all of the nitrided samples had excellent corrosion resistance with a current density of {proportional_to}10{sup -7} A cm{sup -2} at the cathode. It was also found that the oxygen content at the surface was not increased after the corrosion ...

International Nuclear Information System (INIS)

A wear-resistant nitrided layer was formed on a 304L austenitic stainless steel substrate by DC plasma nitriding. Effects of DC plasma nitriding parameters on the structural phases, micro-hardness and dry-sliding wear behavior of the nitrided layer were investigated by optical microscopy, X-ray diffraction, scanning electron microscopy, micro-hardness testing and ring-on-block wear testing. The results show that the highest surface hardness over a case depth of about 10 #mu#m is obtained after nitriding at 460 deg. C. XRD indicated a single expanded austenite phase and a single CrN nitride phase were formed at 350 deg. C and 480 deg. C, respectively. In addition, the S-phase layers formed on the samples provided the best dry-sliding wear resistance under the ring-on-block contact configuration test.

Science.gov (United States)

Multiple treatment of engineering surfaces can provide improved surface properties that cannot be obtained by a single surface treatment. Consequently, this study investigates the effects of laser melting on the microstructures of plasma nitrided Ti-6Al-4V alloy. The study consists of two parts. In the first part, governing equations pertinent to the laser melting process are developed, and temperature variation across the melted zone is predicted. In the second, an experiment is conducted to nitride the surface of the alloy through plasma nitriding process and to melt the plasma nitrided and the untreated alloy surfaces with a CO2 laser beam. The resulting metallurgical changes are examined using x-ray diffraction (XRD), bdenergy-dispersive spectrometry (EDS), and scanning electron microscopy (SEM) techniques. It is shown that three distinct nitride layers are formed in the ...

Energy Technology Data Exchange (ETDEWEB)

Plasma nitriding is usually used for ferrous materials to improve their surface properties. Knowledge of the properties of thin surface layers is essential for designing engineering components with optimal wear performance. In our study, we investigated the microstructural, mechanical and tribological properties of plasma- and pulse plasma-nitrided AISI 4140 steel in comparison to hardened steel. The influence of nitriding case depth as well as the presence of a compound layer on its tribological behaviour was also examined. Plasma and pulse plasma nitriding were carried out using commercial nitriding processes. Nitrided samples were fully characterised, using metallographic, SEM microscopic, microhardness and profilometric techniques, before and after wear testing. Wear tests were performed on a pin-on-disc wear testing machine in which ...

Energy Technology Data Exchange (ETDEWEB)

The Ti-6Al-4V alloy was treated by inductively coupled rf plasma nitriding. The effects of plasma-processing time in the range of 5-35 min on the microstructure and the mechanical properties of the plasma-nitrided Ti-6Al-4V samples were studied. The plasma power input was adjusted at 450 W and pure N{sub 2} gas was introduced to establish a treatment pressure of 8.0-8.4 x 10{sup -2} mbar. The characteristics of the nitrided layers have been investigated by microhardness testing, surface roughness measurements, optical microscopy, and x-ray diffraction. The results show that the surface microhardness increases as the plasma-processing time increases to reach 2000 HV0.1 at a plasma-processing time of 35 min. A high nitriding rate of 2.81 {mu}m{sup 2} s{sup -1} at a plasma-processing time of 25 min was achieved. The formation of the hard phases TiN, Ti{sub 2}N, and Ti(N) in the Ti-6Al-4V surfaces are found ...

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The aim of this work is to describe the processes during plasma nitriding of Nb-containing, powder metallurgy prepared (PM) tool steel. PM steel was studied containing 2.5% C, 3.3% Si, 6.2% Cr, 2.2% Mo, 2.6% V, 2.6% Nb and 1.0% W, produced by melt atomization and hot isostatic pressing. The hardened and tempered steel was plasma nitrided at temperatures ranging from 470 to 530 deg. C. The nitriding time was 30-180 min. Optical microscopy, electron microscopy, XRD, EDS, WDS and hardness measurements were used to study the steel's properties, microstructure, phases and chemical composition. The nitriding temperature of 470 deg. C was found to be unsuitable for practical use because the layers prepared at this temperature were non-uniform. The compound layer formed by M{sub 2,3}(C,N) and M{sub 4}N was found after nitriding at temperatures of 500 and 530 deg. C for at least 60 ...

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The Ti and Ti-Al coatings were deposited onto hot-worked AISI H11 steel substrates and plasma nitrided at 900 C. The Ti coated samples were successfully nitrided, while cracking and delamination of the Ti-Al coating was observed during nitriding. The formation of [delta]-TiN and [epsilon]-Ti[sub 2]N phases were detected after plasma nitriding of the Ti coating. During plasma treatment of the Ti-Al coating, the initial Ti[sub 3]Al and Al phases were paartially transformed into TiAl phase. The martensite transformation of the substrate material was found. The as-deposited Ti coating has a fibrous structure, while the structure of the as-sputtered Ti-Al coating is columnar. The superficial Vickers microhardness of plasma-nitrided Ti coating was 2200 HV 0.03 and the critical load of higher than 50 N indicates very good coating-to-substrate adhesion. (orig.)

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Nitridation of Cr-bearing alloys can yield low interfacial contact resistance (ICR), electrically- conductive and corrosion-resistant CrN or Cr2N base surfaces of interest for a range of electrochemical devices, including fuel cells, batteries, and sensors. This paper presents results of exploratory studies of the nitridation of two high Cr (30-35 wt%) commercially available Ni-Cr alloys and a ferritic high Cr (29 wt.%) stainless steel for proton exchange membrane fuel cell (PEMFC) bipolar plates. A high degree of corrosion resistance in sulfuric acid solutions designed to simulate bipolar plate conditions and low ICR values were achieved via nitridation. Oxygen impurities in the nitriding environment were observed to play a significant role in the nitrided surface structures that formed, with detrimental effects for the Ni-Cr base alloys, but beneficial effects for the stainless ...

Energy Technology Data Exchange (ETDEWEB)

This document reports the progress and accomplishments of a 16 month program to develop a rechargeable zinc-air battery for electric vehicle propulsion, from October 1988 through January 1990. The program was the first stage in the transition of alkaline zinc electrode technology, invented at Lawrence Berkeley Laboratory, to private industry. The LBL invention teaches the use of a copper metal foam substrate for the zinc electrode, in combination with forced convection of electrolyte through the foam during battery operation. Research at LBL showed promise that this approach would avoid shape change (densification and dendrite growth), the primary failure mode of this electrode. The program comprised five tasks; (1) cell design, (2) capacity maximization, (3) cycle testing, (4) materials qualification, and (5) a cost/design study. The cell design contemplates a plate and frame stack, with alternating ...

International Nuclear Information System (INIS)

The sheath plasma characteristics changing with the negative bias applied to the substrate during electron cyclotron resonance plasma nitriding are studied. The sheath characteristics obtained by a Langmuir single probe and an ion energy analyzer show that when the negative bias applied to the substrate is increasing, the most probable energy of ions in the sheath and the full width of half maximum of ions energy distribution increase, the thickness of the sheath also increases, whereas the saturation current of ion decreases. It has been found from the optical emission spectrum that there are strong lines of N_2 and N_2"+. Based on the experiment results the mechanism of plasma nitriding is discussed

International Nuclear Information System (INIS)

X-ray fluorescence analysis was used to determine the zinc content of the ''Perilacin'' powder and the ZnO content of the ''Epiderman-pix'' powder. The characteristic Ksub(#alpha#) line of zinc was excited using a "1"4"7Pm/Mo source (10"7 s"-"1) and the molybdenum Ksub(#alpha#) line (17.47 keV). 4 to 5% Zn and 45 to 49% ZnO were determined with a NaI(Tl) scintillation detector. The radiation intensity was found to decrease with particle size. (M.K.).

Energy Technology Data Exchange (ETDEWEB)

A numerical model has been developed to simulate the charging and discharge behaviour of an electrically rechargeable alkaline zinc-air battery. Further a galvanostatic experiment including three charge/discharge cycles has been performed. The cell voltages, the Zn electrode potentials versus a Zn reference, and the O{sub 2} electrode potentials versus a Zn reference calculated with the model are in fairly good agreement with the corresponding experimental data. The model is expected to be useful for zinc-air battery design and for analysis of experimental data. (author)

Energy Technology Data Exchange (ETDEWEB)

In this paper, the influence of plasma nitriding at temperature 720 deg. C for 20 h on the surface microstructure and interface microstructure of electroplated chromium coating was investigated. In these conditions, interdiffusion, mixing and reaction phenomena of elements originating from the substrate and coating material are more likely to occur, thus increasing the bonding strength between the coating and carbon steel substrate. The change of the structures from the substrate side to the coating surface, and the effect of the substrate steel on the interface structure were studied by cross-sectional transmission electron microscope observation (XTEM). The nitride layer formed on the surface was analyzed by X-ray diffraction method (XRD). After treatment at above conditions a 6-7 {mu}m thick nitride compound layer was formed in surface region and the same thick carbide compound layer was also formed in the interface ...

Energy Technology Data Exchange (ETDEWEB)

In this work, the pulse plasma nitriding process of pure iron is modelled using a kinetic model derived from the Fick's laws. This approach based on the error function model allows to simulate the growth kinetics of a biphase configuration consisting of {gamma}'-Fe{sub 4}N{sub 1-x} and {epsilon}-Fe{sub 2-3}N iron nitrides under specified conditions. By coupling the kinetics data about the diffusivities of nitrogen in {alpha}-Fe, {gamma}' and {epsilon} phases to the thermodynamic description of the Fe-N phase diagram, it is possible to evaluate the kinetic constant at each growing phase interface, the thickness of nitrided layer, and predict the nitrogen concentration profiles. The comparison between the experimental and theoretical results shows the reliability of the simulation results.

Energy Technology Data Exchange (ETDEWEB)

Thin passive layers of uranium nitride were formed by nitriding pure metallic uranium in non-equilibrium, low pressure radio-frequency plasma of nitrogen. Plasma nitriding at low substrate temperature of 230 C-250 C was found to cause the formation of adherent layers of uranium sesquinitride ({alpha}-U{sub 2}N{sub 3}) which provide a considerable protection against hydrogen attack. The characteristics of these passivation layers were determined by X-ray diffraction and Auger electron spectroscopy. The incipient hydriding kinetics of the plasma-treated samples were compared with those of untreated and nitrogen-ion implantation ones, utilizing a hot-stage microscope that was monitored continuously with a TV camera and videotape. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The objective of the current study was the gradual development of the formation of the nitride layer during inductive r.f. plasma nitriding. The study centers on characterization of refined layers and plasma diagnostics in the vicinity of the sample, and raises critical questions of how the layers and interfacial microstructure might affect the near-surface properties. The composition of the plasma near the surface of the sample (plasma layer) was examined by optical emission spectroscopy and mass spectrometry during plasma nitriding and while sputtering the sample after the nitriding process. It was observed that during the nitriding process, the plasma layer contains Ti, NH[sub n] species, N (or/and N[sup +]), H[sub n] species (or/and H[sup +][sub 2]). However, when the nitrided sample was exposed to argon plasma, Ti, Al and NH were observed. It was found that ...

Energy Technology Data Exchange (ETDEWEB)

Cold plasma nitriding treatment was performed to improve the corrosion resistance of C38 carbon steel. Nitriding process was conducted using a radiofrequency nitrogen plasma discharge for different times of treatment on non-heated substrates. The modification of the corrosion resistance characteristic of the C38 steel due to the treatment in acid medium (1 M HCl) were investigated by gravimetric and electrochemical tests such as potentiodynamic polarisation curves and electrochemical impedance spectroscopy (EIS). It was shown that the plasma nitriding treatment improves the corrosion resistance. Indeed, in the gravimetric tests, nitrided samples showed lower weight loss and lower corrosion rate in comparison to untreated one. In the Tafel polarisation tests, the nitrided samples showed greatly reduced corrosion current densities, anodic dissolution and also retarded the hydrogen ...

International Nuclear Information System (INIS)

Austenitic stainless steel AISI 304 has been nitrided by radio frequency (rf) plasma containing various nitrogen-hydrogen gas mixtures, in order to study the effect of hydrogen on structure and magnetic properties of the formed compound layer. The thermal temperature has been measured at the vicinity of the samples. The compound layer thus produced has been characterized using, X-ray diffractometer and vibration sample magnetometer. Providing the total pressure of nitrogen and hydrogen is held constant, the addition of hydrogen up to 50% gives new structural phases. The magnetization values of the plasma treated samples are strongly dependent on the percentage of H_2 in the gas phase. An excessive amount of hydrogen (#approx#75%) on the other hand, retards the nitriding process. The surface temperature of the sample and plasma condition is crucial factors for nitriding process.

Energy Technology Data Exchange (ETDEWEB)

This report is an examination and analysis of the zinc-air system as the motive power source for electric vehicle propulsion. Various versions of the zinc-air system and operating schemes along with their advantages and disadvantages are discussed. Baseline cost calculations are also presented in order to compare the cost effectiveness of each of the systems. The treatise is conceptual in nature and is not based on new experimental work. The information is based on published literature and investigations carried out at ERC in the past. The study also includes recommendations and suggestions in areas that require further research and development work to achieve a smooth transition from the conceptual stage to a practical, viable, and cost effective system.

British Library Electronic Table of Contents (United Kingdom)

Abstract BACKGROUND: In Brazil, the usual forms of zinc (Zn) supply to coffee plants have limitations that compromise the element availability to the plant. This study proposes to test an alternative approach to supplying the nutrient to Coffea arabica L. using trunk implanted zinc tablets. Additionally, the effect of Zn on the production and quality of coffee beans was also evaluated. RESULTS: The highest total coffee bean production was recorded in plants implanted with Zn tablets (TA), while the lowest was recorded in the control treatment, without zinc supply (WZn), reaching a bianual production of 188.2 and 130.1 60-kg bags of processed beans per hectare, respectively. In the treatments where Zn were applied as tablet implantation or as foliage spraying (SZn); the bean size was larger...

International Nuclear Information System (INIS)

The dithiocarbamate and thiuram compounds, including disulfiram, were compared for their efficacies in influencing tissue distribution of a trace dose of intravenously injected lead plus "2"0"3Pb in rats. The tested compounds were sodium diethyldithiocarbamate (DEDTC), sodium dimethyldithiocarbamate (DMDTC), tetraethylthiuram disulfide (disulfiram), a complex of zinc and manganese ethylenebisdithiocarbamate (mancozeb), manganese ethylenebisdithiocarbamate (maneb), sodium monomethyldithiocarbamate (metham), zinc propylene bisdithiocarbamate (propineb), tetramethylthiuram disulfide (thiram), zinc ethylenebisdithiocarbamate (zineb), and zinc dimethyldithiocarbamate (ziram). The results of this study show that interactions can occur between lead and DEDTC, DMDTC, disulfiram, metham, thiram, and ziram, resulting in increased levels of lead in brain and probably potentiation of the neurotoxic effects of lead.

Energy Technology Data Exchange (ETDEWEB)

An investigation was conducted into alternative techniques for zinc and electrolyte regeneration and reuse in the refuelable zinc/air battery that was developed by LLNL and previously tested on a moving electric bus using cut wire. Mossy zinc was electrodeposited onto a bipolar array of inclined Ni plates with an energy consumption of 1.8 kWh/kg. Using a H{sub 2}-depolarized anode, zinc was deposited at 0.6 V (0.8 kA/m{sup 2}); the open circuit voltage was 0.45 V. Three types of fuel pellets were tested and compared with results for 0.75 mm cut wire: spheres produced in a spouted bed (UCB); coarse powder produced by gas-atomization (Noranda); and irregular pellets produced by chopping 1-mm plates of compacted zinc fines (Eagle-Picher, Inc.). All three types transported within the cell. The coarse powder fed continuously from hopper to cell, as did the compacted pellets (< ...

International Nuclear Information System (INIS)

Nitrogen has been added to stainless steels to improve mechanical strength and corrosion resistance. High nitrogen steel production is limited by high gas pressure requirements and low nitrogen solubility in the melt. One way to overcome this limitation is the addition of nitrogen in solid state because of its higher solubility in austenite. However, gas and salt bath nitriding have been done at temperatures around 550 C, where nitrogen solubility in the steel is still very low. High temperature nitriding has been, thus proposed to increase nitrogen contents in the steel but the presence of oxide layers on top of the steel is a barrier to nitrogen intake. In this paper a modified plasma nitriding process is proposed. The first step of this process is a hydrogen plasma sputtering for oxide removal, exposing active steel surface improving nitrogen pickup. This is followed by a nitriding step where high ...

Energy Technology Data Exchange (ETDEWEB)

Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr{sub 2}N, CrN, TiN, V{sub 2}N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of proton exchange membrane (PEM) single-cell fuel cell studies of stamped and pre-oxidized/nitrided developmental Fe-20Cr-4V weight percent (wt.%) and commercial type 2205 stainless steel alloy foils. The single-cell fuel cell behavior of the stamped and pre-oxidized/nitrided material was compared to as-stamped (no surface treatment) 904L, 2205, and Fe-20Cr-4V stainless steel alloy foils and machined graphite of similar flow field design. The best fuel cell behavior among the alloys was exhibited by the pre-oxidized/nitrided Fe-20Cr-4V, which exhibited {approx}5-20% better peak ...

Energy Technology Data Exchange (ETDEWEB)

In this paper, aluminium nitride synthesis is carried out by direct laser irradiation onto an aluminium target surface in a nitrogen containing atmosphere. The influence of various processing parameters on the microstructure of AlN thin films is investigated in order to improve their tribological properties. The main microstructural characteristics: nature, concentration, in depth distribution and morphology of various phases are studied versus processing parameters by TEM and GIXD. (author). 2 refs., 1 fig., 2 photos.

Energy Technology Data Exchange (ETDEWEB)

Chromium nitride/Cr coating has been deposited on surface of 316L stainless steel to improve conductivity and corrosion resistance by physical vapor deposition (PVD) technology. Electrochemical behaviors of the chromium nitride/Cr coated 316L stainless steel are investigated in 0.05 M H{sub 2}SO{sub 4}+2 ppm F{sup -} simulating proton exchange membrane fuel cell (PEMFC) environments, and interfacial contact resistance (ICR) are measured before and after potentiostatic polarization at anodic and cathodic operation potentials for PEMFC. The chromium nitride/Cr coated 316L stainless steel exhibits improved corrosion resistance and better stability of passive film either in the simulated anodic or cathodic environment. In comparison to 316L stainless steel with air-formed oxide film, the ICR between the chromium nitride/Cr coated 316L stainless steel and carbon paper is about 30 m{omega} cm{sup 2} that is ...

Wastenet

... Zinc-carbon/air and alkaline-manganese batteries can be reprocessed using a number of different methods, which include smelting and other thermal-metallurgical processes to ... Citron in France - thermal-metallurgical reprocessing primarily of zinc-carbon/air and alkaline-manganese (including older ones containing mercury), but also NiMH, ...

UK PubMed Central (United Kingdom)

Zinc tetraaminophthalocyanine-Fe₃O₄ nanoparticle composites were prepared by organic-inorganic complex technology and characterized. It has been proved that the ZnTAPc dispersed...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Prior to an industrial-scale test of zinc/air batteries at Greven, the TUeV Bayern-Sachsen carried out preliminary tests on behalf of the Deutsche Bundespost. The results were quite promising: The energy density of the new battery is ten times as high as that of conventional lead batteries, and the battery-powered test vehicle had a range of up to 300 km. (orig.)

Energy Technology Data Exchange (ETDEWEB)

A zinc-air battery in a case is described including a zinc particle bed supported adjacent the current feeder and diaphragm on a porous support plate which holds the particles but passes electrolyte solution. Electrolyte is recycled through a conduit between the support plate and top of the bed by convective forces created by a density of differential caused by a higher concentration of high density discharge products in the interstices of the bed than in the electrolyte recycle conduit. 7 figures.

International Nuclear Information System (INIS)

Defects are produced in zinc by 6.1 MeV #alpha#-particle irradiation at 4.2 K and the subsequent recovery between 4.2 and 22 K. No evidence is found for free migration of an interstitial in the temperature range investigated. The recovery spectra reveal a series of substages which are ascribed to recombination of close Frenkel pairs. (author).

British Library Electronic Table of Contents (United Kingdom)

Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr2N, CrN, TiN, V2N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of scale-up studies to determine the feasibility of extending the nitridation approach to thin 0.1mm stainless steel alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. Developmental Fe-20Cr-4V alloy and type 2205 stainless steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. As-treated Fe-20Cr-4V foil exhibited target (low) ICR values, whereas 2205 foil suffered from run-to-run variation in ICR values, ranging up to 2x the...

Energy Technology Data Exchange (ETDEWEB)

Plasma nitriding as a diffusion process is the oldest plasma-assisted process for the surface treatment of metals. Although the use of this process in industry is already well developed and established there are still several scientific questions in the basic understanding of the process and consequently some problems and limits concerning its upscaling for industrial use. Therefore it is necessary to get reproducible results for different geometries of workpieces and for different workload sizes. Correlations between different plasma and treatment parameters, especially in big plants, have to be considered. To understand the process handling using some simple but impressive models the difficulties of treating single parts or mixed workloads are explained. For profitable applications of plasma nitriding plants, some guidelines for the use and selection of a suitable process and a device are given. By the use of a pulsed d.c. power supply for ...

International Nuclear Information System (INIS)

This work describes the ability of ion beam analysis techniques IBA to simultaneously determine the concentration and the possible depth profile of some light elements, such as carbon, oxygen and nitrogen, in matrices of high atomic number Z, such as stainless steel materials. In fact, the nitriding process of some materials has the potential to improve their tribological and mechanical properties and to offer various advantages as compared with other methods used in the modification of surfaces. Gas and Plasma nitriding were applied to certain types of steel, such as AISI-304 and H-13 which are commonly used in the industry, in order to improve their hardness and their surface corrosion resistance. The improvement was correlated with the depth profile of N and the consequent structure variations. More specifically, non-Rutherford elastic backscattering (alpha, alpha) at 5 MeV was performed on different samples, before and after ...

Energy Technology Data Exchange (ETDEWEB)

The usually low wear resistance of titanium materials can be increased by the thermochemical surface treatment nitriding. In result of comparative investigations of gas and plasma nitriding it will be shown that it is possible to obtain a specific variation of the properties in the highly stressed case by means of these both technologies on example of the ({alpha}+{beta}) alloy Ti-6Al-4V. Gas and plasma nitriding was carried out in the temperature range from 650 to 800 C over 4 to 48 h in different gas atmospheres, i.e. 100% NH{sub 3} (gas), 100% N{sub 2} (gas and plasma), 20% H{sub 2} + 80% N{sub 2} and 20% Ar + 20% H{sub 2} (plasma). The temperature range was fixed in the middle of ({alpha}+{beta}) region, because the core properties are influenced negative in the field of {beta}-transustemperature. The relations between the applied nitriding technologies, the layer structure (chemical, phases, ...

Energy Technology Data Exchange (ETDEWEB)

A dense and supersaturated nitrogen layer with higher conductivity is obtained on the surface of austenitic stainless steel 304L by the low temperature plasma nitriding. The effect of plasma nitriding on the corrosion behavior and interfacial contact resistance (ICR) for the austenitic stainless steel 304L was investigated in 0.05M H{sub 2}SO{sub 4}+2ppm F{sup -} simulating proton exchange membrane fuel cell (PEMFC) environment using electrochemical and electric resistance measurements. The experiment results show that the stable passive film is formed after the potentiostatic polarization at the specified anodic or cathodic potentials under PEMFC operation condition, and the plasma nitriding improves slightly the corrosion resistance and decreases markedly the ICR of 304L. The ICR of the plasma nitrided 304L increases after the potentiostatic polarizations for 4h, and lower than 100m{omega}cm{sup 2} at ...

International Nuclear Information System (INIS)

The effect of the nitrogen uptake in #alpha#-iron upon spark erosion in gaseous and liquid ammonia, plasma nitriding, and plasma immersion ion implantation is studied. The resulting phases and hyperfine parameters, measured by the Moessbauer spectroscopy, are discussed from the point of view of initial conditions of their preparation and subsequent heat and/or mechanical treatment. Spark erosion in the ammonia gas produces fine particles with the dominating ferromagnetic #alpha#-Fe phase (50%). The 20% of specimen volume form #alpha#'-Fe and #alpha#''-Fe_1_6N_2 phases. The last 30% occupy the #gamma#'-Fe_4N, ferro- and paramagnetic #epsilon# phases, and #gamma#-Fe(N). Nitriding in the liquid ammonia allows to incorporate the higher content of nitrogen into #alpha#-iron particles which results in the formation of paramagnetic #epsilon#(#zeta#)-Fe_2N phase. This phase also dominates the surface of #alpha#-iron specimen implanted by nitrogen using ...

Energy Technology Data Exchange (ETDEWEB)

In our continued efforts for improving the performance of zinc anodes for a Zn/air battery, we now report the preparation of three alloys and improved performances of anodes made up with these alloys. The alloys contained zinc, nickel, and indium with different weight percentages and were calcined at two different temperatures. Out of the six alloys, the alloy which has a composition of zinc 90%, nickel 7.5% and Indium 2.5% and fired at 500{sup o}C is found to be the best. In the case of the hydrogen evolution reaction, this alloy had its potential shifted to a more negative potential. As far as the cyclic voltammograms were concerned, the difference between the anodic and cathodic part was minimal when compared with other alloys. Surprisingly, this alloy had reversibility even after 100 cycles of the cyclic voltammogram. This is a clear indication that dendrite formation was reduced to a considerable extent. Images taken ...

International Nuclear Information System (INIS)

The ion nitriding treatment is a process widely used in steel alloys to improve the material's properties; such as surface hardness, resistance to wear, fatigue life and resistance to corrosion. But geometric changes in the components can produce during the nitriding process different effects on the behavior of the plasma, such as local variations in the electric field, an empty cathode effect, etc. These in turn can affect among other factors the local temperature and therefore the kinetics of the process, generating variations in the compound layer thicknesses and zone of diffusion, and micro-hardness profile. These heterogeneities limit the effectiveness of the plasma nitriding process, where control and duplication of the surface modification are most important. This work aims to study the effect of the geometry of the pieces treated with ionic nitriding, especially the effect of the orifices. An ...

International Nuclear Information System (INIS)

Conventional plasma carburizing or nitriding for austenitic stainless steels results in a degradation of corrosion resistance. However, a low temperature plasma surface treatment can improve surface hardness without deteriorating the corrosion resistance. The 2-step low temperature plasma processes (the combined carburizing and post nitriding) offers the increase of both surface hardness and thickness of hardened layer and corrosion resistance than the individually processed low temperature nitriding and low temperature carburizing techniques. In the present paper, attempts have been made to investigate the influence of the introduction of Ar gas (0#approx#20%) in nitriding atmosphere during low temperature plasma nitriding at 370 .deg. C after low temperature plasma carburizing at 470 .deg. C. All treated specimens exhibited the increase of the surface hardness with increasing Ar ...

Energy Technology Data Exchange (ETDEWEB)

Thermal (gas) nitridation of stainless steel alloys can yield low interfacial contact resistance (ICR), electrically conductive and corrosion-resistant nitride containing surface layers (Cr{sub 2}N, CrN, TiN, V{sub 2}N, VN, etc.) of interest for fuel cells, batteries, and sensors. This paper presents results of scale-up studies to determine the feasibility of extending the nitridation approach to thin 0.1 mm stainless steel alloy foils for proton exchange membrane fuel cell (PEMFC) bipolar plates. Developmental Fe-20Cr-4V alloy and type 2205 stainless steel foils were treated by pre-oxidation and nitridation to form low-ICR, corrosion-resistant surfaces. As-treated Fe-20Cr-4V foil exhibited target (low) ICR values, whereas 2205 foil suffered from run-to-run variation in ICR values, ranging up to 2 x the target value. Pre-oxidized and nitrided surface structure examination revealed ...

Energy Technology Data Exchange (ETDEWEB)

The first part of a systematic investigation is presented of surface treatments affecting the fatigue behavior of smooth and notched quenched and tempered (Q and T) specimens made of a B-Mn SS2131 ({approx}AISI 15B21H) steel. In this part, the effects of plasma nitriding (nitriding temperature=480 C, time=24 h) on the fatigue strength and notch sensitivity were investigated. Constant stress amplitude plane reversed bending fatigue tests (R=-1) at 47 Hz were conducted using cylindrical plasma nitriding (PN) and Q and T steel specimens with K{sub t}=1.05 and 1.7. The compound layer was found to consists of {epsilon}-phase and {gamma}`-phase. S-N curves show that plasma nitriding improves the fatigue limit by 53 and 115% of Q and T smooth and notched specimens, respectively. The fatigue strength of smooth specimens is improved through the whole fatigue life but only for long fatigue lives for notched ...

Energy Technology Data Exchange (ETDEWEB)

A flexible battery is printed on paper by screen-printing a zinc/carbon/polymer composite anode on one side of the sheet, polymerising a poly(3,4-ethylenedioxythiophene) (PEDOT) cathode on the other side of the sheet, and applying a lithium chloride electrolyte between the two electrodes. The PEDOT cathode is prepared by inkjet printing a pattern of iron(III)p-toluenesulfonate as a solution in butan-1-ol onto paper, followed by vapour phase polymerisation of the monomer. The electrolyte is prepared as a solution of lithium chloride and lithium hydroxide and also applied by inkjet printing on to paper, where it is absorbed into the sheet cross-section. Measurements on a zinc/carbon-PEDOT/air battery in a similar configuration on a polyethylene naphthalate substrate shows a discharge capacity of up to 1.4 mAh cm{sup -2} for an initial load of 2.5 mg zinc, equivalent to almost 70% of the zinc content of ...

Energy Technology Data Exchange (ETDEWEB)

Reactively sputtered tantalum nitride (Ta/sub 2/N) has been investigated as a diffusion barrier between Pd/sub 2/Si and aluminum and CoSi/sub 2/ and Al. Ta/sub 2/N is found to be an excellent matallurgical diffusion barrier for the two systems up to 555 /sup 0/C, with no intermixing observed in Rutherford backscattering and Auger electron spectroscopic studies. Schottky barrier devices n-Si/Pd/sub 2/Si/Ta/sub 2/N/Al were excellent and showed no deterioration after annealing at 500 /sup 0/C. However, similar devices with CoSi/sub 2/ contacts and Ta/sub 2/N barrier showed a creation of high contact resistance between the silicide and the as-deposited nitride.

International Nuclear Information System (INIS)

Nitriding of aluminium 2011 using a radio frequency plasma at higher power levels (500 and 700 W) and lower substrate temperature (500 deg. C) resulted in higher AlN/Al_2O_3 ratios than obtained at 100 W and 575 deg. C. AlN/Al_2O_3 ratios derived from X-ray photoelectron spectroscopic analysis (and corroborated by heavy ion elastic recoil time of flight spectrometry) for treatments preformed at 100 (575 deg. C), 500 (500 deg. C) and 700 W (500 deg. C) were 1.0, 1.5 and 3.3, respectively. Scanning electron microscopy revealed that plasma nitrided surfaces obtained at higher power levels exhibited much finer nodular morphology than obtained at 100 W.

International Nuclear Information System (INIS)

We provide a brief review of our recent results from optically detected magnetic resonance studies of grown-in non-radiative defects in two most important dilute nitride systems-Ga(In)NAs grown on GaAs substrates and Ga(Al,In)NP grown on Si and GaP substrates. These results have led to the identification of defect complexes in the alloys, involving intrinsic defects such as As_G_a antisites and Ga_i self-interstitials. They have also shed light on formation mechanisms of the defects and on their role in non-radiative carrier recombination that is harmful to the performance of potential optoelectronic and photonic devices based on these dilute nitrides.

British Library Electronic Table of Contents (United Kingdom)

Rapid nitridation was used to fabricate reaction-bonded and postsintered -Si6-ZAlZOZN8-Z (Z=1) ceramics with monoclinic ZrO2 added to the starting powder. Thermo-gravimetric analysis revealed that the addition of ZrO2 reduced the starting temperature of the main nitridation reaction. Using a reaction-bonding route with heating rates of 5, 10, and 20C/min, to fabricate -SiAlON ceramics without ZrO2 resulted in unreacted silicon that bled out of the specimens and the Z=1 composition samples did not maintain the original green compact morphology. On the other hand, no such bleeding of melted silicon was observed for samples with ZrO2 additions and the samples following nitridation maintained the original green morphology. The microstructure and mechanical properties of samples produced by rap...

International Nuclear Information System (INIS)

Composite nitrides (such as BN, TiN) are widely used in various industrial applications because of their extreme wear and corrosion resistance, thermal and electrical properties. in order to obtain composite materials with these optimal properties, it is important to elucidate whether any chemical reactions occur at nitride/metal interfaces, e.g., those involving BN-Ti/TiN. Materials of interest include the deposition by PVD of Ti and TiN on BN substrates. Some of these systems were then subjected to varying degrees of physical and thermal alteration. Detailed X-ray photoelectron spectroscopy (XPS) has therefore been rendered of these interfaces using cross-sectional display and sputter etching. Resulting structural and morphological features have been investigated with transmission electron microscopy (TEM) and X-ray diffraction (XRD). Diffusion of the nitridation, oxynitride formation and interfacial growth are of general ...

British Library Electronic Table of Contents (United Kingdom)

A protective film has been developed on the surface of carbon steel in low chloride aqueous environment using a synergistic mixture of an environmentally friendly phosphonic acid, N,N-bis(phosphonomethyl) glycine (BPMG), and zinc ions. Impedance studies of the metal/solution interface indicated that the surface film is highly protective against the corrosion of carbon steel in the chosen environment. Potentiodynamic polarization studies showed that the inhibitor is a mixed inhibitor. X-ray photoelectron spectroscopic analysis (XPS) of the film showed the presence of the elements iron, phosphorus, nitrogen, oxygen, carbon, and zinc. Deconvolution spectra of these elements in the surface film showed the presence of oxides/hydroxides of iron(III), Zn(OH)2, and [Zn(II)-BPMG] complex. This infe...

Energy Technology Data Exchange (ETDEWEB)

The biosorption of lead, copper and zinc ions on Rhizopus arrhizus has been studied for three single-component and two binary systems. The equilibrium data have been analysed using the Freundlich adsorption model. The characteristic parameters for the Freundlich adsorption model have been determined and the competition coefficients for the competitive biosorption of Pb(II)-Cu(II) at pH 4.0 and 5.0, and Pb(II)-Zn(II) at pH 5.0 have been calcualted. For the individual single-component isotherms, lead has the highest biosorption capacity followed by copper, then zinc. The capacity of lead in the two binary systems is always significantly greater than those of the other metal ions, in agreement with the single-component data. Only a partial selectivity for copper ions has been obtained at pH 4.0. (orig.)

Energy Technology Data Exchange (ETDEWEB)

This work presents a comparative study of low-alloy steel nitriding for different possible techniques. Active screen plasma nitriding (ASPN) is a successful surface modification method that has many advantages over the conventional DC plasma nitriding (CPN). The corrosion behavior of 30CrNiMo8 low-alloy steel has been examined using anodic polarization tests in 3.5% NaCl solution under varying conditions of ASPN and CPN processes. The process variables included active screen setup parameters, treatment temperature (550 and 580 deg. C), gas mixture (25/75 and 75/25 of N{sub 2}/H{sub 2}) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the compound layer was studied by X-ray diffraction (XRD), microhardness tests, optical microscopy and scanning electron microscopy (SEM). It was observed that ASPN treated samples surface enhanced corrosion resistance while the temperature and/or hole ...

Energy Technology Data Exchange (ETDEWEB)

Radio frequency (RF) plasma nitriding using different input plasma processing powers (250-600 W) improves the surface of titanium by forming hard phases of TiN, Ti{sub 2}N, and Ti (N) into the surface. The characteristics of the compound layer have been investigated by optical microscopy, microhardness measurements, and X-ray diffraction. The effect of plasma power on the sample temperature, electron temperature, and plasma density was studied using Langmuir double probe. The measured surface hardness value of the compound layer is 2190 HV 0.1 for treated sample at plasma power 500 W. The compound thickness continuously increases as the plasma power increases. The highest nitriding rate of 5.88 {mu}m{sup 2}/s was recorded when the input plasma power was adjusted at 550 W. This high nitriding rate of treated titanium samples is ascribed to the high concentration of active nitrogen species in the plasma atmosphere and the ...

International Nuclear Information System (INIS)

English Oct 1996 p. 352-353 Brazil Maliska, Ana Maria Kuehn, Ingeborg Klein,

Wastenet

...Jhala, G and Rayjada, P A and Raole, P M and Mukherjee, S (2005) Influence of alloying elements on the corrosion properties of steels during plasma nitriding process . Journal of Metallurgy and Materials Science, 47 (1). pp. 31-38. This list was generated on ...

Energy Technology Data Exchange (ETDEWEB)

Notched and smooth cylindrical plasma nitrided (PN) and quench and tempered (Q and T) steel specimens made of a B-Mn SS2131 ({approx}AISI 15B21H) steel have been exposed to constant amplitude plane reversed bending corrosion fatigue tests (R = -1) at 47 Hz in sea water. S - N curves show that sea water suppresses the fatigue limit and reduces fatigue strength (especially at long lives) of smooth and notched Q and T and PN specimens. Plasma nitriding improves the corrosion fatigue resistance of Q and T specimens; this is associated with the good corrosion resistance of {epsilon} and {gamma}`-phases, the enhancement of corrosion and fatigue by compressive residual stresses, and the consumption of H{sup +} ions during reduction of nitrogen. This improvement is more significant for smooth specimens and for long lives. Notch sensitivity of Q and T and PN specimens decreases with fatigue life. Pitting corrosion, cyclic applied stress and residual ...

UK PubMed Central (United Kingdom)

BackgroundChanges in ionic concentration have a fundamental effect on numerous physiological processes. For example, IP₃-gated thapsigargin sensitive intracellular calcium...Full Text Available

UK PubMed Central (United Kingdom)

The development of new methods for gene addition to mammalian genomes is necessary to overcome the limitations of conventional genetic engineering strategies. Although a variety of DNA-modifying enzymes...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The human zinc finger protein genes (ZFX/Y) were identified as a result of a systematic search for the testis-determining factor gene on the human Y chromosome. Although they play no direct role in sex determination, they are of particular interest because they are highly conserved among mammals, birds, and amphibians and because, in eutherian mammals at least, they have active alleles on both the X and the Y chromosomes outside the pseudoautosomal region. We used in situ hybridization to localize the homologues of the zinc finger protein gene to chromosome 1 of the Australian echidna and to an equivalent position on chromosomes 1 and 2 of the playtpus. The localization to platypus chromosome 1 was confirmed by Southern analysis of a Chinese hamster [times] platypus cell hybrid retaining most of platypus chromosome 1. This localization is consistent with the cytological homology of chromosome 1 between the two species. The ...

International Nuclear Information System (INIS)

Radionuclide X-ray fluorescence analysis was used for the determination of iron, calcium, potassium, copper, manganese and zinc in waste water from the production process of citric acid. (author).

UK PubMed Central (United Kingdom)

BackgroundThe zinc-finger transcription factor GLI3 is an important mediator of Sonic hedgehog signaling and crucial for patterning of many aspects of the vertebrate body plan. In...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

The technical feasibility of the solar carbothermal reduction of ZnO has been successfully demonstrated in a pilot plant. The economics of this process is addressed by means of a single sensitivity analysis and a Monte-Carlo risk analysis. A medium-term and a long-term scenario have been investigated, each for a 5 and a 30 MW{sub th} plant. For a discount rate of 15% the zinc production costs vary between 482 and 245 $/t for the medium-term scenario and between 312 and 146 $/t for the long-term scenario, respectively. These costs do not account for the zinc oxide input material. In addition, a risk analysis was conducted for the 30 MW{sub th} long-term scenario. For each input parameter, a probability distribution was estimated and the probability distribution of the zinc production cost was calculated by means of a Monte-Carlo method. The expected mean zinc production costs vary from 95 $/t for a ...

International Nuclear Information System (INIS)

A photon-induced x-ray fluorescence method allowing the simultaneous determination of iron, copper, zinc, bromine and rubidium in human blood and blood plasma samples is described. The method is reliable and has a good sensitivity for a wide range of elements. (author).

UK PubMed Central (United Kingdom)

BackgroundEvidence on human semen quality as it relates to exposure to various metals, both essential (e.g., zinc, copper) and nonessential (e.g., cadmium, lead), is inconsistent....Full Text Available

Energy Technology Data Exchange (ETDEWEB)

This document, Part 2 of Volume 2, provides appendices to this report and includes the following technologies, zinc/air battery; lithium/molybdenum disulfide battery; sodium/sulfur battery; nickel/cadmium battery; nickel/iron battery; iron/oxygen battery and iron/air battery. (FI)

International Nuclear Information System (INIS)

The possibility of surface modification of high-speed steel cutting tool by means of vacuum-plasma treatment including ion nitriding in gas plasma followed by the deposition of wear resistant (Ti, Al)N coatings in metal-gas plasma of a vacuum arc discharge is studied. The regularities of nitrided layer formation and the structure of these layers under various operation conditions of cutting tool are investigated. Optimum conditions of vacuum-plasma treatment providing the best wear resistance of cutting are determined

British Library Electronic Table of Contents (United Kingdom)

Residual stresses are present in engineering components as an unintended consequence of manufacturing processes, but they are also deliberately introduced to beneficial effect during surface engineering procedures. Plasma nitriding is a process of particular importance for forming tools and dies, giving significant advantages in wear, and fatigue resistance through the generation of near-surface compressive residual stresses. A precise knowledge of the level and distribution of residual stresses that exist in engineering components is necessary for an accurate design and prediction of a component's fatigue resistance. However, measurement of residual stresses is not always possible, which is especially true for forming tools. Therefore, other methods for residual stress evaluation and pred...

International Nuclear Information System (INIS)

Iron alloys and aluminum were nitrogen implanted in a controlled oxygen atmosphere and the role of hydrogen on the surface etching mechanisms studied. The surface composition was analyzed by in situ photoemission electron spectroscopy (XPS). In iron alloys, hydrogen strongly etches oxygen, improving nitrogen retention on the surface. On the other hand, hydrogen removes nitrogen from aluminum surfaces, with a deleterious effect on the nitriding effectiveness. The oxygen removal in iron alloys is associated with the catalytic effect of electrons in d-orbitals and the nitrogen removal in aluminum is associated with a steric effect.

International Nuclear Information System (INIS)

Glow discharge plasma nitriding of AISI 304 austenitic stainless steel has been carried out for different processing time under optimum discharge conditions established by spectroscopic analysis. The treated samples were analysed by X-ray diffraction (XRD) to explore the changes induced in the crystallographic structure. The XRD pattern confirmed the formation of an expanded austenite phase (#gamma#_N) owing to incorporation of nitrogen as an interstitial solid solution in the iron lattice. A Vickers microhardness tester was used to evaluate the surface hardness as a function of indentation depth (#mu#m). The results showed clear evidence of surface changes with substantial increase in surface hardness.

Energy Technology Data Exchange (ETDEWEB)

The gel electrolyte for the zinc-air cell was prepared by mixing hydroponics gel with a 6M potassium hydroxide aqueous solution. The self-discharge of cells was characterized by measuring the open-circuit voltage. The effect of a discharge rate of 50mA constant current on cell voltage and plateau hour, as well as the voltage-current and current density-power density were measured and analysed. The electrode degradation after discharge cycling was characterized by structural and surface methods. The oxidation of the electrode surface further blocked the utilization of the Zn anode and was identified as a cause for the failure of the cell. (author)

Science.gov (United States)

The possibility of using lead and lead-bismuth mixed oxides as positive active materials in organic electrolyte lithium cells with a working voltage similar to those of silver zinc cells has been considered. Button cells of SR 44 size have been developed as a test vehicle and studied under various conditions of discharge rate and storage. This paper describes the performance characteristics obtained under these conditions and suggests in conclusion the possible replacement of silver zinc cells by such systems for a large range of low-rate applications on the basis of cost effectiveness.

Energy Technology Data Exchange (ETDEWEB)

The key component for improving the energy efficiency and cycle life of the electrically rechargeable zinc-air battery is the bifunctional air electrode. The air electrodes described in this paper contained different types of carbon black as the substrate for the perovskite catalyst (La{sub 0.6}Ca{sub 0.4}CoO{sub 3}). Morphological and physical properties of the carbon substrates play an important role in enhancing the activity and stability of the bifunctional air electrode. Current-potential curves and cycle-life tests were applied in order to gather information on the activity and stability of these electrodes. (authors)

Energy Technology Data Exchange (ETDEWEB)

This contribution describes our research and development effort towards an electrically rechargeable zinc/air battery which is capable of meeting the demands of a scaled power profile (driving-cycle tests). The power profiles DST (Dynamic Stress Test) and ECE15-L (European Driving Cycle for alkaline Batteries) were applied to our 200 and 50 cm{sup 2} electrically rechargeable Zn/O{sub 2} cells with nominal capacities of 30 and 7.5 Ah, respectively. (authors)

Energy Technology Data Exchange (ETDEWEB)

Carbon steel, copper, zinc and aluminium samples were exposed in different sizes with known ambient parameters in Gran Canaria Island and atmospheric corrosion was investigated. Weight-loss measurements used to determine corrosion damage were complemented with metallographic and XP S determination in order to characterize the structure and morphology of surface corrosion products. The ambient aggressiveness could be well evaluated from meteorological and pollution data. All atmospheric corrosion and environmental data were statistically processed for establishing general corrosion damage functions for carbon steel, copper, aluminium and zinc in terms of Gran Canaria extreme meteorological and pollution parameters. (Author)

International Nuclear Information System (INIS)

By means of an audio frequency plasma polymerisation ultra-thin gradient plasma polymer layers were deposited on zinc and zinc-coated iron. The aim was to generate an interfacial polymeric layer which bonds to an oxidised metal as well as to a subsequently applied organic coating and acts as an interfacial barrier layer for ions and water. Surface modifications were done in an in situ plasma cell with infrared reflection absorption spectroscopy (IRRAS). The zinc surface was first activated by an oxygen plasma to provide a freshly oxidised and contamination free oxide surface. The intermediate stages of the surface reactions could be revealed. Carbon dioxide molecules as oxidation products adsorbed on the growing zinc oxide and were desorbed at a later stage. An organosilicon plasma polymer was deposited directly on top of the oxide layer from a hexamethyldisilane (HMDS) plasma. Afterwards a cyclohexene ...

International Nuclear Information System (INIS)

Thermo-reactive diffusion chromizing followed by pulsed plasma nitriding were carried out on AISI 52100 and 8620 bearing steels. The chromized samples were pulse-plasma nitrided for 5 h at 500 deg. C in various N_2-H_2 gas mixtures. The coated steels were characterized using scanning electron microscopy, X-ray diffraction and microhardness testing. The unlubricated wear behaviors of only chromized and duplex treated steels were investigated in ball-on-disc system tests at room temperature. X-ray diffraction patterns of the duplex treated samples containing H_2 indicated the formation of dominant CrN and Cr_2N nitrides as well as the formation of Cr_3C_2 and Cr_7C_3 carbides. Gas mixtures in the plasma nitriding, which was performed after chromizing, have a significant influence on the wear rate of the duplex treated steels. The wear and friction tests showed that the lowest friction coefficient and wear ...

DEFF Research Database (Denmark)

Zinc oxide (ZnO) and alumina (Al2O3) particles are synthesized by the combustion of their volatilized acetylacetonate precursors in a premixed air-methane flame reactor. The particles are characterized by XRD, transmission electron microscopy, scanning mobility particle sizing and by measurement of the BET specific surface area. Pure (?-)alumina particles appear as dendritic aggregates with average mobile diameter 43-93 nm consisting of partly sintered, crystalline primary particles with diameter 7.1-8.8 nm and specific surface area 184-229 m2/g. Pure zinc oxide yields compact, crystalline particles with diameter 25-40 nm and specific surface area 27-43 m2/g. The crystallite size for both oxides, estimated from the XRD line broadening, is comparable to or slightly smaller than the primary particle diameter. The specific surface area increases and the primary particle size decreases with a decreasing flame temperature and a decreasing precursor ...

Energy Technology Data Exchange (ETDEWEB)

A recent road test at LLNL underscored the zinc/air battery`s capacity to give electric vehicles some of the attractive features of gas-driven cars: a 400-km range between refueling, 10-minute refueling, and highway-safe acceleration. Developed at Lawrence Livermore National Laboratory, the battery weights only one-sixth as much as standard lead/acid batteries and occupies one-third the space, yet costs less per mile to operate. What`s more, because the battery is easily refuelable, it promises trouble-free, nearly 24-hour-a-day operation for numerous kinds of electric vehicles, from forklifts to delivery vans and possibly, one day, personal automobiles. The test of a Santa Barbara Municipal Transit bus with a hybrid of zinc/air and lead/acid batteries capped a short development period for the zinc/air battery. The test run indicated the zinc/air battery`s potential savings in vehicle weight from 5.7 to ...

International Nuclear Information System (INIS)

In this letter a method to estimate the visco-elastic response of monolithic ceramics to cyclic loading conditions at high temperatures is proposed. A relation is observed between the visco-elastic energy dissipation measured for two silicon nitride materials, and the structural characteristics of their respective intergranular phases. Some consequences for the fatigue resistance of the tested materials, and of non-transforming monolithic ceramics in general, are discussed. Two batches (G for glassy and C for crystalline) of SiAlON have been studied. The G-batch is obtained by pressureless sintering of silicon nitride powder with Y_2O_3 (6 wt%) and 6AlN-SiO_2 (5 wt%) as sintering additives. The main phase after sintering is #beta#-sialon. Upon cooling from the sintering temperature the amorphous intergranular residues of the sintering additives and of SiO_2, which is unavoidably present as a thin layer on the silicon ...

Energy Technology Data Exchange (ETDEWEB)

Nitrogen ion implantation improves the wear resistance of Ti-6Al-4V alloys by forming a hard TiN superficial passivation layer. However, the thickness of the layer formed by traditional ion implantation is typically 100-200 nm and may not be adequate for many industrial applications. We propose to use radio-frequency (RF) plasma nitriding and nitrogen plasma immersion ion implantation (PIII) to increase the layer thickness. By using a newly designed inductively coupled RF plasma source and applying a series of negative high voltage pulses to the Ti-6Al-4V samples. RF plasma nitriding and nitrogen PIII can be achieved. Our process yields a substantially thicker modified layer exhibiting more superior wear resistance characteristics, as demonstrated by data from micro-hardness testing, pin-on-disc wear testing, scanning electron microscopy (SEM), as well as Auger electron spectroscopy (AES). The performance of our newly developed inductively ...

International Nuclear Information System (INIS)

In this work we report a study of the induced changes in structure and corrosion behavior of martensitic stainless steels nitrided by plasma immersion ion implantation (PI"3) at different previous heat treatments. The samples were characterized by x-ray diffraction and glancing angle x-ray diffraction, scanning electron microscopy, energy dispersive x-ray spectroscopy, and potentiodynamic measurements. Depending on the proportion of retained austenite in the unimplanted material, different phase transformations are obtained at lower and intermediate temperatures of nitrogen implantation. At higher temperatures, the great mobility of the chromium yields CrN segregations like spots in random distribution, and the #alpha#"'-martensite is degraded to#alpha#-Fe (ferrite). The nitrided layer thickness follows a fairly linear relationship with the temperature and a parabolic law with the process time. The corrosion resistance depends strongly on ...

Science.gov (United States)

Understanding the influence of interfacial structures on the nanoarchitecture mechanical properties is of particular importance for its mechanical applications. Due to a small size of constituting nanostructural units and a consequently high volume ratio of such interfacial regions, this question becomes crucial for the overall mechanical performance. Boron nitride bamboo-like nanotubes, called hereafter boron nitride nanobamboos (BNNBs), are composed of short BN nanotubular segments with specific interfaces at the bamboo-shaped joints. In this work, the mechanical properties of such structures are investigated by using direct in situ transmission electron microscopy tensile tests and molecular dynamics simulations. The mechanical properties and deformation behaviors are correlated with the interfacial structure under atomic resolution, and a geometry strengthening effect is clearly demonstrated. Due to the interlocked joint interfacial ...

International Nuclear Information System (INIS)

Single crystal cubic boron nitride (cBN) was heteroepitaxially grown on a seed crystal of diamond under static high pressure and high temperature at 5.5GPa and 1,600--1,700 C, respectively, for 10--100 hour. A temperature gradient method was employed for the crystal growth by using lithium boron nitride as a solvent. Initial growth feature of cBN crystal was found on the diamond seed surface after the growing time of 10 minutes. The nucleation sites of the crystals seem to be near the etch pits on the diamond surface which were introduced by the surface dissolution by the solvent for cBN growth. Two types of growth features, island and step growth were typically shown on the surface. It can be seen that grown crystal appearing as a (111) nitrogen face was exhibited with the step growth feature, while the (11n) face exhibited the island growth feature. Considering the growth process under constant P-T growing condition, growth rate of cBN ...

International Nuclear Information System (INIS)

The 2-step low temperature plasma processes (the combined carburizing and post-nitriding) were carried out for improving both the surface hardness and corrosion resistance of AISI 316L stainless steel. The effects of processing time and temperature on the surface properties during nitriding step were investigated. The expanded austenite (#gamma#N)was formed on all of the treated surface. The thickness of #gamma#N was increased up to about 20 #mu#m and the thickness of entire hardened layer was determined to be about 40 #mu#m. The surface hardness reached up to 1,200 HV_0_._1 which is about 5 times higher than that of untreated sample (250 HV_0_._1). The thickness of #gamma#N and concentration of N on the surface were increased with increasing processing time and temperature. The corrosion resistance in 2-step low temperature plasma processed austenitic stainless steels was enhanced more than that in the untreated austenitic stainless steels due ...

Energy Technology Data Exchange (ETDEWEB)

The initiation and characteristics of mossy zinc electrodeposits have been investigated. Batteries with zinc electrodes are candidates for electric vehicle applications; however, this electrode is prone to form non-compact deposits that contribute to capacity loss and battery failure. Moss is deposited when the current density is far from the limiting current. This morphology first appears only after the bulk deposit is approximately 1 {mu}m thick. In this investigation, the effects of flow rate (Re=0--4000), current density (0--50 mA/cm{sup 2}), concentration of the electroactive species (0.25 and 0.5 M), and the concentration of supporting electrolyte (3, 6, and 12 M) on the initiation of moss were examined. The rotating concentric cylinder electrode was employed for most of the experiments; and a flow channel was used to study the development of morphology. After the experiment, the deposit was characterized using microscopic, x-ray ...

International Nuclear Information System (INIS)

Nano-sized zinc oxide was synthesized and deposited onto cellulosic fibers using the sol-gel process at ambient temperature. The prepared materials were characterized using several techniques including scanning electron microscopy, transmission electron microscopy, diffuse reflectance spectroscopy, X-ray diffraction and thermogravimetric analysis. X-ray diffraction studies of the ZnO-coated fiber indicate formation of the hexagonal crystal phase which was satisfactory crystallized on the fiber surface. The electron micrographs show formation of zinc oxide nanoparticles within 10-15 nm in size which have been homogeneously dispersed on the fiber surface. The prepared materials show significant photocatalytic self-cleaning activity, which was monitored by diffuse reflectance spectroscopy. The photoactivity was studied upon measuring the photodegradation of methylene blue and eosin yellowish under UV-Vis irradiation. The photocatalytic activity of ...

International Nuclear Information System (INIS)

The main aims of the study were: 1) the evaluation of iron and zinc status in women of Lodz aged 18-45 years, 2) adaptation of the whole body counter to in vivo measurements absorption of iron given to the gastro-intestinal tract of volunteers and 3) in rat model estimation iron bioavailability from fortified wheat flour combined with products usually consumed in Poland. During five months investigations thirty seven women were examined each one twice in two months interval. Following variables were measured: iron and zinc in blood serum, in public and scalp hair and in food, taste acuity score, serum ferritin, hemoglobin, total iron binding capacity, red blood cells, mean corpuscular concentration and corpuscular volume. Prevalence of iron deficiency and iron deficient anemia were assessed by two models in terms of the depression of serum ferritin and hemoglobin concentrations. 64 refs, 6 figs, 23 tabs.

Energy Technology Data Exchange (ETDEWEB)

The use of concentrated solar energy for co-producing Zn and synthesis gas from Zn O and natural gas upgrades the calorific value of the initial reactants by 39% and, when compared to the traditional carbothermic reduction of Zn O, has the potential of reducing CO{sub 2} emissions by up to 78%. An economic assessment for an industrial thermochemical plant, 30 to 51 MW solar input, indicates that the cost of solar production of zinc ranges between 89-133 $/t (excluding the cost of Zn O feed and credit for pollution abatement), and thus might be competitive with conventional fossil-fuel-based processes at current fuel prices. The cost of solar H{sub 2}, produced by splitting water with zinc, is estimated to be in the range 0.10-0.14 $/kWh, and it is a favorable long term prospect once the cost of energy will account for the environmental externalities from fossil fuel burning such as the costs for CO{sub 2} mitigation and pollution abatement. ...

International Nuclear Information System (INIS)

The effect of W and V on the high temperature strength properties of 12%Cr-15%Mn austenitic steels was studied from the view point of precipitation hardening and internal stress. The contribution of W addition to the tensile and creep-rupture strength was not so large. By contrast the combined addition of W and V increased the strength considerably. These are resulted from the precipitation of fine vanadium nitride (VN) within grains and the enhancement of M_2_3C_6 type carbide precipitation at grain boundaries. The V added material had large internal stress value which is considered to be due to dislocation movement disturbed by fine vanadium nitrides. (author).

Energy Technology Data Exchange (ETDEWEB)

In support of the efforts to apply ceramics to advanced heat engines, a study is being performed of the performance of ceramics at the ring/cylinder interface of advanced (low heat rejection) engines. The objective of the study, managed by the Oak Ridge National Laboratory, is to understand the basic mechanisms controlling the wear of ceramics and thereby identify means for applying ceramics effectively. Attempts to operate three different zirconias, silicon carbide, silicon nitride, and plasma-sprayed ceramic coatings without lubrication have not been successful because of excessive friction and high wear rates. Silicon carbide and silicon nitride perform well at ambient temperatures with fully formulated mineral oil lubrication, but are limited to temperatures of 500F because of the lack of suitable liquid lubricants for higher temperatures.

Energy Technology Data Exchange (ETDEWEB)

Ag, Cu, and Ni metallizations were inkjet printed with near vacuum deposition quality. The approach developed can be easily extended to other conductors such as Pt, Pd, Au, etc. Thick highly conducting lines of Ag and Cu demonstrating good adhesion to glass, Si, and printed circuit board (PCB) have been printed at 100-200 deg C in air and N2 respectively. Ag grids were inkjet-printed on Si solar cells and fired through the silicon nitride AR layer at 850 deg C, resulting in 8% cells. Next generation inks, including an ink that etches silicon nitride, have now been developed. Multi-layer inkjet printing of the etching ink followed by Ag ink produced contacts under milder conditions and gave solar cells with efficiencies as high as 12%.

Energy Technology Data Exchange (ETDEWEB)

We report the use of ion beam induced charge imaging to characterise the charge signal uniformity of epitaxial gallium nitride radiation detectors. The detectors were fabricated from 2 {mu}m thick semi-insulating gallium nitride, grown by MOCVD on a sapphire substrate. A carrier concentration of 1.4x10{sup 15} cm{sup -3} was measured using capacitance-voltage measurements. Ion beam induced charge imaging was carried out with a 2 MeV alpha particle beam focussed to a 3 {mu}m diameter and raster scanned across the device. The resulting ion beam images show excellent charge signal uniformity in this material with no evidence of material defects or polycrystalline structure on the micrometer length scale. No evidence of charge signal trapping was observed in these devices.

International Nuclear Information System (INIS)

Nano structured carbon nitride thin films were deposited at different RF powers in the range of 50 W to 225 W and constant gas ratio of (argon: nitrogen) Ar:N_2 by RF magnetron sputtering. The atomic percentage of Nitrogen: Carbon (N/C) content and impedance of the films increased from 14.36% to 22.31% and 9 x 10"-"1 #OMEGA# to 7 x 10"5 #OMEGA# respectively with increase in RF power. The hardness of the deposited films increased from 3.12 GPa to 13.12 GPa. The increase in sp"3 hybridized C-N sites and decrease of grain size with increase in RF power is responsible for such variation of observed mechanical and electrical properties.

International Nuclear Information System (INIS)

A survey is presented of the principles and practice of tailoring sintering liquid composition and processing cycle to enable crystallisation of intergranular phases in silicon nitride and sialon ceramics. Critical features in sialon ceramics are the O/N balance in residual glasses and post-sintering heat-treatment temperatures to enable nucleation of either intermediate phases at constant composition or oxide phases with re-partitioning of non stoichiometric components in #beta#' or #alpha#' solid solutions. Crystallisation of disilicate phases in non-sialon compositions exemplifies a problem in control of polymorphs with differing atomic volumes. Crystallisation of intergranular phases has an influence mainly on high-temperature mechanical and environmental behaviour of these ceramics. (orig.).

International Nuclear Information System (INIS)

Accurate full-potential self-consistent linearized augmented-plane-wave (FLAPW) calculations have been carried out for hexagonal boron nitride. The resulting energy-band structure indicates that this material is an indirect-gap insulator and shows the existence of two unoccupied interlayer bands, similar to those found in graphite and graphite intercalation compounds. Chemical bonding is mainly covalent, with a small charge transfer towards the nitrogen atoms. Moreover, model-potential calculations, based on first-principles FLAPW wave functions and potentials, have been used to study slabs of thickness up to 35 layers. Contrary to the case of graphite, our results do not provide evidence of surface states associated with the interlayer bands.

Energy Technology Data Exchange (ETDEWEB)

A series of modifications which increased the capacity of Canadian Electrolytic Zinc's Valleyfield plant from 220,000 MT/year to 260,000 MT/year during the last decade is discussed, combined with an an overview of the plant's operations. The modifications included modernisation of the waste disposal methods and facilities, such as a new high-density sludge wastewater treatment process, a new process to remove selenium from weak acid solutions and the jarofix process. Roasting capacity also has been improved by recent investments in new cooling coils, rebricking, oxygen enrichment and process automation. In addition to increases in refining capacity, the improvements also enabled the company to minimize its impact on the environment and the community.

British Library Electronic Table of Contents (United Kingdom)

Polycrystalline ZnO doped with Mn (5 and 10at%) was prepared by the co-precipitation method. The effect of Mn doping on the photocatalytic, antibacterial activities and the influence of doping concentration on structural, optical properties of nanoparticles were studied. Structural and optical properties of the particles elucidated that the Mn2+ ions have substituted the Zn2+ ions without changing the Wurtzite structure of ZnO. The optical spectra showed a blue shift in the absorbance spectrum with increasing dopant concentration. The photocatalytic activities of ZnO powders were evaluated by measuring the degradation of methylene blue (MB) in water under the UV region. It was found that undoped ZnO bleaches MB much faster than manganese doped ZnO upon its exposure to the U...

Energy Technology Data Exchange (ETDEWEB)

In the Carpathian Basin, significant percentage of watershed area and floodplains of rivers are utilised agriculturally. Several potential sources of poisonous metal pollution have been identified in these areas. Because of spills from some of them a few severe accidents have happened especially in the watershed area of Tisza River during the last decades. The motivation of our present work was to produce {sup 62,65}Zn and {sup 203}Pb radioisotopes because they can be used especially as tracers for studying the kinetics of uptake, transport and accumulation of zinc and lead by plants under different circumstances. (orig.)

Energy Technology Data Exchange (ETDEWEB)

The reduction of oxygen was studied in 0.1 M KCl at 70 deg. C using the rotating disk electrode (RDE) technique on platinum and electrodeposited ZnO thin film electrodes deposited on platinum substrates. In the absence of Zn{sup 2+} ions in solution, a Tafel slope of 139 mV dec{sup -1} was obtained, a value close to that measured on bare platinum electrode (133 mV dec{sup -1}) and ascribed to the limitation of the reaction rate by the first electron transfer. The main difference between the noble metal and the oxide electrode was a shift of the curves towards more negative potentials. In the presence of Zn{sup 2+} ions, the current density decreased significantly and the Tafel slope was measured at 282 mV dec{sup -1} showing that the electrode was partially blocked by zinc oxide formation reaction intermediates.

Energy Technology Data Exchange (ETDEWEB)

This paper reports the results of leaching experiments conducted with and without Thiobacillus ferroxidans at the same conditions in solution. The extent of leaching of ZnS with Bacteria is significantly higher than that without bacteria at high concentrations of ferrous ions. A porous layer of elemental sulfur is present on the surfaces of the chemically leached particles, which no sulfur is present on the surfaces of the bacterially leached particles. The analysis of the data using the shrinking-core model shows that the chemical leaching of ZnS is limited by the diffusion of ferrous ions through the sulfur product layer at high concentrations of ferrous ions. The analysis of the data shows that diffusion through the product layer does not limit the rate of dissolution when bacteria are present. This suggests that the action of T.ferroxidans in oxidizing the sulfur formed on the particle surface is to remove the barrier to diffusion by ferrous ions.

International Nuclear Information System (INIS)

A theoretical study of electron and positron band structures of zinc-blende AlN and InN and their alloy Al_0_._5In_0_._5N is presented using the first-principles full-potential linearized augmented plane-wave method. Equilibrium lattices constants are determined from the total-energy minimization method. The results are compared with previous calculations and with experimental measurement. Electron and positron charge densities are computed as function of position in the unit cell. Detailed plots of distributions are along the direction. The ionicity factors are calculated by means of three different approaches. The calculated results of the positron charge density reflect the high insight for the annihilation effect.

Energy Technology Data Exchange (ETDEWEB)

We report progress in an effort to develop and demonstrate a refuelable zinc/air battery for fleet electric vehicle applications. A refuelable module consisting of twelve bipolar cells with internal flow system has been refueled at rates of nearly 4 cells per minute refueling time of 10 minutes for a 15 kW, 55 kWh battery. The module is refueled by entrainment of 0.5-mm particles in rapidly flowing electrolyte, which delivers the particles into hoppers above each cell in a parallel-flow hydraulic circuit. The concept of user-recovery is presented as an alternative to centralized service infrastructure during market entry.

International Nuclear Information System (INIS)

The Co-ordinated Research Programme (CRP) on ''Isotope-Aided Studies on the Bioavailability of Iron and Zinc from Human Diets'' was initiated by the IAEA in 1990, and presently encompasses participating institutes in 11 countries. A summary of the discussions that took place during thr second Research Co-ordination Meeting held in Hyderabad, India, between 16-20 November 1992, is given in this report together with 12 working papers (progress reports) presented by individual participants. A separate abstract was prepared for each of these papers. Refs, figs and tabs.

Energy Technology Data Exchange (ETDEWEB)

The cyclic voltammetry indicated that the oxygen reduction reaction (ORR) proceeded by the four-electron pathway mechanism on larger Ag particles (174 nm), and that the ORR proceeded by the four-electron pathway and the two-electron pathway mechanisms on finer Ag particles (4.1 nm), simultaneously. The kinetics towards ORR was measured at a rotating disk electrode (RDE) with Ag/C electrode. The number of exchanged electrons for the ORR was found to be close to four on larger Ag particles (174 nm) and close to three on finer Ag particles (4.1 nm). The zinc-air battery with Ag/C catalysts (25.9 nm) was fabricated and examined. (author)

Energy Technology Data Exchange (ETDEWEB)

Highly water-repellent surfaces have been prepared from arrayed nanowires of zinc oxide (ZnO) by a treatment with stearic acid. The layers are electrochemically deposited on a nanocrystalline seed layer from an oxygenated aqueous zinc chloride solution. An advancing contact angle (CA) as high as 176{sup 0} is obtained with a very small hysteresis {approx}1{sup 0}. These results, supplemented by infrared spectroscopy, show that the stearic acid forms a very well-packed self-assembled monolayer. The CA measurements show a very good stability of the treated surface even when exposed to harsh conditions or long-term ambient illumination.

Energy Technology Data Exchange (ETDEWEB)

The pyrometallurgic method consisting in introduction of refining agent into the liquid cadmium has been presented. The refining agent consisting of silicon nitride, carbon dust and sodium hydroxide has been added in several portion into the liquid cadmium. Iron has been removed from the cadmium surface in the form of floating slag.

Energy Technology Data Exchange (ETDEWEB)

This book presents papers on internal combustion engines. Topics considered include the influence of partial suppression of heat rejection on performance and emissions, duothermic combustion, turbochargers made of sintered silicon nitrides, heat flux, low heat rejection engines, exhaust energy recovery, combustion chamber insulation, computerized simulation, heat transfer, friction, hoop stress effects, and bonding ceramics and metals.

International Nuclear Information System (INIS)

In this paper, we report on a comparative study of active screen plasma nitriding (ASPN) and conventional dc plasma nitriding (CPN) behavior of 30CrNiMo8 low-alloy steel that has been examined under various process conditions. The process variables included active screen setup parameters (screen and iron plate top lids placed on the screen setup with 8 mm of hole size), treatment temperature (550 and 580 deg. C), gas mixture (75/25 and 25/75 of N_2/H_2) and treatment time (5 and 10 h) in 500 Pa pressure. The structure and phases composition of the diffusion zone and compound layer were studied by X-ray diffraction (XRD), microhardness tests, light optical microscopy and scanning electron microscopy (SEM). It was observed that treated sample surfaces in both CPN and ASPN methods consist of #gamma#' and #epsilon# phases, and while the nitriding time and/or temperature increases, the intensity of #epsilon# phase in the ...

Energy Technology Data Exchange (ETDEWEB)

The growth of stoichiometric and non-stoichiometric silicon nitride films was studied experimentally on 100 mm silicon wafers by batch depositions from the dichlorosilane (SiH{sub 2}Cl{sub 2})-ammonia (NH{sub 3}) system in a hot-wall horizontal low pressure chemical vapor deposition (LPCVD) reactor. The growth kinetics were discussed in terms of the Langmuir adsorption isotherm. The kinetic parameters were determined by comparing the experimental data with a one-dimensional simulation model. The decomposition of NH{sub 3} at high temperatures was included in the simulation procedure. When the SiH{sub 2}Cl{sub 2}:NH{sub 3} ratios were greater than 1.5, a quantity higher than the thermodynamic critical values above which Si-rich nitride films begin to deposit, various SiN{sub x} films with x < 4/3 were obtained. The composition of the SiN{sub x} films was found to vary along the LPCVD reactor. The film stoichiometry was examined by Rutherford ...

International Nuclear Information System (INIS)

We report the oxygen, hydrogen, and deuterium effects on nitrogen implantation of stainless steel. Oxygen is absorbed on the surface creating a potential barrier and diminishing the nitrogen retention. Deuterium removes more oxygen from the surface than hydrogen, augmenting the nitrogen chemical potential and yielding faster nitrogen diffusion into the bulk material.

Energy Technology Data Exchange (ETDEWEB)

This investigation involves a study of the influence of key processing parameters on the heating of materials using microwave energy. Selective and localized heating characteristics of microwaves will be utilized in the sintering of ceramics without hydrostatic pressure. In addition, combustion synthesis will be studied for the production of powders, carbides, and nitrides by combining two or more solids or a solid and a gas to form new materials. The insight gained from the interaction of microwaves with various materials will be utilized in the mobilization and subsequent redeposition of uranium.

International Nuclear Information System (INIS)

TEM and HRTEM have been used to characterise the microstructures of materials formed by hot-pressing silicon nitride with an Al_2O_3-SiO_2-TiO_2 densification aid system, to form #beta#'-sialon-TiN composites in which the TiN particles are of 20-100 nm dimension. (orig.).

International Nuclear Information System (INIS)

The separation, concentration, and determination of trace elements in iron ores are described. After the sample has been dissolved, the iron is separated by liquid-liquid extraction with a liquid cation-exchanger, di-(2-ethylhexyl) phosphoric acid. The trace elements aluminium, cadmium, calcium, chromium, cobalt, copper, lead, magnesium, manganese, mercury, potassium, sodium, vanadium, and zinc are determined in the aqueous phase by atomic-absorption spectrophotometry.

Science.gov (United States)

In this study, six groups of rats were fed as follows: Groups 1 and 2 were fed formulated diets supplemented with zinc or without zinc respectively. Groups 3 and 4 were fed formulated diets supplemented with zinc plus phytic acid extracted from sweet potato (Ipomea batatas) or commercial phytic acid respectively. Groups 5 and 6 were fed formulated diets supplemented with phytic acid extract from sweet potato or commercial phytic acid respectively. The animals were fed for three weeks and then sacrificed The activities of key enzymes of carbohydrate and lipid metabolism as well as transaminases in the liver were determined. Blood glucose level was also assessed. Phytic acid extract consumption from sweet potato and commercial phytic acid plus zinc supplement lowered blood glucose levels. There was no significant change in the activity of 6-phosphogluconate dehydrogenase among the groups. Similarly, ...

Energy Technology Data Exchange (ETDEWEB)

An evaluation was made of the effectiveness of the action of reagents used for cleaning cyan-containing waste water for conditioning of the overflow of copper concentrate thickners of the Belousovskiy enrichment before sorption extraction of gold by activated charcoal. It was established that conditioning of the overflow by iron sulfates (II), copper and zinc diminshes, and by hypochlorite increases the capacitance of the activated charcoal for gold.

UK PubMed Central (United Kingdom)

Thlaspi caerulescens is a heavy metal hyperaccumulator plant species that is able to accumulate extremely high levels of zinc (Zn) and cadmium (Cd) in its shoots (30,000 μg...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

Energy storage can be a cost-effective component of hybrid remote power systems. Storage serves the special role of taking advantage of intermittent renewable power sources. Traditionally this role has been played by lead-acid batteries, which have high life-cycle costs and pose special disposal problems. Hydrogen or zinc-air storage technologies can reduce life-cycle costs and environmental impacts. Using projected data for advanced energy storage technologies, LLNL ran an optimization for a hypothetical Arctic community with a reasonable wind resource (average wind speed 8 m/s). These simulations showed the life-cycle annualized cost of the total energy system (electric plus space heating) might be reduced by nearly 40% simply by adding wind power to the diesel system. An additional 20 to 40% of the wind-diesel cost might be saved by adding hydrogen storage or zinc-air fuel cells to the system. Hydrogen produced by electrolysis of water using ...

UK PubMed Central (United Kingdom)

Cadmium (Cd) exposure causes glucosuria (glucose in the urine). Previously, it was shown that Cd exposure of primary cultures of mouse kidney cells (PMKC) decreased mRNA levels of the glucose...Full Text Available

Energy Technology Data Exchange (ETDEWEB)

In the present work the effect of different surface conditions on plasma nitriding response of AISI M2 high speed steel was investigated. The plasma nitriding of ground and sandblasted samples and drills was performed at temperatures of 400 C and 500 C for two gas mixtures: 5 vol.% N{sub 2} and 76 vol.% N{sub 2} in hydrogen. Surface layers were characterized before and after plasma nitriding concerning the microstructure, roughness, microhardness, chemical composition, phase composition and residual stress states. Machining tests were carried out with drills during which drilling forces and flank wear have been measured. A significant effect of the surface state prior to nitriding on residual stress states and the properties of the nitrided layer and untreated core has been observed. Thinner nitrided layers on ground and sandblasted samples were attributed to ...

International Nuclear Information System (INIS)

Carbothermal reduction-nitridation (CRN) of SiO_2 is an attractive method for manufacturing Si_3N_4 powders with controlled grain morphology. Moreover, #beta#-sialon powders could also be synthesized from either pure powder mixtures or some inexpensive raw minerals by CRN. The resultant powders have shown some advantages, especially in manufacturing sialon products at low cost. However, there have been only a few works on preparing #alpha#-sialon powders. In this work, Ca-#alpha# sialon powder was synthesized by CRN of a SiO_2-Al_2O_3 and CaCO_3 powder mixture An unusual morphology of hollow balls of 200 to 500nm with many nano size #alpha#-sialon particles of 10 to 30nm was identified from the resultant Ca-#alpha# sialon powders. This has never been previously reported for sialon ceramics. It was consequently confirmed that the morphologies of the products were clearly related to the intermediate products appearing during CRN reaction. Copyright (2000) The ...

Energy Technology Data Exchange (ETDEWEB)

By using a plasma nitriding procedure at the PUPR Mirror Cusp Plasma machine, surface hardness is increased in 302/304-type stainless steel samples by exposing them to high-ion-density plasma at high vacuum. This method successfully dopes the surface of the material with strengthening nitrogen ions, without the use of chemical procedures that sacrifice the resistance to corrosion of the given material. A 500 V negative bias is placed on the sample exposed to the nitrogen plasma, where high-energy ions are therefore attracted and immersed into the metallic matrix microns into the surface of the stainless steel. This potential maintains a constant surface temperature at approximately 800 deg. C. The plasma parameters including ion density and plasma temperature were diagnosed using single Langmuir probes. The stainless steel samples were then tested using scanning electron microscopy (SEM), and Vickers micro-hardness testing to determine the increment in the surface ...

International Nuclear Information System (INIS)

Synthesis of Eu-doped #beta#- and 15R-SiAlONs was studied by the ammonia nitridation of precursors derived from an #alpha#-Si_3N_4 fine powder dispersed in aluminum glycine gel with various Si/Al ratio and post-annealing in a nitrogen pressure furnace. The largest amount of #beta#-SiAlON was observed in the product at 1750 deg. C for Si/Al = 1/1 with small amounts of both #alpha#- and 15R-SiAlON impurities. The product showed two emissions at around 420 nm and 560 nm. The emission intensities decreased with increasing amount of #beta#-SiAlON. The former and latter emissions were assigned to Eu"2"+ in the 15R- and #alpha#-SiAlONs impurities. A mixture of Eu-doped 15R-SiAlON with #alpha#-Al_2O_3 impurity was obtained for Si/Al = 1/6, using AlN together with Al(NO_3)_3.9H_2O in a 2/1 atomic ratio as the aluminum source. It showed a bluish-white emission at 450 nm under 254 nm radiation.

Energy Technology Data Exchange (ETDEWEB)

Aiming to realize ball bearings operable in a vacuum and under high temperature, silicon nitride (Si3N4) ceramic ball bearings were tested. The tested ball bearings were angular contact ball bearings composed of silicon nitride with sputtered molybdenum disulfide coating using a retainer of hot-pressed self-lubricating composite material. The time variation of the frictional torque was examined for the operations under the conditions at 500{degree}C in a vacuum at a rotational speed of 600 rpm and 50N thrust load for 5{times}10{sup 7}revolutions (1400 hours) and for 1.5{times}10{sup 8}revolutions (4200 hours). Excellent tribological performance was obtained. The ball bearings are lubricated with the molybdenum disulfide film at the initial stage of the operation and with a transfer film formed from the retainer material to the balls. In a test at 650{degree}C, low and stable frictional torque was observed up to 500 hours of operation as of the ...

Energy Technology Data Exchange (ETDEWEB)

An extruder used by kneading stearic acid (St acid) into it for the production of polystyrene for injection molding was studied. Most disadvantageous of kneading methods, melt-feed method, was applied because this method enables the utilization of existing facilities. St acid is discolored when the temperature surpasses 270{sup 0}C in nitrogen atmosphere, and the contact with metals intensifies the discoloring. The discoloring is more intensified by the contact with nitriding steel than with stainless steel. Residence time is 85 seconds, and even the contact with nitriding steel does not discolor ST acid when the temperature is lower than 270{sup 0}C. In the melt-feed method, when the die is in a bad shape, it brings about dead space at the tip of the die and St acid holds up there. When the kneading is in bad condition (St acid and polymer are hard to mix because their viscosities are quite different), St acid gathers between the barrel wall ...