bluuebunny/crossref_metadata_2025 huggingface dataset:
Electrothermal analysis as a tool for Designing Electric Detonator Firing Circuits
Authors: Austing J. L. , Tulis A. J. , Schmitt H. R. , Urbanski E. , Mosora J. A. , Hawley J.
Published: December 2004

The use of modified forms of the Rosenthal electrothermal equation to aid in the design of a capacitor discharge firing circuit for a specific detonator is described. The electrothermal parameters Cp and γ, representing the heat capacity of the bridge and the heat loss factor, respectively, were calculated from previously obtained firing data for the detonator. These calculations provided input to the design of a firing circuit utilizing electrolytic capacitors, which have a large value of electrical capacity but also a non‐negligible internal resistance. Calculations were performed which (1) revealed the degrading effect on detonator initiation caused by too large a value of internal resistance, and (2) permitted selection of a particular capacitor that would allow reliable functioning of the detonator with initiation times of about 230 μs. The circuit was designed utilizing this capacitor, and in the experimental evaluation of the circuit the measured initiation times were compared with the calculated values. Good agreement between the two was documented, and the conclusion was reached that the detonator functioned reliably. The merits of the electrothermal analysis and the assumptions utilized therein relative to a vigorous heat transfer/reaction kinetics modeling of the flow of energy from the bridge into the explosive flash charge are discussed in detail.
Experiments of Initiation of Covered, but Unconfined High Explosive Charges by means of shaped charge jets
Authors: Held M.
Published: December 2004

Experiments on the initiation of high explosive charges in contact with a barrier or separated from it by a 15 mm air gap or a 2 mm acrylic glass layer have been performed utilising a simultaneous framing and streak camera. With increasing barrier thickness the shaped charge jet is increasingly consumed.
Temperature Change of Light Induced Explosion of explosive material
Authors: Leu An‐Lu , Yen Chen‐Shyong
Published: December 2004

A theoretical analysis based on the adiabatic consideration of one‐ dimensional model for initiation of explosive materials by intense light is performed. An expression is obtained which can be used to calculate the explosion temperature.
Materials Science and Environmental Qualification applied on solid chemical energetics
Authors: Geißler A. , Schmitt D. , Ziegahn K.‐F.
Published: December 2004

In the environmental qualification of chemical energetics, influences from the environment occurring in production, logistics and applications are simulated. The attempt was thus made to demonstrate or, respectively, to estimate the manipulation safety, functional behaviour and life time of energetic materials. It is here the usual method to intensify simulated environmental influences for the purpose of accelerating tests. In this paper the example of mechanical load simulation is used to demonstrate how knowledge of the behaviour of the material is necessary for an ingenious modelling and a rational increasing of test levels. Apart from the microscopic and macroscopic point of view, especially the so called “micromorphological” observation level is well suited to this purpose.
Strain Distribution in the Uniaxial Tensile Test up to High Strain Rates
Authors: Eisereich N. , Fabry C. , Fischer R. , Geißler A. , Kugler H. P. , Sinn F.
Published: December 2004

In the uniaxial tensile test forces, longitutional and transversal elongation must be measured simultaneously. Recently(1) we presented a non intrusive method to measure both elongations in one experiment. To get more information about the material behaviour beyond the yield stress we modified this test equipment. Now we obtain the strain distribution along the whole sample.
Fick's First Law Correction by an exact solution of the boltzmann equation
Authors: Straub D. , Graue R. , Heitmeir F. , Nebendahl P. , Wurst Th. K.
Published: December 2004

It is shown that there exists a dominant solution of the Boltzmann equation for an artificial model gas in terms of a relation for the diffusion flux differing from the regular formulation of Fick's first law. Its mathematical structure corresponds to the Cattaneo‐formulation based on heuristics of the Fourier heat flux vector. This dominant solution allows a realistic estimation of a diffusion relaxation time and serves as the basis for valuable information concerning two actual problems of hypersonic gas dynamics: first, a useful relation for the calculation of collision integrals for diffusion coefficients, especially at high temperatures; second, a new type of a chemical reaction equation, which is particularly relevant in very fast relaxation processes encountered in the chemistry of fuels.
Organic Fillers for Smokeless Insulations of Double‐Base Propellants
Authors: Pröbster M.
Published: December 2004

The number of organic fillers for smokeless polyurethan‐insulations hitherto known is rather small. In this paper two general formulae, expanding the range of organic fillers, are described. The first formula describes molecules with linear structures, the second one those with cyclic structures. A common feature of the fillers mentioned above their high (N + O)/C ratio.
Ignition Time Delay of polyacrylic fuels‐ammonium perchlorate condensed mixtures
Authors: Girdhar H. L. , Peerzada G. M.
Published: December 2004

Ignition time delay of condensed mixtures containing various polyacrylic fuels and NH4ClO4 were measured using hot‐plate technique at several temperatures. The adiabatic theory of explosion assuming condensed phase exothermic reactions was used to evaluate the activation energy of ignition. Activation energy of ignition has been found to be dependent on the decomposition characteristic of the fuel component.
Design and Performance Evaluation of Flat Cone Charge
Authors: Roy P. K. , Rao K. Rama
Published: December 2004

The performance of flat cone charge cannot be calculated by the well known hydrodynamic equations used for conventional hollow charges. As such, experimental studies have been carried out to evaluate the effects of liner cone angle, liner thickness, explosive charge to liner mass ratio and stand‐off on the penetration performance. Generalized equations are established relating the basic parameters with the performance of flat cone charge. A simplified computerized design approach has been suggested which would be useful to the practical weapon designers.
Combustion mechanism of HMX
Authors: Kubota Naminosuke , Sakamoto Satoshi
Published: December 2004

The combustion wave structure and thermal decomposition process of HMX were examined in order to elucidate the burning rate characteristics of HMX. The combustion wave can be divided into three zones: nonreactive solid‐phase, surface reaction, and gas‐phase reaction zones. Measurements with micro‐thermocouples revealed that the heat flux produced in the surface reaction zone is approximately equal to the heat flux transferred back from the gas phase to the burning surface. Accordingly, the reaction process in the suface reaction and the gas phase zones plays a dominant role in the burning rate of HMX. The gas phase reaction zone consists of a two‐stage reaction process: the first stage is the exothermic rapid reaction process between NO2 and aldchydes, and the second stage is the exothermic slow reaction process between NO and N2O and remaining fuel species. The luminous flame zone which is determined to be the second stage reaction process approaches rapidly the burning surface as pressure increases. However, the luminous flame reaction appears to be little responsible for the burning rate of HMX.

Examinations of the quenched burning surface of HMX samples revealed that the burning surface melts and forms a noncrystallized intermediate material. The surface structure appears to be different from the structure of thermally degraded HMX samples which were obtained by a thermogravnmetric analysis.
Studies on Thermal Decomposition of Energetic Nitrourea Salts
Authors: Heming Xiao , Jinhua Yuan , Xinquan Xin , Anbang Dai
Published: December 2004

Thermal decomposition of nitrourea salts (K, Na, Ag, Ba) was studied in hydrogen atmosphere, helium atmosphere and vacuum by gas chromatography and mass spectrometry. The evolution of dinitrogen oxide, water, hydrazine, nitrogen dioxide and the formation of cyanate salts during thermodecomposition of nitrourea salts in helium and hydrogen were confirmed. In vacuum the evolved gaseous products changed to dinitrogen oxide, water, nitrogen monoxide, nitrogen gas indicating that interreaction between evolved gaseous products occurred. The same solid products – cyanate salts – are formed showing vacuum having no effects upon the decomposition mechanism.
Explosive‐Binder Adhesion and Dewetting in nitramine‐filled energetic materials
Authors: Bellerby J. M. , Kiriratnikom Ch.
Published: December 2004

The problems associated with poor explosive‐binder adhesion in nitramine‐filled energetic materials are reviewed. The phenomenon of dewetting and its consequences are discussed and a survey of the literature relating to specific adhesion promoters for RDX‐filled systems is presented.
Manometric Stability Tests of Double‐Base Propellants in vacuum, air, and oxygen
Authors: Havránková E. , Pilná B.
Published: December 2004

The decomposition process of several types of double‐base propellants before and after artificial aging at 75 °C for 20 days was measured in vacuum, air, and oxygen. The results are confronted with those of the test at 100 °C and with the stabilizer content before and after aging. Effects of the sample surface area were also considered.
Calorimetric determination of the heat and products of detonation of an Unusual CHNOFS Explosive
Authors: Ornellas D. L.
Published: December 2004

The heat of detonation of an explosive is determined by its chemical structure and the nature of the products that are formed during detonation. Most explosives contain the elements CHNO and, because plastic bonded explosives often include stable halocarbon polymers, the elements fluorine and/or chlorine may also be present. However, little is known about the effect of the combination of fluorine and sulfur on heat of detonation, specifically the SF5 group. Detonation calorimetry was the experimental technique used to determine the heat and very unusual products of detonation of tris‐(fluorodinitroethyl) pentafluorothio ethylorthocarbonate.
Propellant Gas Phase Chemical Kinetics
Authors: Sheshadri T. S. , Jain V. K.
Published: December 2004

An adiabatic constant pressure chemical kinetic study of the AP gas phase is conducted. The objective is to examine the importance of chemical kinetic studies for propellant deflagration modelling in general and for AP in particular. A reaction mechanism consisting of ninety five elementary reactions involving twenty one chemical species is developed to represent the AP gas phase. An important parameter that can be obtained from the kinetics is the time rate of change of temperature of the gas phase at the condensed phase‐gas phase boundary (dT/dt at t = 0). This is directly related to the heat feedback from the gas phase to the condensed phase. Comparison with earlier work indicates that the use of a one‐step overall reaction could lead to underestimates of heat feedback from the gas phase by a factor of about four. In addition it is found that the rate of decrease of dT/dt at t = 0, with pressure is much larger at lower pressures, suggesting a possible gas phase role in the low pressure deflagration limit. Further, the kinetic study does not support the conclusion of a constant fraction of AP reacting in the condensed phase in the pressure range 20–100 atmospheres. These results are at variance with what is obtained by use of a one‐step overall reaction. Thus, the one‐step overall reaction cannot represent even qualitatively several gas phase characteristics important for deflagration studies, and its use leads to erroneous results. It is concluded that a full reaction mechanism representation of gas phase chemical kinetics is essential to AP deflagration modelling. The same conclusion is probably valid for propellant deflagration modelling in general.
Inhibition Reaction of SrCO3 on the burning rate of ammonium perchlorate propellants
Authors: Miyata Kohsei , Kubota Naminosuke
Published: December 2004

The buring rate of ammonium perchlorate (AP) composite propellants is decreased significantly by the addition of SrCO3 without increasing the pressure exponent of burning rate. Results of microthermocouple measurements indicate that the burning surface temperature is increased from 700 K to 970 K by the addition of SrCO3, although the heat release rate in the gas phase is remained unchanged. DTA (differential thermal analysis) and TG (thermogravimetry) experiments were also carried out in order to determine the role of SrCO3 in the decomposition process of AP. The AP decomposition temperature is increased from 590 K to 620 K by the addition of SrCO3. The results of analysis show that the reduction of the burning rate is caused by the increased AP decomposition temperature.
Carbon resistor gauges for measuring shock and detonation pressures. II. Detonation pressure of carbohydrate‐metal composite explosives
Authors: Tulis Allen J. , Austing James L. , Baker Douglas E. , Hrdina Donald J.
Published: December 2004

An estimate of the detonation pressure of carbohydrate‐metal composite explosives has been obtained experimentally by use of carbon resistor pressure gauges mounted in the wall of the confining tubes. The composite explosives were formulated from a pharmaceutical mixture of 10/90 nitroglyccrin/ß‐lactose by weight, and was rendered detonable by inclusion of flaked aluminum and both flaked aluminum and ammonium perchlorate. The detonation pressure of the nitroglyccrin/ß‐lactose mixture with 10 percent aluminum by weight was approximatcly 1.1 GPa. The incorporation of 30 percent ball‐milled ammonium perchlorate to this formnlation increased the detonation pressure to 12.2 GPa. These pressures must be considered as estimates of the true detonation pressure, because of (a) the suspected non‐ideality of the detonation state of these explosives, (b) the statistical nature of the response of the gauges, and (c) possible inconsistencies in the interpreatation of the gauge records. It is recommended that a number of gauges be used in a given experiment, and the results be averaged as one means of cireumventing the above difficulties.
The thermal stability of the polymorphs of hexanitrohexaazaisowurtzitane, Part I
Authors: Foltz M. Frances , Coon Clifford L. , Garcia Frank , Nichols Albert L.
Published: December 2004

Phase transitions in the α‐, β‐, γ‐, and ϵ‐polymorphs of 2,4,6,8,10,12‐hexanitrohexaazaisowurtzitane (HNIW) have been studied as a function of temperature. Described are the results of high temperature equilibrium solvation studies coupled with Fourier transform infrared spectroscopy (FTIR) for the identification of polymorphic conversion. These results are augmented by data in Part II from differential scanning calorimetry (DSC), differential thermal analysis/thermogravimetric analysis (DTA/TGA), and optical hot stage microscopy(6). The thermodynamic stability order of ϵ > γ > α‐hydrate > β is shown, with the epsilon polymorph the most thermodynamically stable phase of HNTW at room temperature. The existence of multiple α‐hydrate phases is shown to complicate the determination of the equilibrium P‐T phase diagram of HNIW.
Computer‐Assisted Prediction of Novel Target High‐Energy Compounds
Authors: Pivina Tatyana S. , Shcherbukhin Vladimir V. , Molchanova Marina S. , Zefirov Nikolai S.
Published: December 2004

A methodology of predicting novel target high‐energy compounds has been developed. A formalized approach to computer generation of structural isomers starting from previous optimized gross formula has been elaborated on the joined basis of the graph theory, molecular crystal structure modeling methods and quantum chemistry calculations. Chemical structures are generated as graphs which are subsequently converted to 3D representations. Then, some physical and chemical properties are calculated to evaluate the suitability of the generated compounds for practical purposes.

Predictive capacity of this approach was demonstrated during the computer generation of new caged compounds structure with high energy content.
Increased Concentration of the Nitromethyl Aci‐Anion in nitromethane‐amine mixtures
Authors: Constantinou Constantinos P. , Pereira Carl , Chaudhri M. Munawar
Published: December 2004

We have investigated the concentration of the nitromethyl aci‐anion in nitromethane and nitromethane‐diethylenetriamine mixtures. Ultra‐violet absorption spectroscopy and electrical conductivity measurements have given direct experimental evidence that the aci‐anion concentration is increased as compared to that in pure nitromethane. The increase is consistent with a shift in the acid‐base equilibrium. In any one mixture that is in contact with air, we have also observed a subsequent decrease in the aci‐anion concentration as a function of time. A newly observed band in the vibrational spectrum of nitromethane has been assigned to the aci‐anion and was used to confirm the decrease in its concentration with time. We discuss the previously suggested link between the aci‐anion and the sensitivity of nitromethane and conclude that it is unlikely that there exists any correlation.
Formation of Nitroform in the Nitration of Gem‐Dinitro Compounds
Authors: Langlet Abraham , Latypov Nikolaj V. , Wellmar Ulf , Goede Patrick , Bergman Jan
Published: December 2004

Nitration of 4,6‐dihydroxypyrimidine in sulphuric acid gave nitroform as the sole product. This behaviour was tentatively explained by the formation of an intermediate, 5,5‐dinitro‐4,6‐dihydroxypyrimidine, that underwent hydrolysis in the nitrating acid to gem‐dinitroacetyl formamidine. This compound was further nitrated in the same reaction mixture to trinitroacetylformamidine which finally underwent hydrolytic cleavage to nitroform. It was also demonstrated that gem‐dinitroacetyl ureas were able to produce nitroform on nitration. The structures of the proposed trinitroacetylureas were confirmed by the isolation of one of their derivatives.
1,4‐Bis‐[1‐Methyltetrazol‐5‐yl]‐1,4‐Dimethyl‐2‐Tetrazene: A Stable, Highly Energetic Hexamer of Diazomethane (CH2N2)6
Authors: Klapötke Thomas M. , Mayer Peter , Schulz Axel , Weigand Jan J.
Published: December 2004

1,4‐bis‐[1‐methyltetrazol‐5‐yl]‐1,4‐dimethyl‐2‐tetrazene a formal hexamer of diazomethane can be viewed as a new stable high energy density material (HEDM) with the properties necessary for a potential green chemistry gas generator. The physical properties of the new tetrazene were determined by drop hammer and combined IR and MS pyrolysis experiments. The structure and bonding are discussed on the basis of X‐ray, MO and NBO analysis.
Reproducibility across Microwave Instruments: First Example of Genuine Parallel Scale up of Compounds under Microwave Irradiation
Authors: Alcázar Jesús , Diels Gaston , Schoentjes Bruno
Published: December 2004

One of the major issues associated to microwave assisted organic chemistry is reproducibility. In the present article we demonstrate that reproducibility of results can be obtained from commercially available single‐mode and multimode microwave reactors. In order to make an appropriate comparison of results obtained in both systems, alkylation reactions were used as a model. Based on the reproducibility observed in these experiments, parallel scale up of compounds in one irradiation experiment is reported for the first time.
A Valuable Synthesis of Reduced Peptide Bond by Microwave Irradiation
Authors: Santagada Vincenzo , Frecentese Francesco , Fiorino Ferdinando , Cirillo Donatella , Perissutti Elisa , Severino Beatrice , Terracciano Sara , Caliendo Giuseppe
Published: December 2004

Methyleneamine is a reduced form of the amide bond. The CH2NH group may be a useful tool for delineating important hydrogen‐bonding points and may also offer a general strategy for the production of enzyme resistance and potent competitive antagonists. This paper describes a facile synthesis of the CH2NH group by application of microwave energy. Moreover the importance of sterically hindered amino acids as well as the electronic effects of the side chain, in the synthesis of the hydroxamate and in the reductive alkylation steps, are evaluated. Room temperature, conventional heating and microwave irradiation of the reactions are compared. Synthesis by microwave irradiation gave the desired compound in higher yields and in shorter reaction times than those obtained at room temperature.
The Application of Microwaves in Combinatorial and High‐Throughput Synthesis as New Synthetic Procedure in Drug Discovery
Authors: Santagada V. , Frecentese F. , Perissutti E. , Favretto L. , Caliendo G.
Published: December 2004

Heterocyclic compounds hold a special place among pharmaceutically important natural and synthetic materials. The remarkable ability of heterocyclic nuclei to serve both as biomimetics and reactive pharmacophores has largely contributed to their unique value as traditional key elements of numerous drugs. In both lead identification and optimization processes there is an acute need for new organic small molecules. Traditional methods of organic synthesis are orders of magnitude too slow to satisfy the demand for these compounds; so, the fields of combinatorial and automated medicinal chemistry have been developed to meet the increasing requirement of new compounds for drug discovery; within these fields, speed is of the essence. The efficiency of microwave chemistry in dramatically reducing reaction times (reduced from days and hours to minutes and seconds) has recently been proven in several different fields of organic chemistry. We believe that the time saved by using focused microwaves is potentially important in traditional organic synthesis but could be of even greater importance in high‐speed combinatorial and medicinal chemistry.
Rapid Microwave‐Promoted Cross‐Coupling Reaction of Aryl Bromides with Aryl Boronic Acids and Sodium Tetraphenylborate Catalyzed by a Reusable Polymer‐Supported Palladium Complex
Authors: Bai Lin , Zhang Yumei , Wang Jin‐Xian
Published: December 2004

A variety of biaryls were prepared in a rapid and highly efficient manner via the cross‐coupling reaction of aryl bromides with aryl boronic acids or sodium tetraphenylborate in toluene, aqueous potassium carbonate and in the presence of a polymer‐supported palladium(II) catalyst under microwave irradiation condition. The supported catalyst was prepared directly from a commercial Merrifield resin and ultrasound dramatically accelerated the preparation of the catalyst. The polymeric catalyst can be easily separated from a reaction mixture and reused five times without decrease in activity. This suggests that a comparatively stable palladium phosphine complex is the reacting species in this special case. The reaction can be performed equally well using microwave and conventional heating, showing that microwave irradiation accelerates the reaction tremendously and in higher yields.
Microwave‐assisted Synthesis of Di‐ and trisubstituted Ureas from Thiophenoxy Carbamate Resins
Authors: Martinez‐Teipel Blanca , Green Rosalyn C. , Dolle Roland E.
Published: December 2004

The microwave‐assisted, parallel synthesis of di‐ and trisubstituted ureas is described. Microwave irradiation provides a significant rate enhancement to the in situ thermolytic cleavage of isocyanates from polymer‐supported carbamates. The method is amenable to library production and the target ureas are generally obtained in good purities (>80%).
Secondary ion mass spectrometry at close to single‐atom concentration using DC accelerators
Authors: Purser K. H. , Litherland A. E. , Rucklidge J. C.
Published: December 2004

Experiments have been conducted which show that secondary ion mass spectrometry (SIMS), together with the addition of a rather low voltage (2 MV) DC accelerator, can become an extremely powerful new technique in many fields of research related to the characterization of surface and bulk solids and with high spatial resolution. The technology is available today to build an instrument that would have high lateral resolution (∼ 1 μm) coupled with a secondary ion transmission coefficient from target to detector >10% with no mass interferences from molecular ions. Molecular ions can be fragmented and analyzed separately. We believe that this combination of secondary ion mass spectrometers and accelerators represents a most significant advance in analytical techniques.
XPS–ISS analysis of Al/Ni alloys
Authors: Storp S. , Berresheim K. , Wilmers M.
Published: December 2004

The change in the surface composition of an Al/Ni alloy (50% by weight Ni) on heating in O2 and treatment in diluted NaOH was investigated by quasi‐simultaneous XPS–ISS measurements, using a hemispherical condenser analyser both for ESCA and ISS. The oxidizing experiments were carried out in a valveless, integrated, high pressure, high temperature preparation lock.
X‐Ray photoelectron spectroscopic study of the aqueous oxidation of stellite‐6 alloy
Authors: McIntyre N. S. , Zetaruk D. , Murphy E. V.
Published: December 2004

The aqueous oxidation of the cobalt allow Stellite‐6 has been studied in pH 10 water 285°C, as a function of dissolved oxygen concentration and length of exposure time. The result surface films were analysed by X‐ray photoelectron spectroscopy (XPS) and other techniques. Using XPS, a quantitative measurement of the oxide and metallic surface components was obtained and depth‐concentration profiles were determined. The effect of gaseous oxidation on the surface composition was also studied, and from a comparison of the oxidation behaviour under aqueous and gas phase conditions, solid state and solution‐transport processes could be distinguished. The gas phase studies showed that cobalt ions diffuse preferentially to the outer surface. During aqueous oxidation, however, the surface composition is found to be depleted in cobalt; preferential dissolution of the cobalt component of the alloy is therefore occurring under these aqueous conditions.
A versatile time‐of‐flight atom probe for metallurgical applications
Authors: Miller M. K. , Beaven P. A. , Smith G. D. W.
Published: December 2004

A computer‐controlled atom prove time‐of‐flight mass spectrometer system is described which permits quantitative microanalysis to be undertaken at the 1–2 nm level. Distinctive features of the system include the use of a Johnston detector, to give low noise, high gain and high detection efficiency; incorporation of a movable channel plate and screen assembly, to provide a variable aperture; and the development of a comprehensive set of computer plate and screen assembly, to provide a variable aperture; and the development of a comprehensive set of computer software, to assist in the processing of data and presentation of analytical results. The system has been used successfully in a number of metallurgical investigations. In this paper, particular attention is given to describing the operating conditions required to achieve optimum performances, and to discussing the questions of background noise reduction and the deconvolution of spectra. The quantitative analysis capability of the instrument is demonstrated by reference to the results obtained from a range of standard materials, including steels. Applications to problems of metallurgical interest are illustrated by the analysis of ultra‐fine particles in a Cu/Co alloy, and the analysis of carbides and carbide‐matrix interfaces in a 2¼Cr/1Mo steel. The spatial resolution obtainable under different operating conditions is discussed, and the particular problems involved in the study of interfaces by this technique are described in detail.
Surface and interface analysis in polymer technology: A review
Authors: Holm R. , Storp S.
Published: December 2004

Surface analysis methods like ESCA, AES, SIMS and ISS can provide valuable information on the structure and composition of polymer surfaces. Examples of application are the investigation of surface changes, such as the effects of weathering, etching and corona treatments, and the detection of surface deposits consisting of materials like antistatic agents, lubricants and exuded constituents. Because of their high surface sensitivity and ability to differentiate between surface and bulk phenomena, surface analysis methods are particularly suitable for the investigation of interfaces between polymers and metals, glass fibres, etc., e.g. in radial tyres, cable insulations and capacitor foils. It is pointed out that in these cases the inadequacies of the preparation methods limit the value of the analytical findings more than the inadequacies of the analysis methods.
Quantitative aspects of ion scattering spectroscopy
Authors: Haeussler E. N.
Published: December 2004

Ion scattering spectroscopy (ISS) shows up some important advantages compared to other surface analytical techniques. Because of its monolayer sensitivity and the negligible matrix effects, ISS is superior in depth profiling. Isolating materials such as glass or organic compounds can be analysed without any charging problem. Because of these advantages, interest in ISS has increased in recent years and has stimulated investigations into quantitative analysis. Although most scattering phenomena, which will be discussed, are well understood, some problems remain. To overcome these problems empirical calibration methods have been developed.
Examination of elemental nonuniformities in laser surface melted ternary copper alloys
Authors: Draper C. W. , Sharma S. P. , Yeh J. L. , Bernasek S. L.
Published: December 2004

The enhanced corrosion resistance of laser melted surfaces is often rationalized from the viewpoint of the homogenizing nature of the rapid quench from the liquid. We utilize Auger spectroscopy to examine elemental nonuniformities in laser surface melted ternary copper alloys (CDA‐614 and CDA‐725). In both systems we find depletion of the highest vapor pressure element from the central area of laser melt stripes, that region which reaches the highest temperature and remains molten for the greatest period of time. Although this near surface depletion is a small effect relative to the homogenization taking place over the orders of 10 and 102 µm, it may be a significant effect which should be taken into account when explaining changes in corrosion and oxidation behavior.
The reaction of NiO and α‐Al2O3 studied by Rutherford backscattering
Authors: De Roos G. , Fluit J. M. , De Wit J. H. W. , Geus J. W.
Published: December 2004

The interfacial reaction of NiO and α‐Al2O3 to NiAl2O4 is investigated by means of Rutherford backscattering spectrometry (RBS) using 2.95 MeV He+ ions. The NiO is obtained by oxidation at 800°C of a nickel film vapour deposited on to alumina substrates. The reaction of NiO and Al2O3 does not proceed markedly at 800°C. At ∼ 1100°C, the reaction to stoichiometric NiAl2O4 is found to be followed by a slower process leading to a spinel of the non‐stoichiometric composition NiAl2O4 · xAl2O3. At ∼ 1100°C, a marked volatilization of NiO is noted. At ∼ 1000°C the reaction also proceeds at a noticeable rate. However, at this temperature the diffusion process stops at the stoichiometric spinel composition. No volatilization of NiO is observed.
Depth resolution factor of a static gaussian ion beam
Authors: Malherbe J. B. , Sanz J. M. , Hofmann S.
Published: December 2004

The dependence of the depth resolution on the contribution of a Gaussian crater shape and the finite width of a Gaussian excitation beam (and/or Gaussian acceptance function) is considered. The results show that for Auger electron spectroscopy depth profiling, the contribution of the beam shapes to the depth resolution can, in most cases, be neglected. With X‐ray photoelectron spectroscopy and secondary ion mass spectroscopy depth profiling, care has to be taken to obtain a well resolved depth profile.
ESCA studies of Ni‐25 At% Fe alloy. 2—dissolution and passivation
Authors: Marcus P. , Olefjord I.
Published: December 2004

The surface compositions of a Ni‐25 at% Fe single crystal (100) and (110) were analysed by ESCA with respect to the electrochemical behaviour in 0.05 M H2SO4 (anodic dissolution and passivation). When the alloy surface is exposed to the electrolyte solution, or anodically polarized in the active region (anodic dissolution), iron is selectively dissolved and the surface is enriched with nickel. A stationary surface composition is attained which does not depend on the polarization potential or dissolution current. Once the stable surface composition is attained, the anodic dissolution of nickel and iron takes place with the same ratio as in the alloy. The extent of the surface enrichment with nickel, calculated from a layer by layer model for XPS signal intensities is found to be almost one monolayer of nickel at the alloy surface, each following plane in depth having the same composition as the bulk (Ni3Fe). The passive film is enriched with nickel. It consists or an inner layer of nickel oxide (NiO) and an outer layer of nickel and iron hydroxides. The thickness of the passive film is 8–10 Å. The alloy/oxide interface is also enriched with Ni in its metallic state.
Basic assumptions and recent developments in quantitative XPS
Authors: Carlson T. A.
Published: December 2004

A review is made of the basic assumptions used in quantitative XPS. Particular attention is paid to problems of electron shake up and shake off, and to the angular distribution of ejected photoelectrons. Following this review, the interaction of XPS with other surface analyses is discussed and illustrated for UPS, ISS, and photon‐induced AES. The paper is concluded with a discussion of the future possible uses and advantages of synchrotron radiation for XPS including the development of XPS for microprobe analysis.
Proposition of an algorithm for calculating the surface composition from auger electron intensities
Authors: Jabłolński Aleksander
Published: December 2004

Following the practice of electron probe microanalysis, a universal computer program is proposed which calculates the surface composition of binary alloys from the measured Auger electron intensities. The program can be applied for the usual experimental procedures, i.e. the relative sensitivity factor approach, and the direct comparison with a standard. The calculations are made for two models of the surface region; firstly, a uniform composition within the sampling depth of Auger electrons, and secondly, surface enrichment limited to the first monolayer. The relation of the Auger electron intensity to the surface concentration is expressed in terms of three matrix dependent correcting factors; the backscattering factor, the inelastic mean free path and the total number of atoms in a unit volume. The backscattering factor is assumed to vary linearly with the mass fraction of a given element in the bulk. The corrections for inelastic mean free path and number of atoms per unit volume are calculated for the bulk composition or the surface composition depending on the model of the surface region. The EXTENDED FORTRAN program, in addition to calculating the surface composition, has other auxiliary facilities such as plotting the calculated results, and calculating the extent of surface segregation when the model of monolayer enrichment is not valid.
Quantitative comparison of direct and derivative AES with XPS of metal sulfides
Authors: Griffis Dieter P. , Linton Richard W.
Published: December 2004

Integral area measurements of Auger intensities for various metal sulfides give comparable quantitative results to those obtained from derivative peak‐to‐peak heights. Highest precisions for sulfur sensitivity factors were obtained by: (a) intensity measurements involving integration of background‐subtracted N(E) lineshapes, (b) matrix corrections for electron mean free path and backscattering factor, (c) the use of XPS‐derived surface stoichiometries rather than assumed bulk stoichiometries for the metal sulfide standards. Despite the inherent inaccuracies of XPS quantitation, the XPS results help to correct for surface deviations from bulk stoichiometry owing to surface contamination, facile S surface oxidation, and preferential S loss usually observed during Ar+ sputter cleaning. The integral area Auger measurement techniques are particularly promising for electron‐beam sensitive materials which often cannot be characterized using high primary electron doses and conventional energy‐analyzer potential modulation differentiation.
An experimental and theoretical study of the transmission function of a commercial hemispherical electron energy analyser
Authors: Hughes A. E. , Phillips C. C.
Published: December 2004

The electron energy analyser transmission (peak area/incident current) of a VG Scientific ESCALAB has been measured as a function of kinetic energy, analyser energy and source position for a point source of electrons in the sample plane (produced using a specially designed mini electron gun). Results have been obtained in both CAE (constant analyser energy) and CRR (constant retard ratio) modes. The results are extrapolated to give the energy dependence of the analyser transmission for an extended current source, such as encountered in routine XPS analysis applications. A detailed theoretical study explains the rationale behind this data extrapolation and predicts an analyser transmission in fair agreement with experimental results, possible causes for the discrepancies between theory and experiment are discussed.
Interfacing AEI/Kratos electron spectrometers to a microcomputer for data acquisition and processing
Authors: Evans Stephen , Elliott David A.
Published: December 2004

Interfacing of a Research Machines Ltd. 380Z microcomputer to an AEI/Kratos ES200 electron spectrometer and Inotech multichannel analyser (MCA) is described. Comprehensive data acquisition and processing facilities are thereby provided. The microcomputer controls the MCA, the ES200 sweep ramp and the ES200 analyser kinetic energy (KE) above which the sweep is applied. The operating and processing program has been developed predominantly in BASIC, permitting the retention of more flexibility than is usual with ‘packaged’ computer systems. Facilities are provided for rapid quantitative elemental analysis by XPS following the automatic execution of repetitive sweeps over a sequence of up to 10 KE regions. Peak maximum KEs and widths are also computed, and X‐ray satellite contributions can be subtracted from the spectra. In addition, integral spectra, 5–25 point smoothed spectra and their first and second derivatives can be generated.
On depth profiling an InGaAsP‐InP heterojunction
Authors: Landers R. , Prince F. C. , Sundaram V. S. , Patel N. B.
Published: December 2004

An In0.71Ga0.29As0.63P0.37/In0.97Ga 0.03 As0.10P0.90 liquid phase epitaxy (LPE) grown low lattice mismatch (δa/a ≤ 0.03%) interface has been profiled using 1 keV argon ions incident at 50° to sample surface normal in a commercial Varian Auger system. It was found that an interface width of 160 Å from P (120 eV) Auger peak intensities.
The depth dependence of the depth resolution in composition–depth profiling with Auger Electron Spectroscopy
Authors: Seah M. P. , Hunt C. P.
Published: December 2004

The depth dependence of the depth resolution in composition–depth profiles using Auger electron spectroscopy is briefly appraised to emphasize some of the different mechanisms operating for different classes of material and to show how the use of a characterized Ta2O5 on Ta reference material can help to optimize the depth resolution. In addition it is shown that, even for flat uniformly‐layered samples sputtered under ideal conditions where the ion beam crater is flat and impurities may be ignored, five factors still limit the depth resolution: information depth, statistical effects and cascade mixing, electron stimulated desorption and sample roughening. These may each be observed to dominate at the appropriate depth for amorphous materials but, for evaporated polycrystalline metal films, the last term dominates for depths greater than 10 nm.
Ion beam induced composition changes during auger sputter profiling of thin Al films on InP
Authors: Skinner D. K. , Swanson J. G. , Haynes C. V.
Published: December 2004

Auger sputter profiles of thin AI films on InP are presented and shown to be susceptible to an unusual type of ion beam induced interfacial distortion. It is found that recoil implantation and atomic mixing produce a differential broadening of the In and P at the interface which can seriously affect the integrity of the Auger profile. Energy shifts in the AI Auger peak indicate that this distortion is associated with AIP formation to a depth dictated by the ion beam energy and species. Experimental requirements for the reduction of interfacial distortion are discussed. We also consider the influence of the ion beam on the topography and morphology of the InP surface in relation to interfacial distortion.
Bonding of adhesive primers to aluminium substrates
Authors: Yaniv A. E. , Klein I. E. , Sharon J. , Dodiuk H.
Published: December 2004

A study was made on the influence of sulphuric and chromic acid anodizing on the polymerization behavior of four primers (three based on epoxy resins and one on polyurethane) using IR and AES spectroscopy. AES spectroscopy has revealed that sulphur anions were incorporated in the anodic film, but no chromium anions could be detected. IR spectra for the primers on chromic acid anodic films are similar to those obtained on untreated aluminium, but a change of absorption peaks was observed for sulphuric acid anodic film substrate. Sulphuric acid anodizing has an adverse effect on the polymerization of the primers studied in this work.
Molecular orientation and structure of copper–benzimidazole films
Authors: Tompkins H. G. , Allara D. L. , Pasteur G. A.
Published: December 2004

Infrared spectra of benzimidazole, a copper–benzimidazole complex in powder form, and a copper–benzimidazole complex which forms as a film on metallic copper are presented. The spectrum of the film on the metal exhibits peak absorbances similar to those of the copper–benzimidazole powder spectrum. It appears from relative peak heights that, in the film, the complex is preferentially oriented with the plane of the benzimidazole ring parallel to the metal surface.
Suppression of molecular ions in the secondary ion mass spectra of minerals
Authors: Metson J. B. , Bancroft G. M. , McIntyre N. S. , Chauvin W. J.
Published: December 2004

A new approach to the suppression of molecular ions in secondary ion mass spectra of insulating specimens is reported. Using a Cameca IMS 3f instrument, with unconventional primary beam conditions and uncoated samples, it has been possible to almost eliminate the contribution of molecular ions to the mass spectrum. This has resulted in excellent discrimination for major and trace element detection in these materials, including complete resolution of the rare earth elements in a number of minerals.
Secondary ion emission of metal oxide species and their dependence on the fragment valence
Authors: Van Craen Marc J. , Adams Fred C.
Published: December 2004

Secondary ion yields for dynamic SIMS analysis of oxidized metal and metal oxide surfaces were determined. The dependence of the ion yield with the fragment valence for molecular secondary ion species of the MxOy± type can be described by a Gaussian, whose width and maximum decreases with the number of metal atoms in the cluster. The systematics of parameters, such as the variance of the Gaussian, the total ion yield, the lattice valence and its shift with the oxidation state of the metal in the solid, were investigated. The practical use of the derived relationships is demonstrated.
Surface characterization of chemically modified (trimethylsily) silicas by 29Si solid state NMR, XPS, and IR photoacoustic spectroscopy
Authors: Linton R. W. , Miller M. L. , Maciel G. E. , Hawkins B. L.
Published: December 2004

The surface reactivity of hydroxyl groups on silica with trimethylchlorosilane (TMCS) is examined using XPS, FTIR‐PAS, and solid state NMR. All techniques give responses give responses which can be correlated with increasing TMS surface coverages on Lichrosorb Si 60 silica and provide detection limits of ⩽10% of a TMS monolayer. Solid state NMR is particularly suited to examining reactivity differences between geminal and single silanols. Geminal hydroxyl groups are found to be much more reactive. At higher TMS coverages approaching steric limitations (0.5 TMS monolayer), nearly 100% of the geminal sites are reacted as opposed to only 20% of the single sites. The reactive subset of single silanols appears to include hydrogen‐bonded (vicinal) groups. A mechanism is postulated to explain the apparent enhanced reactivity of geminal and vicinal silanols.
The role of surfaces and interfaces in wear, adhesion and breakdown phenomena
Authors: Le Gressus C. , Maire Ph.
Published: December 2004

Phenomena of wear, adhesion, dielectric breakdown, etc. are dealt with by specialists in different fields (solid state physics, thermodynamics, mechanics) and it is hard to establish links between the various approaches. We have tried to achieve this by the use of surface methods, taking as the basis the insulating nature of technological surfaces and attempting to relate their technical properties (wear, adhesion, wetting, etc) to their specific physical properties (surface tension, defects, conductivity). Although in principle the physical properties investigated are accessible through chemical analysis, an explanation for the phenomena observed in practice was obtained by study of the elementary phenomena occurring on model surfaces (adsorption, segregation, charges, etc.). The points of interest were the origin of the coupling which exists between surfaces properties and volume properties, that of fracto‐emission phenomena and that of electrostatic phenomena observed during wear, adhesive stripping, etc. It is important to clarify these points, on which various theories of adherence and wear are based. Their explanation will be shown to lie in the electronic and vibrational structures of imperfect insulators and the polarization of insulators subjected to mechanical, thermal and electrical stresses. They give information about the different modes of energy dissipation in the solid and the influence of defects on the cohesion energy. The study of these different factors thus links up directly with the thermodynamic and chemical approach to the properties of insulators, which only adds to the importance of the current fall‐out from surface sciences.
Application of a crystal spectrometer to particle induced X‐ray emission analyses of GaAs crystals
Authors: Narusawa Tadashi , Ohyama Hideaki , Nakashima Hisao , Hayashi Shigeki , Koyanagi Kazuo , Kumashiro Sumio , Soejima Hiroyoshi
Published: December 2004

The application of a wavelength dispersive x‐ray spectrometer, instead of the conventional energy dispersive spectrometer, to particle induced x‐ray emission analyses of GaAs is reported in this paper. The apparatus and its feasibility are described in detail through measurements of standard samples, Si, Mg, and B in GaAs. The conclusion is that the technique is a good tool for light elements analysis in heavy materials such as GaAs, but proper application of the technique necessitates carefully chosen samples.