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By Ibrahim Yusufoglu, Cem Kahruman, Mert Zoraga

In this study, a strontium sulfate mineral (celestite) was converted to strontium oxalate in solutions containing ammonium oxalate as a reactant. The experiments were carried out under isothermal conditions. The effects of stirring speed, ammonium oxalate concentration, particle size and temperature on the conversion rate were investigated. During the conversion process, definite volumes of solutions were taken from the reactor after different reaction times for the determination of sulfate ions using ICPOES. Fractional conversions of strontium sulfate were determined at different times and fractional conversion vs time diagrams were generated. It was found that the conversion of strontium sulfate was increased by increasing the ammonium oxalate concentration and temperature in addition to decreasing the particle size. The effect of stirring speed was negligible on the reaction rate. It was observed that above 328 K, a protective layer of strontium oxalate was formed on the strontium sulfate particles. X-ray Powder Diffraction technique was used for characterization of solid substances.

Jan 1, 2014

By Reinhard F. Dobner

After a short introduction about the HK's secondary smelter process and explanations concerning the anodes produced the regulation and buffering of bleed will be described and the principles of technology for processing of bleed will be presented. Modernization aspects, especially installation equipment, and the different types of evaporators used will be described in detail. Besides, experience made with acid-resistant materials - stainless steel, enamel, plastics - will be reported. Environmental aspects such as water and air pollution will be outlined briefly and in conclusion the quality of products obtained as well as quality control will be presented.

Jan 1, 1997

By R. Ratnagiri, B. Minaie

"In order to expeditiously produce defect-free metallic components in materials processing applications, the relationship between the process parameters and the product properties needs to be well understood while minimizing the production engineering iterations. To achieve this goal, a realistic mathematical formulation of the process should be carried out and an appropriate numerical modeling of various phenomena occurring in such process should be implemented. The materials processing of transforming the molten material into a finished metallic component involves fluid flow and solidification/melting. In the present paper, a finite element based analysis of the fluid flow ·and solidification/melting phenomena in cavities is presented and the various issues in modeling these phenomena are discussed. These transport phenomena play an important role in determining the final characteristics and material properties of the part by affecting the formation of defects and microstructure. A realistic numerical modeling of these phenomena can significantly reduce the rejection rates during the process and can increase the quality of the final product.IntroductionDuring the intelligent materials processing of various metallic components, it is often required to have a thorough knowledge of the behavior of the transport phenomena involved in this process. This is due in large to the coupling that exists between the transport phenomena and the final material properties of the components produced during materials processing. This interrelationship demands that the pertinent transport phenomena in the form of fluid flow and solidification/melting be studied and predicted accurately. In many materials processing applications, the fluid flow is in the form of either a forced convection free surface flow intended to fill a cavity or a natural convection flow resulting from the gravity when the cavity is filled. In either case, the phase change in the form of solidification/melting is also involved in order to complete the process. However, the thermal history during this phase change has a direct impact on the material properties of the final part and the possible defect formation that may be involved. This thermal history itself is dependent on the nature of the fluid flow during the earlier stages of the process. As such, there is a coupling between the fluid flow, phase change, microstructure, and defect formation in the resulting component. It is therefore necessary to analyze these phenomena in order to find optimum methods to produce good quality parts by minimizing the defects that may be generated. Such an analysis can result in the development of appropriate numerical models for the process that can facilitate the economical and timely manufacturing of various components with high consistency. The present paper discusses the issues related to the transport phenomena encountered during materials processing of components engineered largely by using various combination of convective fluid flow and solidification/melting in cavities."

Jan 1, 1994

By Peter K. Liaw, Charlie R. Brooks, David C. Joy, Wei Zhao

In this paper, effects of oxidation, porosity and fiber-fabric stacking sequence on flexural strength of a continuous silicon carbide fiber (SiCr) fabric-reinforced SiC ceramic-matrix composite (CFCC) were studied. The failure mechanisms were correlated with flexural strengths of CFCC samples, both before and after oxidation. Microstructures and fractography were investigated using scanning electron microscopy (SEM). The chemical change after oxidation, such as Si, C, and 0, and their distributions, were detected by the SEM energy-dispersive X-ray spectroscopy (EDXS) line-scan chemical analysis technique. These effects on the strength of the CFCC can be attributed to following reasons: (i) The decrease in the flexural strength after oxidation is mainly due to degradation of the strength of Nicalon fibers and the damage of fiber/matrix interface both caused by high-temperature chemical reactions, (ii) Porosity is not too important in affecting the strength of the CFCC, when the bonding of the forced flow chemical vapor infiltration (FCVI)-SiC matrix is stronger than that of the fiber/matrix interface. However, a higher porosity content will be harmful, because higher porosity will both decrease the effective elastic modulus of the FCVI-SiC and make pore-linkage easier to occur, which is more likely to cause premature failure, (iii) The variation in the lamina stacking sequence of the CFCC changes the elastic stress distributions along the thickness direction of specimens, the magnitude of ceramic matrix-cracking stress, the effective elastic moduli of the laminate, and different crack initiation sites as well as different failure modes, and thus, leading to the scatter in the flexural strength of the CFCC.

Jan 1, 1998

By R. Moreau, V. Uspenski, K. Messadek, Y. Delannoy

Experiments and numerical simulations have been carried out to investigate the properties of quasi-2D turbulence. A new mercury model experiment has been built and tested in a uniform magnetic field up to 6T, (Ha~ 1000), ensuring a better two-dimensional behaviour than earlier versions (Alboussiere et al., 1997), limited to 0.2T. The quality of the experimental results has been improved in order to get wave number spectra (instead of frequency spectra) and higher signal over noise ratio (due to the higher magnetic fields). In parallel, some two-dimensional "direct" numerical simulations were performed using a commercially available code to solve a 2-D motion equation involving a source term to model the Hartmann layer. This term is derived from the condition of closure of the electric current, which allows to transfer the Hartmann effect into the 2D-core flow without simulating the layer itself (Sommeria & Moreau, 1982). No subgrid scale modelling is needed in such a two-dimensional situation where most of the energy is carried by the large scales.

Jan 1, 1999

By Yurniko Nakamura

Hydriding properties and crystal structure of a Ti-V- Mn solid solution alloy have been studied by P-C isotherm measurements and neutron and X-ray powder diffraction. The absorption P-C isotherm at 298K shows two plateau regions at 0.01MPa and 1MPa. The X-ray diffraction data have demonstrated that three phases with a BCC, a pseudo-cubic FCC and an FCC structure form subsequently with increase of the hydrogen content. Crystal structure of the latter two phases has been determined by Rietveld refinement of the neutron diffraction data. The FCC phase is the di-hydride of CaF2 type with hydrogen occupation in the T sites. The pseudo-cubic FCC phase is the mono-hydride of NaCl-type with hydrogen occupation in the 0 sites, which has not been reported so far. The lattice constants of the mono-hydride (Ti1.0V1.1Mn0.9)H_2.7 are a'=0.407 nm for two axes and c'=0.390 nm for the third axis. The a'axis is shorter by 4% than the c'axis. This pseudo-cubic FCC lattice is formed by contraction of 5% of the a axis and expansion of about 30% of the c axis from the original BCC lattice.

Jan 1, 2002

By Samson Adeosun, Sanmbo Balogun, David Esezobor

"Iron and steel making processes give rise to large amounts of usable and unusable materials, the latter generally being termed wastes. It is sometimes difficult to distinguish between re-usable by-products and wastes which cannot be sold or land-filled. Much depends on circumstances such as the local market for the material. This can itself vary from time to time with by-products which cannot be used or sold becoming wastes and vice versa. This paper defines the concept of “waste-free technology”, discusses its development in the steel industry and highlights the benefits of the technology to the manufacturing sector and the environment. The paper also articulates how the “waste-free” technology could be applied in the proposed Ajaokuta integrated steel plant in Nigeria.IntroductionIn the past, nature was considered an inexhaustible store. Its resources were consequently exploited and waste products therefrom were discarded. Today, attitudes have not changed appreciably even as raw materials cost rise by the year to pose a series of socio-economic problems, which, among others, may include the rational and optimum utilization of resources, environmental protection and reduction of waste formation. Consequently, industrialists now face unexpected regulatory pressure in areas of pollution prevention, waste minimization and hazardous waste disposal.Iron and steel making processes give rise to significant amounts of usable and un-usable materials, the latter generally being termed waste. It is sometimes difficult to distinguish between re-usable by-products and wastes which cannot be sold or land-filled. Much depends on circumstances such as the local market for the material. This can itself vary from time to time with by-products which cannot be used or sold becoming wastes and vice versa. In this paper, the term waste refers to those materials that are either irrationally utilized or, land-filled and part of the byproducts that are not utilized. It includes that part of used materials which is not incorporated into the products manufactured during a process stage and which in contrast to reuseable materials, is considered not suitable for any further use, owing to technical or economic factors. In general, these materials are inorganic and parts of them are either utilized or passed to the other processes; the other part should be disposed of using well-established waste disposal practices to avoid any environmental threat.Thus, creative methods must be developed to modify the manufacturing processes to reduce emissions and process wastes by fully utilizing all resources. One method of eliminating the negative effect of waste formation is the use of purification and cleaning structures (pollution control system, PCS). These are, however, quite expensive."

Jan 1, 2008

By Rodney T. Jones

DC arc furnaces were first used industrially for the reductive smelting of chromite fines to produce ferrochromium thirty years ago. Since then, they have been used for a variety of applications, including the smelting of ilmenite to produce titania slag and pig iron, the recovery of cobalt from non-ferrous smelter slags, and the smelting of nickel laterite ores to produce ferronickel. The power of these furnaces has increased from 12 MW to 72 MW for ferrochromium, and to 80 MW for ferronickel. The largest of these furnaces requires two electrodes to carry sufficient current to generate this much power. A review is presented of various DC arc furnaces in use, along with a discussion of the likely ways in which furnace power might be increased further in the future.

Jan 1, 2014

By Batric Pesic

Silver dissolution with thiourea was studied by using the rotating disk technique. The major parameters studied were: thiourea concentration (0-0.5M), ferric sulfate concentration (0-0.5M), sulfuric acid concentration (0-0.5M), and the effect of many foreign ions (Mn, o.i, Co, Ca, Na, etc.). Temperature effect was studied in the range 5-35 .C. The activation energy was 5.4 Kcal/mole. The dissolution of silver was first order with respect to ferric sulfate, and the secord order with respect to thiourea. Among the additives, copper had a dramatically negative effect. The strong oxidants such as hydrogen peroxide and manganese dioxide were also detrimental for silver dissolution. Silver does not dissolve with thiourea in the absence of ferric ions. Sulfuric acid does not participate in the dissolution reaction either. Chemically, the most important parameter for silver dissolution is the ferric sulfate/thiourea ratio. Thus, in the solutions with excess of ferric sulfate, a solid silver-thiourea complex is formed, which precludes transfer of silver into solution. In the solutions with the excess of thiourea, the free thiourea reacts with formed solid silver-thiourea complex and silver goes into the solution. The solid silver-thiourea complex was characterized according to its chemical composition. The complex contains 6.54%C, 2.49\H, 14.77%N, 16.09%0, 21.62%8, and 37.13% Ag. This composition corresponds to a Ag2so4.3'1U.2ff:i0 compound The soluble silver species are present in the solution as the dimers of AgTU+3 complexes.

Jan 1, 1989

By Courtney Young, Jerome Downey

"The various technologies developed for treating spent potlining (SPL) from primary aluminum smelters have been reviewed on several occasions. The technologies generally involve physical, chemical, and thermal processes, either individually or in combination, with the primary objective of total recycle, waste minimization, or complete disposal. In general, those technologies geared for recycling involve separations and are therefore subject to recovery inefficiencies that are attributed to several factors. However, the inefficiencies could be reduced or possibly eliminated if the pots were designed for recyclability. This concept is applied to SPLASH, a recently developed SPL management technology.IntroductionAluminum is produced by molten salt electrolysis via the Hall-Héroult process. The process is conducted in an electrolytic “pot,” which is comprised of a steel frame first lined with insulating refractory brick, and then conductive graphite blocks, which serves as the carbon cathode [1, 2]. These materials are collectively referred to as “potlining.” Anodes comprised of petroleum coke/pitch are suspended above the pot and extend down into the molten cryolite (Na3AlF6) electrolyte. The electrolyte temperature is maintained at approximately 980 °C by resistance heating as low voltage (4-5 volts) and high current (50,000-300,000 amps) are applied across the two electrodes.High purity alumina is added to the cryolite bath, where it dissolves and becomes amenable to aluminum reduction at the cathode:"

Jan 1, 2008

By Jiling Wang, Xuefeng Liu, Haojian Duan, Lifeng Zhang, Ying Ren, Wen Yang

"In order to study the influence of MgO-C refractory on steel cleanliness and inclusions during steelmaking process, and to understand the reaction mechanism deeply, laboratory deoxidation and equilibrium experiments were respectively performed in MgO crucibles at 1873K. In the former experiment, after Al addition, steel samples were taken at different holding time. In the latter experiment, different slag components and different contents of carbon and aluminum in steel were considered respectively. The inclusion characteristics of each experiment were analyzed. The results showed that with the increasing of holding time after deoxidation by Al, MgO existed in the small inclusions firstly, and then in the large ones such as the clusters. The MgO content in the inclusions increased with the increasing of holding time, indicating that the MgO in crucible could be individually reduced by the aluminum in the molten steel. The reaction could occur within nine minutes.IntroductionNon-metallic inclusions would have positive or negative effect on steel quality depend on the quantity, size and composition of inclusions. Large inclusions are always detrimental. From the point of view of inclusion property, plastic inclusions are required by steel cord, while hard inclusions are preferred by pipeline steel. One of the most important ways to increase the steel quality is reducing the inclusion size and controlling the inclusion composition in steel. Nowadays, MgO based refractory is used as ladle glaze material with more and more frequency, which results in different inclusion characteristics in molten steel, for example, the inevitable generation of MgO contained inclusions during ladle treatment of steel. In other words, the inclusions in this type ladle will influence on the steel cleanliness and the product property. Thus, keeping an eye on the inclusion formation behavior in the steel with MgO-C ladle glaze is important for the steel industry. There have been a few studies in this regard. Li et al[l] studied the reactions between MgO-C refractory, molten slag and metal using a high temperature X-ray radiographic apparatus. They found that the local corrosion was regarded as due to the cyclic dissolution of MgO and graphite in the refractory into slag and metal phase. The gas bubbles formed according to the reaction of (FeO)+C(s)=Fe(l)+CO(g) greatly influenced the corrosion. On an industrial scale, Du[2] found that ladle glaze is a major source of inclusions in the ladle. An experimental study has been performed by Lehmann in order to estimate the importance of the reaction between a MgO-based tundish refractory and an Al-killed steel[3]."

Jan 1, 2014

By Damien Wagner

To reduce the emission of greenhouse gases by the steel industry, particularly for ironmaking, the production of DRI (Direct Reduced Iron) using hydrogen as the reducing gas instead of carbon monoxide is being considered. In this context, the reduction of pure hematite by hydrogen was studied at the laboratory scale, varying the experimental conditions and observing the rate and the course of the reaction. All the reduction experiments were performed in a thermobalance and supplementary characterization methods were used like scanning and transmission electron microscopy, X-ray diffraction, and Mössbauer spectrometry. The influence of rising temperature in the range 550-900°C is to accelerate the reaction; no slowing down was observed, contrary to some literature conclusions. A series of experiments consisted in interrupting the runs before complete conversion, thus enabling the characterization of partially reduced samples. Interpretation confirms the occurrence of three successive and rather separate reduction steps, through magnetite and wustite to iron, and illustrates a clear structural evolution of the samples. Finally, the influence of the sample type was revealed comparing a regular powder, a nanopowder and a sintered sample. The regular powder proved to be the most reactive despite its larger grain size, due to a more porous final structure.

Jan 1, 2006

By Demaerel. J. P.

Arsenic plays a major role during electroreflning of copper. Both the arsenic content in the anode and the arsenic concentration of the electrolyte have, in conjunction with other impurities such as lead, antimony, bismuth and oxygen, a direct influence on the quality of the cathode. The mechanisms are currently slime. inclusion and precipitation of insoluble compounds in the bulk of the electrolyte. Arsenic has also been reported to have a depassivating effect on the anode. An influence on the anode slime adhesion has also been found. A literature survey is given and these data are compared with and completed by our own results based on lab and pilot scale experiments as well as on Olen tank.house practice.

Jan 1, 1987

By Howard K. Worner

"In a rewarding career spanning nearly two thirds of a century, the author has worked at the frontier of such diverse fields as the creep of metals, structure properties and production of novel dental and surgical materials, molten salt electrolysis for titanium production, greatly improving the productivity of large iron blast furnaces and of oxygen steelmaking. While each of these has given great satisfaction, special thrills have derived from the development of new methods for the continuous production or refining of both ferrous and non ferrous metals. A rewarding segment was the evolution of various aspects of WORCRA technology. Unfortunately, several of these inventions have been ""ahead of their time"". Introduction""I am greatly honoured by the convening of this meeting to recognise my contributions to pyrometallurgy. My appreciation is the greater because this is the third Howard Worner Symposium; the first took place in the University of Newcastle in 1988, close to my 75th birthday. It was arranged by the local branch of The Australasian Institute of Mining and Metallurgy with the theme, ""Frontiers in Pyrometallurgy"". The second was organised by the University of Wollongong in conjunction with the Australian Academy of Science and the Australian Academy of Technological Sciences and Engineering; it celebrated my 80th birthday and, at my request, covered a broad range of topics under the heading of ""Recent Advances in Science and Technology"". Now, this very international meeting on ""Injection in Pyrometallurgy"" has been convened by the G K Williams Co-operative Research Centre for Extractive Metallurgy in my alma mater. I am both delighted and honoured that the cosponsors are the TMS (USA) and ISIJ (Japan).Dr Madhu Nilmani consulted me about the field to be covered and I readily concurred because ""injection"" has been of keen interest to me since the beginning of the 1960s when I began my pioneering work on sequential oxygen (or air) injection into flowing streams for both refining of blast furnace hot metal to steel and for the continuous smelting-converting of copper and nickel."

Jan 1, 1996

By C. D. Adams, R. T. Tuenge, C. N. King, J. A. Samuels, B. F. Espinoza, R. C. Dye, C. F. Schaus, D. C. Smith, N. M. Peachey

"Recently, doped calcium thiogallate (CaGa2S4) phosphors have been investigated for use in electroluminescent flat panel displays. The current technique used for the deposition of thin film calcium thiogallate is sputtering. Unfortunately, this requires a high temperature annealing process to provide the desired crystallinity of the phosphor. Recent efforts have focused on the possible use of metal-organic chemical vapor deposition (MOCVD) to produce the CaGa2S4 layer. The use of MOCVD provides an attractive alternative to sputtering since it does not require heating above the strain point temperatures of the glass substrates used for the display panels. To accomplish this, the deposition of both Ga2S3 and CaS is investigated as these compounds are intermediate steps in the development of the phosphor deposition. Uniform, crystalline films of both Ga2S3 and CaS were deposited and the process shows promise for successful deposition of the CaGa2S4 phosphor.IntroductionThe lack of a satisfactory blue phosphor having sufficiently high luminances at low power has hampered the development of high resolution flat panel displays. Recently, a new series of blue emitting materials have been investigated for use in thin film electroluminescent (TFEL) devices. l ,2,3 These phosphors are based on a series of alkaline earth thiogallate host materials of the form MGa2S4:RE where M can be either calcium, strontium, zinc, or barium and RE is a rare earth ion. A full-color VGA TFEL panel using CaGa2S4:Ce as the blue phosphor has recently been fabricated and tested. l This FPD provided a luminance of 10 cdlm2 at 60 Hz. The enhanced blue in this display allowed its color capabilities to approach those of the conventional CRT.The method of depositing the phosphor onto the display panels in these test devices has been sputtering. Unfortunately the phosphor as deposited does not possess the crystalline properties required for optimum luminance. The crystalline structure is achieved by subsequent annealing of the deposited material. Although this post deposition anneal provides the desired crystal structure, it occurs above the strain point temperature of ordinary glass. Consequently, the implementation of these phosphors requires the use of glasses capable of withstanding high temperatures, adding to the cost of the final display unit."

Jan 1, 1994

By Rajesh S. Ransing

An intelligent tool has been developed to analyse the quality of diecast components. The influence of both design and process parameters has been studied in great detail. The tool, based on expert systems related technologies, can identify the causes for the defective castings manufactured. Design related causes such as gate position; gate area, runner design etc. as well as process related causes such as cycle time, cavity filling time and melt temperature are suggested by analysing the data on defective castings for a manufacturing campaign. This intelligent analysis is useful for both design as well as production engineers in the decision making process. All the causes for the occurrence of defects are classified into two categories. The firs category is the 'rootcauses' i.e. the causes which are related to the actual process, material and design parameters and which can be directly monitored. The second category is more abstract in nature and is classified as `metacauses'. These capture the scientific rationale implicit in the cause and defect relationships. This knowledge on causes and defects is represented in the form of a structured graph rather than by a set of rules, which, coupled with forward reasoning and heuristic search techniques results in an elegant and efficient approach. Uncertainties and the degree of relationship among causes and defects are represented by a fuzzy probabilistic model.

Jan 1, 1994

By Oszkar Bíró, Peter Mittag, Bernhard Aigner, Stefan Pirkeri, Philipp Glttleri

"This paper considers CFD modeling of processing and melting of small metallic particles by means of electrical heating. The particles fall continuously onto a liquid metal bath which is heated by an electric arc. After melting of the particles liquid metal is tapped.The charging behavior of the particles in the supply unit as well as in the reactor freeboard is studied by means of Euler-Euler granular simulations. The flow situation in the metal bath due to gas injection and magnetic fields is calculated by combining Navier-Stokes and Maxwell solvers. The macroscopic melting process occurring during the continuous charging of the particles is studied by kinetic laws for melting reactions. The temperature field is evaluated by balancing heat sources due to Joule's heating and heat losses due to latent heat of melting as well as convection and radiation.As a result of these simulations the fully three-dimensional flow fields of particles and gas in the atmosphere is obtained. Furthermore the flow field as well as the magnetic field in the metal bath can be studied. As a main result the three-dimensional concentration field of the still unsolved particles in the liquid metal can be evaluated.IntroductionIn this paper a metallurgical process for melting small iron particles is investigated by means of CFD-simulations. In a first process step the preheated and already mostly reduced iron particles fall continuously into the reactor through a vertical tube mounted at the lid of the furnace. In a second step the particles are melted in the liquid metal bath. Meanwhile the melt is heated by electric arcs to provide the heat needed for melting the incoming particles.In Figure I a sketch of the geometry setup considered in this paper is provided. The particles fall from a height of approximately 12 meters onto the bath surface in the center of the furnace. The melt is heated by electric arcs that are placed symmetrically around the center axis."

Jan 1, 2001

By William A. Apel

Several different strains of bacteria have been shown capable of reducing hexavalent chromium, Cr(VI), to Cr(III), a less toxic, .. more readily recoverable form of Cr. This paper examined the Cr(VI) reduction efficacies of 3 different Cr(VI) reducing bacteria: Pseudomonas f1uorescens LB300., Pseudomonas aeruginosa PAOI, and Pseudomonas aeruginosa PAOI (pCROI) It was demonstrated that all three bacterial stratns reduced Cr(VI) primarily during their exponential growth phases while using glucose as their carbon and energy source. Significant differences in the three organisms' Cr(Vl) reduction capabilities depending on initial Cr(VI) concentrations were also demonstrated. P. aeruginosa PAOI showed superior Cr(VI) reducing capabilities over the. entire range of Cr(VI) concentrations tested while the Cr(VI) reduction capabilities of the other two strains were increasingly inhibited as Cr(VI) concentrations increased.

Jan 1, 1991

By Mark Jolly

"Over the last ten years or so many man hours have been dedicated to developing methods for simulating shape casting processes. The majority of the methods developed have been devised by a combination of computer, mathematics and materials specialists often with limited knowledge of foundries and foundrymen. As a result of this it would appear that although there are many software packages for the foundryman to use there still exist fundamental misunderstandings as to their usefulness and suitability within the foundry.The paper aims to identify how well current software packages perform. The relationships between physical phenomena, practical defects and software capabilities are presented. Some discussion of the use of criteria functions is also presented. Finally issues arising from the postprocessing of results are discussed as the presentation of the results to the lay-person in simulation techniques is possibly one of the most important aspects in influencing the adoption of this type of software in the foundry community."

Jan 1, 1999

By H. L. Ludtke

Microlaminate composites were fabricated by electron-beam physical vapor deposition. The microlaminates consisted of five layers, each 2 to 4 pm thick, and were composed of either pure metal layers (Cu-Ag), or alternated between metal and intermetallic layers (Nb(Al)- Nb3Al). The microlaminates were heat treated in an Ar atmosphere for 2 to 12 hours, at temperatures of 600°C for the Cu-Ag and 1000°C to 1200°C for the Nb(Al)-NbsAl. Microlaminates were examined after deposition and after heat treatment by scanning electron microscopy and energy dispersive x-ray spectrometry. The effects of heat treatment on the morphological stability of these composites will be described.

Jan 1, 1999