Showing papers on "Microstructure published in 1988"

New Fe-based soft magnetic alloys composed of ultrafine grain structure

Abstract: The magnetic properties of Fe‐Si‐B‐M (M: additives) alloys prepared by annealing amorphous alloys made by the single roller method over their crystallization temperature have been investigated for development of new Fe‐based soft magnetic alloys. Excellent soft magnetic properties were obtained by adding the two elements Cu and Nb to Fe‐Si‐B alloys. It was found that these new alloys, called ‘‘FINEMET,’’ have an ultrafine grain structure composed of bcc Fe solid solution. They are suitable for many kinds of magnetic components such as saturable reactors, choke coils, and transformers, because they have superior soft magnetic properties and a high saturation flux density, and because different types of B‐H hysteresis loops are obtained by magnetic field annealing.

High critical currents in Y‐Ba‐Cu‐O superconductors

Abstract: Melt‐textured growth of polycrystalline YBa2Cu3O7−δ superconductor using directional solidification created an essentially 100% dense structure consisting of long, needle‐ or plate‐shaped crystals preferentially aligned parallel to the a‐b conduction plane. The new microstructure, which completely replaces the previous granular and random structure in the sintered precursor, exhibits dramatically improved transport Jc values at 77 K of ∼17 000 A/cm2 in zero field and ∼4000 A/cm2 at H=1 T (as compared to ∼500 and ∼1 A/cm2, respectively, for the as‐sintered structure), with the severe field dependence of Jc (‘‘weak‐link’’ problem) no longer evident in the new melt‐textured material. The improvement in Jc is attributed to the combined effects of densification, alignment of crystals, and formation of cleaner grain boundaries. Microstructure and distribution of various phases present in the melt‐textured material are discussed in relation to the superconducting properties.

Granular and superconducting-glass properties of the high-temperature superconductors

Abstract: The microstructure of bulk samples of the copper-oxide high-temperature superconductors commonly is describable in terms of anisotropic grains of stoichiometric material separated by layers of nonstoichiometric interface material. The granularity strongly influences the electromagnetic properties, especially the transport critical-current density and the magnetization. In this paper, a simple theoretical model for the granularity is introduced and then used to discuss a number of electrodynamic properties (hysteretic magnetization versus magnetic field, zero-field-cooled and field-cooled magnetization versus temperature, ac susceptibility, and flux creep with logarithmic time dependence). Special attention is drawn to the importance of distinguishing between intragranular and intergranular effects.

New Amorphous Mg-Ce-Ni Alloys with High Strength and Good Ductility

Abstract: New Mg-based amorphous alloys with high strength and good ductility were produced in the Mg-Ce-Ni system by melt spinning. The tensile fracture strength ( σf) and Vickers hardness reach 750 MPa and 199 DPN for Mg80Ce10Ni10. The specific strength defined by the ratio of σf to density is as high as 27, being considerably higher than the highest value (20) for conventional Al-based alloys. The high-strength Mg-base amorphous alloys are expected to attract much attention as a new type of high-strength material with low density.

Synthesis, characterization, and properties of nanophase TiO 2

Abstract: Ultrafine-grained, nanophase samples of TiO2 (rutile) were synthesized by the gas-condensation method and subsequent in situ compaction. The samples were studied by a number of techniques, including transmission electron microscopy, Vickers microharness measurements, and positron annihilation spectroscopy, as a function of sintering temperature. The nanophase compacts with average initial grain sizes of 12 nm were found to densify rapidly above 500 °C, with only a small increase in grain size. The hardness values obtained by this method are comparable to or greater than those for coarser-grained compacts, but are achieved at temperatures 400 to 600 °C lower than conventional sintering temperatures and without the need for sintering aids.

Effects of oxygen and heat treatment on the mechanical properties of alpha and beta titanium alloys

Abstract: Two alloys, Ti-6Al-2V and Ti-2Al-16V, simulating the alpha and beta phases of Ti-6A1-4V, respectively, were prepared with oxygen concentrations from 0.07 to 0.65 wt pct (0.20 to 1.83 at. pct). Their microstructure, deformation behavior, and strength were investigated with X-ray diffraction, microscopy, and mechanical tests to determine the effects of oxygen concentration and heat treatment. In both alloys the hardness increases in identical fashion with the square root of oxygen concentration. The alloys' strengths also depend on heat treatment, but in different ways. Whereas the alpha alloy is non-age-hardenable, the beta alloy's strength can be doubled by aging. The hardening effect of oxygen is generally unaffected by heat treatment, except for the alloys with the highest oxygen concentrations. During aging of the alpha a small amount of Ti3Al can form, and slight age-hardening occurs. The ductility of the alpha alloy is little affected by aging. On the other hand, oxygen causes a change from good ductility at low oxygen concentration (0.07 wt pct) to total brittleness at 0.65 wt pct oxygen, independent of heat treatment. In the beta alloy there are complex phase transformations depending on heat treatment. Its deformation behavior varies from very ductile in solutiontreated and quenched (STQ) condition to totally brittle in aged conditions. The aging embrittlement appears to be caused by alpha and some omega precipitation. Decoration of the beta grain boundaries with precipitates accounts for the intergranular brittle fracture. Oxygen, on the other hand, is not an embrittler, although it reduces the ductility of the beta alloy.

Quantitative characterization of the transition zone in high strength concretes

Abstract: Synopsis The microstructure of the transition zone in high strength concretes, with and without silica fume, was characterized. Backscattered electron (bse) imaging combined with quantitative image...

Microstructure and the light‐induced metastability in hydrogenated amorphous silicon

Abstract: Using a parameter obtained from infrared measurements of the silicon‐hydrogen stretch mode, the amout of light‐induced degradation in hydrogenated amorphous silicon (a‐Si:H) has been explored as a function of the amount of microstructure present in our samples. We find that samples with more microstructure, and also more bonded hydrogen, show an increased light‐induced effect. At the same time, the volume density of states in the initial (annealed) state remains virtually unchanged. We discuss how the present results relate to existing models proposed to describe the light‐induced effect.

Effects of aging on the microstructure of 17-4 PH stainless steel

Abstract: Microstructures developed in commercial 17-4 PH precipitation-hardened stainless steel after different heat treatments have been studied. The martensite formed in this alloy has been found to be of a lath morphology having a dislocated substructure. Transmission electron microscopy studies have revealed the formation of a copper-rich phase in the samples aged at temperatures below 550°C. However, at higher temperatures, in addition to the formation of these precipitates, austenite phase reversion has been noticed, primarily at the lath boundaries. The reversion process has been found to be accompanied by a sharp decrease in the hardness of the alloy. The morphologies of the transformation products and the crystallography of the transformation have been discussed.

Electrical properties and microstructure in the system ceria-alkaline earth oxide

Abstract: The ionic conduction of oxygen in the ceria-alkaline earth oxide system was investigated as a function of temperature, partial pressure of oxygen and oxide composition, together with its crystal structure, density, and microstructure. Undoped ceria and its solid solution with alkaline earth oxides have a cubic fluorite structure. The ionic conductivity of ceria is greatly enhanced by additions of calcia and strontia, even when they are added in excess of the solubility limit. The conductivities of ceria-calcia and ceria-strontia were much higher than those of calcia-and yttria-stabilized zirconia. Up to the limit of calcia and strontia, the ionic transference number was nearly unity in the temperature range between 600 and 900°C. With an increase in calcia and strontia content, the ionic conductivity was little affected by the presence of a second phase of CaO and SrCeO3.

Ceramic Microstructures '86: Role of Interfaces

Abstract: Progress in the Understanding of Ceramic Microstructures and Interfaces since 1976.- Ceramic Microstructures: The Art of the Possible.- Designing Material Structures.- Purposive Design of Nanocomposites: Entire Class of New Materials.- Design of High Thermal Expansion Glass-Ceramics Through Micros truetura1 Control.- Microdesigning of Ceramic-Metal Composites.- Characterization of Microstructures.- Grain Boundaries and Interfaces: Some Applications of Electron Microscopy and Microanalysis.- Quantitative Characterization of Microstructural Geometry of Interfaces.- Gas Transport as a Tool for Structural Characterization of Inter facial Phases.- Unit Cell Distortion of Pb(Zr,Ti)O3 by Pb(Co,Nb)O3.- Electron Microscopy Studies of BaTiO3~NaNbO3 Ceramics.- Analytical Electron Microscopy of the Glassy Phase in Mullite/Zirconia Composites.- Microstructure Characterization of Basalt Glass-Ceramics.- Interfacial Reaction Between Bioactive Glass and Synthetic Physiological Solution.- Oxidation and Microstructure of Sintered Silicon Nitride.- Origin of Cracking Phenomena Observed in Decomposition Reactions.- Characterization of Interfaces.- Oxide Interfaces: Theory of Oxide-Oxide and Oxide-Metal Interfaces.- Green Function Method for Calculation of Atomistic Structure of Grain Boundary Interfaces in Ionic Crystals.- Comparison of the Energies of Symmetrical and Asymmetrical Grain Boundaries.- The Structure of a Natural Grain Boundary in a Magnetite Bicrystal Studied by XRD Technique.- Interface Morphology in Ceramics.- HREM Study of a Tetragonal ? Monoclinic Martensitic Interface in a Y2O3-Stabilized ZrO2 Alloy.- Control of the Tetragonal to Monoclinic Phase Transformation of Yttria-doped Tetragonal ZrO2 Polycrystals by Annealing in Water.- Grain Boundary Energy of Twisted MgO Bicrystals on (100).- T.E.M. Statistical Characterization of Grain Boundaries in Polycrystalline NiO Scales Obtained by High Temperature Oxidation of Nickel.- Structure of High-Angle Grain Boundaries in NiO.- High-Angle Grain Boundaries in Sheet Silicates (Biotite/Chlorite): A TEM Study.- HRTEM Analysis of Ordered Grain Boundaries in High Purity Alpha-SiC.- Atomic Structure of Interfaces in Sialon Ceramics.- Characterization of Impurity Segregations.- Atomistic Lattice Simulations of the Structure, Energetics and Impurity Segregation Behaviour of Ceramic Boundaries.- Distribution and Influence of Minor Constituents on Ceramic Formulations.- Characterization of Interphase Interfaces.- Diffusion Bonding of Metal/Ceramic Interfaces-A Model Study at the Nb/Al2O3Interfaces.- Ceramic-Metal Reactions and Their Effect on the Interface Microstructure.- The Influence of Surface Roughness on Interface Formation in Metal/Ceramic Diffusion Bonds.- A Reappraisal of Wetting in the System AI-AI2O3 from 750-1000 C.- Microstructural Characterization of Ni/Al203 Diffusion Bonds.- Bonding Ceramic-Metal Interfaces and Joints.- Copper-Glass-Ceramic Interfaces and Composites: Reactions, Microchemistry, and Electrical Properties.- The Study of Microstructures for Pt-Silicide Interfaces after Nd:YAG Laser Irradiation by XRD, SEM, XPS, and RBS.- High Resolution Electron Microscopy of Silicon Nitride-Metal Bonded Interfaces.- Interfacial Chemistry and Bonding in Fiber Reinforced Glass and Glass-Ceramic Matrix Composites.- Effects of Interfacial Diffusion Barriers on Thermal Stability of Ceramic Fibers.- Solid State Bonding of Alumina and Steel by HIPING.- Thermochemical Analyses of Interface Reactions in Carbon-Fiber Reinforced Glass Matrix Composites.- Interfaces in Heterogeneous Dissolution of Oxides in Molten Ca-Al-Silicates.- Microstructure Development.- Powders, Interfaces, and Processing: Alumina as a Case Study.- The Role of Powder Packing in Sintering.- Effect of Pores on Microstructure Development.- Microstructure Development of Hydrothermal Powders and Ceramics.- The Colloidal Chemistry of Growing Silica Spheres.- Effects of Vapor Transport on Microstructure Development.- Controlling Grain Growth.- The Effects of Grain Growth on the Intergranular Porosity Distributions in Hot-Pressed and Swelled UO2.- Effects of Solutes on the Grain Boundary Mobility of TiO2.- Microstructural Development in Hot Pressed CaO: Density Decrease and Pore Growth During Post Sintering.- Diffusion Induced Interface Migration in Ceramics.- Grain Boundary Diffusion Artefacts in Polycrystalline Nickel Oxide Grown by High Temperature Oxidation.- Variations in Grain Growth of Donor-Doped SrTiO3 with Cation Nonstoichiometry.- The Wetting and Dewetting of Grain Boundaries.- Anion Controlled Microstructures in the Al2O3-AIN System.- Sintering.- Sintering Theory for Crystalline Solids.- Selected Sintering Conditions for SiC and Si3N4 Ceramics.- Colloidal Consolidation and Sintering Behavior of CVD-Processed Mullite Powders.- Sintering of Acicular NiZn-Ferrite Powder.- Continuous SiC Fiber/Glass Composites.- Electrical Properties.- Electrical Conductivity in Ceramics: A Review.- The Crystallographical and Chemical Relationship between Intergranular and Bulk Resistivity in Semi-Conductor Oxides.- Interface Effects in Zinc Oxide Varistors.- The Role of Inter facial Microstructure in ZnO Varistor Materials.- Electrical Properties and Microstructure of ZnO-Nb2O5~MnO Ceramics Sintered in the Liquid Phase.- New Composite PTC Materials Based on PbTiO3-TiO2.- Effects of Microstructure Control on Ferroelectric Ceramics.- Effect of Deviations from Stoichiometry on Microstructure and Magnetic Properties of Ferrites.- Optical Effects of Grain Boundaries in PLZT Ceramics.- Microstructures of High Dielectric Constant Materials.- Interfaces Generated by Electronic Device Development in Beta SiC Thin Films.- Electrical Barriers at Grain Boundaries in Silicon Carbide Materials with BeO Addition.- Microstructural Analysis of Silicon Carbide Materials with BeO Addition.- Mechanical Properties and Behavior.- The New Generation of High Toughness Ceramics.- Influence of Microstructure on Creep Rupture.- Mechanisms of Dynamic Failure in Debased Alumina.- Some Interfacial Related Properties of Transformation Toughened Ceramics.- Precipitation in a (Mg) Partially Stabilized Zirconia during Aging at 1000 C.- High Temperature Mechanical Properties of ZrO2-Based Ceramics.- Microstructure and Mechanical Properties of a Al2TiO5-Mullite-ZrO2 Composite Obtained by Reaction Sintering.- Interfaces in Ceramic Fiber Composites.- Delamination Toughening from Interfacial Cracking in Ceramics and Ceramic Composites.- Development of Structure in Silicon Nitride Grain Boundaries.- The Impact of Compositional Variations and Processing Conditions on Secondary Phase Characteristics in Sintered Silicon Nitride Materials.- Structure and Chemistry of Interfaces in Silicon Carbide-Containing Materials.- Interfaces in Alumina-SiC Whisker Composites.- Creep Performance of Silicon Carbide Whisker-Reinforced Alumina.- Temperature-Dependent Toughening in Whisker-Reinforced Ceramics.- Effect of High Temperature Oxidation on the Microstructure and Mechanical Properties of Whisker-Reinforced Ceramics.- The Role of Interfacial Reactions on the Mechanical Properties of Ceramic Brazements.- Fracture Energies of Ceramic-Metal Interfaces.- On the Fracture Behavior and Microstructure of Metal-to-Ceramic Joints.

Physical and mechanical properties of YBa2Cu3O7-δ superconductors

Abstract: The physical and mechanical properties of YBa2Cu3O7−° superconductors are examined. These properties are related to powder preparation method, powder characteristics, sintering behaviour and sintered microstructure. The sintering atmosphere and sintering schedules affect the final microstructure very strongly and determine, in conjunction with starting powder characteristics, the sintered density. The mechanical properties such as Young's modulus, bend strength and critical stress intensity factor (fracture toughness) are measured and related to microstructure as determined by electron microscopy. Control of microstructure by careful powder selection and sintering schedule is seen as key to optimizing the physical and mechanical properties of the material. Finally attention is drawn to fabrication techniques and how these must be optimized in order to realize the mechanical properties which are necessary if these are to be useful as engineering materials. Comparisons between fabrication techniques show that uniaxial powder pressing suffers from limitations in terms of specimen complexity and densification whereas the favoured route, termed viscous processing, gives a more homogeneous microstructure, higher strength and allows near theoretical density to be achieved.

Origin of the 110-K superconducting transition in the Bi-Sr-Ca-Cu-O system.

Abstract: Superconducting critical transitions with an onset at 112 K and zero resistance at 107 K are obtained within the Bi-Sr-Ca-Cu-O system. The synthesis and formation of the 110-K superconducting phase using the 85-K material as a precursor is explained. The 110-K phase grows from the 85-K phase such that the resulting faceted crystal (a pseudomorph) can contain some of the 85-K phase in the core. With such a microstructure our magnetic data can be simply explained. A major structural difference between the 85- and 110-K materials is that the 85-K material can grow (relatively) large single crystals having long-range order whereas the 110-K material has only intermediate-range order (cryptocrystalline) of about 100--200 A.

Structure of mesophase pitch-based carbon fibres

Abstract: The structure of five samples of commercially available carbon fibres with ultra-high modulus produced from mesophase pitch was studied by the complementary techniques of high resolution electronmicroscopy, X-ray diffraction and transverse magnetoresistance effect. The fibres with high strength and elongation to failure were found to be composed of turbostratic carbon structure, which was different from the three-dimensional graphite structure in ultra-high modulus carbon fibres. Transmission electron microscope examination revealed that the mesophase pitch-based fibres with high strength have a basic structure unit with folded sheets arranged nearly parallel to the fibre axis similar to those of high modulus carbon fibres produced from PAN. The present fold structure was suggested to contribute consequently to the lower graphitizability of the fibres and to the strong effects on the fibre strength. By controlling the microstructure, it is expected that the crystallographic as well as the mechanical properties could be improved significantly even from the same kind of precursor materials such as mesophase pitch.

The microstructure of metal–polyimide interfaces

Abstract: We used cross‐sectional transmission electron microscopy techniques to investigate the microstructure of metal/polyimide interfaces. By comparing our results with previously obtained spectroscopy data, we show that the microstructure of these interfaces is strongly related to the tendency of the metal to chemically react with the polyimide at the interface. Cu and Ni do not react with the polyimide and are seen to diffuse inside of the films and form metallic precipitates in the films. Cr reacts with the polyimide at the interface and is thus bounded at the surface, forming a continuous layer on top of the polyimide. Computer simulations are presented that explain the experiment in terms of the different metal–metal and metal–polymer interactions.

Microstructure and Growth Model for Rice‐Hull‐Derived SiC Whiskers

Abstract: The microstructure of silicon carbide whiskers grown from rice hulls has been studied using methods of high-resolution analytical electron microscopy. Small, partially crystalline inclusions (about 10 nm) containing calcium, manganese, and oxygen are concentrated in whisker core regions, while peripheral regions are generally inclusion free. The distinct microphase distribution is evidence of a two-stage growth process in which the core region grows first, followed by normal growth toward whisker sides. Partial dislocations extend radially from the core region to the surface and tend to be paired in V-shaped configurations. Whisker surfaces exhibit microroughness due to a tendency to develop small facets on close-packed planes. The microstructural data obtained from TEM observations are used as a basis for discussion of the mechanisms involved in whisker growth, and a model of the growth process is proposed. The model includes a two-dimensional growth mechanism involving vapor, liquid, and solid phases, although it is significantly different from the classical vapor-liquid-solid (VLS) process of whisker growth.

Effect of Pore Distribution on Microstructure Development: II, First‐ and Second‐Generation Pores

Abstract: A sintering model has been developed to predict the consequences of independently varying the grain growth rate in alumina during final-stage sintering of a microstructure containing both small (first-generation) and large (inter-agglomerate second-generation) pores. The model shows that although it may be thermodynamically favorable to increase the grain growth rate, the kinetics of densification are such that it almost always pays to inhibit grain growth. This conclusion was verified by experiments on undoped, MgO-doped, and ZrO2-doped alumina impregnated with model spherical large pores produced by the burnt-out latex sphere method. A new type of ceramic processing map has also been developed to aid in the selection of the optimum processing conditions for the sintering of ceramics containing large pores.

A study on the microstructure and phase transformation of electroless nickel deposits

Abstract: Electroless Ni-7.4 to 10% P deposits obtained from acidic nickel sulphate baths with sodium hypophosphite as a reducing agent were analysed by transmission electron microscopy, X-ray diffraction and thermal analysis. The deposits could be represented better by a microcrystalline structure composed of 4 to 5 nm fcc Ni-P solid-solution grains rather than an amorphous structure. The deposits also had the (111) texture, which persisted in nickel grains even after phase separation of nickel and Ni3P by heating in the case of the low nickel content, whereas the texture approached the random orientation with increasing phosphorus content. The phase transformation temperature was independent of the phosphorus content.

Influence of Various Consolidation Techniques on the Green Microstructure and Sintering Behavior of Alumina Powders

Abstract: Submicrometer alumina powders, of both standard and narrow particle-size distributions, were consolidated by dry-pressing and colloidal-forming techniques. The resulting green compacts were characterized in terms of pore-size distribution, green density, shrinkage behavior, and sintered density. The interrelationships between powder characteristics, green compact microstructure, and sintering behavior are discussed. There are distinct differences between the characteristics of compacts that were directly consolidated from powder suspensions and those that were dry pressed. Dense microstructures can be achieved at low temperatures using narrow-sized, well-dispersed powders with colloidal-forming techniques.

Magnetic properties and microstructure of AISI 1000 series carbon steels

Abstract: The magnetic properties of a number of specimens of AISI 1000 series plain carbon steels have been measured as functions of chemical composition, microstructure and heat treatment. The results showed that for a given morphology of the carbides the magnetic properties such as coercivity and permeability varied smoothly as a function of carbon content. Coercivity increased with carbon content by 2.0 Oe for every 0.1 wt.% carbon added at low carbon contents while initial permeability decreased by 57% on the addition of 0.2 wt.% carbon in the form of lamellar carbides (pearlite), but by only 21% when those carbides were in the form of spheroidised particles. In all cases the spheroidised specimens were found to be magnetically softer than the lamellar specimens and the difference increased with the amount of carbon present. Grain size did not seem to affect the magnetic properties significantly above a carbon content of 0.2 wt.%, although it was known that grain size is a significant factor in determining magnetic properties in iron alloys with lower carbon content.

Microstructure effects on tensile properties of tungsten-Nickel-Iron composites

Abstract: Controlled processing of heavy alloys containing 88 to 97 pct W resulted in high sintered densities and excellent bonding between the tungsten grains and matrix. For these alloys, deformation and fracture behavior were studiedvia slow strain rate tensile testing at room temperature. The flow stress increased and the fracture strain decreased with increasing tungsten content. The tradeoff between strength and ductility resulted in a maximum in the ultimate tensile strength at 93 pct W. Microstructure variations, notably grain size, explain sintering temperature and time effects on the properties. During tensile testing, cracks formed on the surface of the specimens at tungsten-tungsten grain boundaries. The crack density increased with plastic strain and tungsten content. The surface cracks, though initially blunted by the matrix, eventually increased in density until catastrophic failure occurred. An empirical failure criterion was developed relating fracture to a critical value of the surface crack tip separation distance. Application of the model explains the effects of microstructural variables on tensile properties.

Granular metal films as recording media

Abstract: High‐density recording media require materials with a high magnetization and high coercivity as well as chemical stability, wear, and corrosion resistance. We explore the potential of granular metal films for recording media. Films of Fe granules about 150 A in size embedded in an amorphous SiO2 matrix exhibit coercivities as high as 3 kOe at low temperatures and 1.1 kOe at room temperature, and magnetizations of about 150 emu/g. The methods with which these materials are fabricated, the essential microstructure characterization, and magnetic measurements are described.

Processing Effects in Spray Casting of Steel Strip

Abstract: Spray cast strip of AISI 1026 and M2 has been produced by the Osprey™ process under controlled conditions of deposition. Droplet flight distance was varied over the range 325 to 475 mm and strip was spray cast onto either planar or roller substrates of copper and steel. Substrate surface speed was in the range of 0.02 to 1 m/s, which produced strip of 0.025 to 0.0007 m thickness, respectively, with a width of 0.1 m. Surface condition, microstructure, and extent of porosity in the strip were characterized as a function of distance from top and bottom surfaces. The microstructure of the strip is comprised of three regions —a ‘chill zone’ at the bottom surface consisting of fine grains of ferrite and pearlite with numerous pores; a middle region containing equiaxed or columnar grains, Widmanstatten plates, and fine pores; and a top region made up of equiaxed grains comprising Widmanstatten plates and a few pores. Process variables of primary importance with respect to microstructural integrity and surface condition of the strip are substrate velocity, the surface condition of the substrate, flight distance, and the uniformity of droplet flux in the spray cone. Flight distance determines the amount of cooling of the droplets by the atomizing gas and, therefore, the average temperature of the spray incident on the substrate. Microstructure is determined by convective cooling of the spray, and, to a lesser extent, by the substrate velocity and temperature. The processing conditions required to spray cast strip with a homogeneous microstructure and uniform thickness/surface condition have been established.

Control of microstructure and properties of copper films using ion-assisted deposition

Abstract: The effect of argon ion bombardment on the structure and properties of thick copper films was studied. Primary deposition variables were ion flux, ion energy, substrate temperature, and substrate type. The effects of ion bombardment are profoundly different at high energy (600 eV) as opposed to low energy (62 eV). Trends in crystallographic texture, microhardness, crystallite size, and resistivity are significantly different at different ion energies on all substrates examined. At high energy, the substrate dependence of properties is small while a large dependence is seen at lower energy. This work demonstrates the independence of ion energy and ion flux as control parameters in property modification using ion‐assisted deposition processes.