bluuebunny/crossref_metadata_2025 huggingface dataset:
Vapour Deposited Nanocomposite Thin Films
Authors: Wen L. S.
Published: March 2011

Fundamental principles of nanocomposites are discussed. The basic features of nanocomposites are low dimensionality of their composition components, widespreadness of the electronic interactions between the components and the great variety of microstructure of nanocomposites ranging from high level ordered 3-dimensional periodic structure to stochastically dispersed medium of superfine particle. All these offer much more potential for tailoring the property of materials than by formation of chemical compound or mixture including microcomposites. Vapour deposition enhanced by ion beam and electrical discharge plasma provides a class of versatile processes both for preparing low dimensional components of nanocomposites and for synthesizing nanocomposite film itself. Elements of designing nanocomposite thin films and their preparing by ion beam and plasma enhanced vapour deposition are also discussed. Examples of nanocomposite films are given.
Electrical and Metallurgical Characteristics of PtSix and TiSix/GaAs Schottky Contacts
Authors: He Qian , Jinsheng Luo
Published: March 2011

Electrical properties, metallurgical properties and their relationship of PtSix/GaAs formed by sputter deposition and TiSix/GaAs formed by e-gun multilayer evaporation have been studied. It has been found that TiSix/GaAs contacts exhibit excellent Schottky electrical propcrties and good metallurgical stability after RTA (975°C , 12 sec) but some interface unstability and degradation of electrical properties after conventional FA (800°C ,20 min). The electrical and metallurgical properties of PtSix/GaAs contacts begin to degrate after annealed at 500°C.
Chemical Stability of Vb2 and ZrB2 with Aluminum
Authors: Halperin L. E. , Kolawa E. , Fu Z. , Nicolet M-A.
Published: March 2011

The chemical stability of boride thin films with aluminum is investigated. Only two diborides, VB2 and HfB2 have a positive heat of reaction which makes them potential candidates for thermodynamically stable diffusion barriers between Al and Si. Thin films of VB2, and ZrB2 for comparison, prepared by rf sputtering of composite targets were chosen for this study. Multilayer samples of these borides and aluminum were investigated by differential scanning calorimetry to determine if, according to calculations, a reaction between Al and the borides takes place, and to measure the heat of reaction. We find that an exothermic chemical reaction occurs between ZrB2 and Al and that an exothermic crystallization reaction takes place in the VB2 and Al sample. The reaction products were determined using X-ray diffraction.
Multilayer Metallization Structures in a Gate Array Device Shown by Cross-Sectional Transmission Microscopy
Authors: Gong S. F. , Hentzell H. T. G. , Robertsson A.
Published: March 2011

A multilayer metallization structure in a gate array circuit has been investigated by cross-sectional transmission electron microscopy. Microstructures of thin films, interfaces, contacts, dislocations and step coverage are revealed. Good step coverage was observed when polyimide was used as an insulator between two metal layers.
Formation of Cosi2-Shallow Junctions By Ion Beam Mixing and Rapid Thermal Annealing
Authors: Niewöhner L. , Depta D.
Published: March 2011

Formation of CoSi2 using the technique of ion implantation through metal (ITM) and subsequent appropriate rapid thermal annealing is described. Silicide morphology is investigated by SEM and TEM. SIMS and RBS are used to determine dopant distribution and junction depth. Self-aligned CoSi2/n+p diodes produced in this technique are presented.
Deposition of Tungsten Silicide Barrier Layers and Tungsten in Rectangular Vias
Authors: Cale Timothy S. , Raupp Gregory B. , Jain Manoj K.
Published: March 2011

Diffusion-reaction analysis of a two step process in which a tungsten silicide barrier layer is deposited in a rectangular trench by low pressure dichlorosilane reduction of tungsten hexafluoride followed by a complete tungsten fill by low pressure hydrogen reduction of tungsten hexafluoride reveals that high step coverage and high deposition rate can be readily achieved with logical selection of process parameters. This fact, coupled with the potential for accomplishing these deposition steps in the same single wafer reactor, suggests that this two step process may offer a high throughput alternative to blanket tungsten deposition by silane reduction.
Characterization of the Al/RuO2 Interface Upon Thermal Annealing
Authors: Vu Quat T. , Kolawa E. , Nicolet M-A.
Published: March 2011

We have characterized the Al/RuO2 interface after annealing at temperatures in the range 450° C-550° C for durations up to several hours by backscattering spectrometry, cross-sectional transmission electron microscopy, and electrical four point probe measurement of specially designed structures. The electrical measurement yields the specific contact resistance of the interface by applying a transmission line type model developped for this purpose. An interfacial aluminum-oxygen polycrystalline compound is shown to grow with annealing temperature and duration, with a concurrent reduction of a thin layer of RuO2. However, the specific contact resistance between Al and RuO2 is found to decrease with annealing duration at 500°C. This last result indicates that the interfacial reaction does not lead to an insulating interface as could have been expected if the growth were pure and dense A12O3.
The Effects of SI Addition on the Properties of AICu Films used in Multilevel Metal Systems
Authors: Wilson S. R. , Weston D. , Kottke M.
Published: March 2011

This paper reports a systematic study of the properties of Al(Cu 0.5-1.5%) and Al(Cu 0.5-1.5%, Si 0.5-1.5%)alloys. The effects of deposition temperatures ranging from room temperature to 475°C were studied as well as whether the films were deposited on Ti-W or SiO2. The Cu and Si profiles were measured as well as the presence of Al2Cu and Si precipitates. The effects of post deposition bake treatments are also discussed.
Low Temperature Processing for Multilevel Interconnection and Packaging
Authors: Lu T.-M. , McDonald J. F. , Dabral S. , Yang G.-R. , You L. , Bai P.
Published: March 2011

The future high density multilevel interconnection and packaging requires that the combination of the insulator and conductor layers has a low RC value. Thermal stress and diffusion during processing are issues of great concern in the high density multilevel structures. The problem can be alleviated by a proper choice of materials and processes that do not require high temperature. In this paper we propose to use parylene and its derivatives (dielectric constant 2.3–2.6) as the possible interlayer dielectrics and Cu (bulk resistivity ∼1.7 μ Ω-cm) as the conductor. Parylene can be vapor-deposited and cured at room temperature. The metallization of Cu has been achieved at room temperature using the newly developed partially ionized beam deposition technique. This technique has been shown to grow high quality metal films with low resistivity at low substrate temperatures. The interaction between Cu and parylene, including adhesion and diffusion, is also discussed.
The Effect of Aqueous Chemical Cleaning Procedures on Schottky Contacts to N-Type Gaas
Authors: Kniffin M. L. , Helms C.R.
Published: March 2011

The effect of interfacial oxides and impurities left by aqueous chemical cleaning procedures on the n-type Schottky barrier heights of various metal-GaAs contacts have been examined as a function of annealing temperature. The as-deposited barrier heights of metals which are expected to be reactive with respect to the native oxides of GaAs (Mn, Cr, Al and Ti) were the most sensitive to variations in the residual oxide thickness. Omitting the final oxide etch from the cleaning sequence resulted in a 50 to 60 meV reduction in the as-deposited barrier height of these metals. However annealing these contacts at temperatures as low as 175 °C results in a barrier height that is independent of the initial surface clean. In contrast, for metals which are expected to be unreactive with respect to the native oxides of GaAs (Ni, Au, Cu and Ag) the pre-deposition cleaning procedure had little effect on either the as-deposited or the annealed Schottky barrier heights.
Deposition of Tungsten Boride by Ion Beam Sputtering
Authors: Meyer F. , Bouchier D. , Stambouli V. , Gautherin G.
Published: March 2011

Refractory metal compounds, such as nitrides or borides, are attractive candidates for diffusion barrier between silicon and aluminium in VLSI technology. We studied tungsten boride films deposited on silicon (100) by ion beam sputter deposition (IBSD).

The tungsten boride films were prepared by sputtering a W2B5 target by argon ions with energy ranging from 0.5 to 2keV. The substrate temperature was varied from room temperature to 630°C. Finally, the films were patterned by selective wet etching in order to characterize the resulting Schottky diodes. We observed that a boron loss occurs during deposition, probably due to the backscattering of sputtered boron on previously deposited W atoms. By in situ AES analysis, we verified that a 5 nm thick layer acts as a diffusion barrier for silicon up to about 630°C, for all deposition conditions. The films properties were found to depend weakly on the primary ion energy and on the substrate temperature. All the films have resistivity at room temperature in the range of about 250 µΩ cm. The measured density, in the range of 12 g/cm3, is very close to that of WB2 bulk material, while the intrinsic stress of the films remains compressive and in the range of -lGPa. This value is notably lower than what we measured for pure tungsten prepared under similar deposition conditions.
Effect of Residual Stress on Si-Consumption During W-Deposition by LPCVD
Authors: Lee S. H. , Lee J. J. , Kum Dong-Wha
Published: March 2011

The effect of stress on W-deposition at low pressure by Si-reduction of WF6 has been studied on patterned wafers utilizing cross-section SEM and cross-section TEM. Si-consumption and encroachment formation at the Si/Si02 interface was analyzed as a function of the oxide thickness, which changes the residual stress of the Si-substrate beneath the SiO2-layer. At the edge of the SiO2-layer, significant enhancement of W-deposition was observed from the early stage of W-metallization. Penetration of W into the Si-substrate beneath the edge showed strong dependency upon the oxide thickness, while penetration along the SiO2/Si interface (i.e. encroachment) did not. It has been analyzed that early stage of W-deposition was strongly affected by residual stress in the Si-substrate, and contact between WF6 and Si will be much easier through porous W-film and the W/Si interface, where the existence of microvoids is expected.
The Dependence of Aluminum/Tungsten Reaction on Crystalline Phases of Cvd Tungsten
Authors: Harada Y. , Onoda H. , Madokoro S.
Published: March 2011

The reaction between Al and CVD-W films has been studied. Al/α-W/Si and Al/β-W/Si structures were prepared by deposition on different Si substrates by changing deposition conditions using silane reduction of tungsten hexafluoride, followed by Al-Si-Cu alloy film sputter deposition. The sheet resistance of Al/α-W/Si structure is higher than that of Al/β-W/Si structure after 500°C annealing. RBS measurements show that the W diffusion into Al occurs in both structures after annealing, and the reaction between α-W and Al takes place easily compared with that between β-W and Al. This causes the sheet resistance difference. The activation energies for the W diffusion into Al, however, are almost the same in both structures. When CVD-W films are exposed to air after removal from the reactor, the sheet resistance of β-W film increases according to the exposure time, while that of α-W film does not. AES measurements indicate that the β-W film absorbs more oxygen than the α-W because of the difference of grain structures. The resistance increase of β-W film is caused by the oxygen that is absorbed from air. Our results indicate that the oxygen in the β-W layer suppresses the W diffusion into Al. Once the reaction begins, however, the diffusion into Al does not depend on crystalline phases of CVD-W.
Annealing of Amorphous Ni-Nb/Cu Overlayer Films - Thermal Groove Kinetics
Authors: Farrens S. N. , Perepczko J. H.
Published: March 2011

Recent studies have shown that sputter deposited amorphous NixNb1−x (60≤×≤75) alloy films are effective diffusion barriers for operation at temperatures up to 6(X) °C[1]. The thermal stability of the amorphous films has been established on Si and GaAs substrates and may be modified by interactions wilji polycrystalline metal overlayer films. In the current work a detailed microstructural examination by cross-sectional TEM was performed on the annealing behavior of 50 nm polycrystalline Cu films on amorphous Ni60Nb40. Specifically, the development of grooves at the intersection of grain boundaries in the Cu film with both the free surface and the amorphous Ni60Nb40 base was monitored to evaluate the low temperature interfacial diffusion processes. Based upon measurements of the groove dimensions and dihedral angle during vacuum annealing at 450 °C, the surface diffusion coefficient of Cu was determined as 7.4 × 10-20 m2/sec and the surface energy for Cu derived from groove kinetics was in good agreement with other reported determinations. In addition, the grain boundary grooves that were present at the Cu/amorphous Ni60Nb40 interface in the as-deposited condition were observed to be eliminated during annealing. Again, by following the kinetics of groove healing the interfacial diffusivity was determined to be of the order of 10-28m2/sec at 500 °C and the interfacial energy for the amorphous film/Cu surface was estimated to be ≥ 340 mJ/cm2. The benefits of utilizing amorphous Ni-Nb alloys as underlays to retard thermal grooving and electromigration failure in copper arc discussed.
Blanket and Selective Copper CVD from Cu (Fod)2 For Multilevel Metallization
Authors: Kaloyeros Alain E. , Saxena Arjun N. , Brooks Kenneth , Ghosh Sumanta , Eisenbraun Eric
Published: March 2011

As the focus of integration technology inevitably shifts from the present very large scale integration (VLSI) to ultra large scale integration (ULSI) schemes, thus leading to continuous decrease in circuit dimensions, the limitations of present multilevel metallization technologies become increasingly important. Because of the appreciably higher speeds and more complex multi-functional layering involved in the newest ULSI circuits, the electrical resistance and capacitance of presently used interconnects and their electromigration and stress resistance stand as major limiting factors to signal processing throughput. In this paper, some recent results achieved by the present investigators in their studies of blanket and selective low-temperature metal-organic chemical vapor deposition (LTMOCVD) of copper for potential use in multilevel metallizations in ULSIC’s are presented. The films were produced at 300–400°C in atmospheres of pure H2 or Ar from the β-diketonate precursor bis(6, 6, 7,7, 8, 8, 8-heptafluoro-2, 2-dimethy1-3, 5-octanediono)copper(II), Cu(fod)2. The films were analyzed by x-ray diffraction (XRD), Rutherford Backscattering (RBS), Auger electron spectroscopy (AES), scanning electron microscopy (SEM), energy-dispersive x-ray spectroscopy (EDXS), and four-point resistivity probe. The results of these studies showed that films deposited on metallic substrates were uniform, continuous, adherent, highly pure, and exhibited very low resistivity, as low as 1.8 μΩcm for films deposited in pure H2 atmosphere. Preliminary investigations of selective LTMOCVD of copper showed that selectivity is indeed possible, but is a function of a wide range of parameters that include reactor geometry, substrate type and temperature, working pressure, type of carrier gas, and precursor chemistry.
A Microstructural Investigation into the Effect of the Ambient Atmosphere on Chromium/Polyimide Interfaces
Authors: Peddada S.R. , Robertson I.M. , Birnbaum H.K.
Published: March 2011

This paper describes the effect of the ambient atmosphere (air, vacuum and deuterium) during thermal cycling on chromium/polyimide (Cr/PI) interfaces. Cross-section TEM has been employed to reveal the interface microstructure and morphology. The extent of interdiffusion across the metal/polyimide interface was determined by Energy Dispersive Spectroscopy in the STEM. The nature of the mechanical failure was identified by SEM and the locus of failure determined by Auger Electron Spectroscopy. It was observed that in the Cr/Cu/Cr/PI/Si system, tensile cracks form in the metal layers that originate at the Cr/PI interface after thermal cycling in any of the ambient atmosphere. Also, after annealing, the Cr/PI interface remains sharp, with no significant diffusion of Cr across the interface, irrespective of the ambient atmosphere.
Applied Mechanics of Materials in Conservation Research
Authors: Mecklenburg Marion F.
Published: March 2011

Much of the damage found in cultural and artistic objects is not chemical in nature but results from mechanical responses to stimuli such as changes in temperature, relative humidity, impact, and vibration. Analytical tools of engineering mechanics are available that allow us both to diagnose existing problems as well as to predict the effects of future potential hazardous conditions for many objects. A systematic approach of applying engineering principles to cultural objects requires two fundamental steps: 1, determining the mechanical properties of the constitutive material found in objects, and 2, developing analytical procedures that determine the overall effect of the individual material responses to various stimuli on the object as a whole. The individual material properties are typically defined as the yield and ultimate strengths, the elastic modulus, and the strains to yield and failure.

For the vast proportion of cultural objects, the materials are organic, and their mechanical properties are dramatically altered by environmental factors such as changes in temperature and relative humidity.

One of the most successful analytical techniques is Finite Element Analysis (FEA) using the digital computer. This method will allow one to numerically model an object, to mathematically induce environmental changes as well as determine the mechanical effects of these changes on the object modeled.
Ion Beam Analysis of Pigments
Authors: Cho Barbara , Baum Joanna , Revesz P. , Taft W.S. , Mayer D. , Mayor J.W.
Published: March 2011

We have analyzed single and multiple layer paint samples to evaluate 3 MeV external beam proton induced X-ray emission (PIXE) for elemental analysis of inorganic pigments. The results are compared to those from energy dispersive electron microprobe analysis and Rutherford Backscattering Spectrometry (RBS). The advantage of PIXE is that the protons' penetration depth of 100 microns is more than 25 times greater than that of 20 keV electrons and 10 times greater than 3 MeV alpha particles, thus allowing analysis of relatively thick samples of up to 100 microns. The proton beam is passed into the atmosphere (external to the vacuum system) through a thin polymer film, and the beam area on target is 1 mmz. Electron microprobe and RBS require vacuum compatible samples; therefore, the pigments were painted on silicon wafers. Calibration was obtained from metallic thin-film samples of known thickness. The cross calibration of the three analytical techniques allowed evaluation of external PIXE analysis of paint films. We suggest that this nondestructive method is suitable for elemental analysis of drawings and paintings provided that further studies indicate no long term damage is caused.
Laser Spectroscopy of Materials Used in Paintings
Authors: Larson Londa J. , Shin Kyeong-Sook Kim , Zink Jeffrey I.
Published: March 2011

A wide variety of natural resins, waxes, gums, drying oils and proteinaceous materials used on paintings are photoluminescent. The photoluminescence spectra of these materials are reported and discussed. The application of this technique towards the identification of these materials is considered. Both bulk materials and films prepared from selected bulk materials were studied and a comparison is made between the bulk and film samples. Temperature and excitation wavelength studies are reported and discussed for several of the samples.
Electron and Optical Microscopy of Prehispanic Mural Paintings
Authors: Magaloni Diana , Aguilar Miguel , Castaño Victor
Published: March 2011

In 1984, archaeologists discovered an important group of mural paintings at the site of Cacaxtla, Mexico. Research has been undertaken to analyze the Prehispanic pigments and the painting techniques employed in these paintings. The present work is focused on the use of colors in these paintings by means of optical microscopy (OM) and transmission electron microscopy (TEM). The stratigraphic structure of painting layers support the presence of an organic binding media. In addition, Maya blue is for the first time described physically by TEM.
The Use of Epoxy Resins for Stone Consolidation
Authors: Selwitz Charles M.
Published: March 2011

An overview on the causes and methods of treatment of stone deterioration is presented. The reasons for and prejudices against epoxy resins for stone consolidaton are described in terms of achieving deep penetration, improvement in mechanical strength and good water repellancy without the inhibition of water vapor transmission. Early work which failed to understand the nature of epoxy curing in solution is outlined, and more recent research, where this problem has been solved, is discussed.
Toward a Better Understanding of B72 Acrylic Resin/Methyltrimethoxysilane Stone Consolidants
Authors: Wheeler G.S. , Shearer G.L. , Fleming S. , Kelts L.W. , Vega A. , Koestler R.J.
Published: March 2011

B72 acrylic resin/methyltrimethoxysilane (YMTMOS) mixtures are frequently employed as consolidants for deteriorated limestones, sandstones and marbles- The addition of B72 to MTMOS imparts adhesive properties to the consolidant but it is not known to what degree the B72 affects the reactions which MTMOS must undergo to form a solid polymer network. This paper examines the following chemical, physical, and mechanical properties in order to better understand B72/MTMOS systems: 1. viscosity 2. vapor pressure 3. reaction mechanism and kinetics 4. chemical nature of polymer solids 5. rupture moduli of polymer solids and 6. rupture moduli of stone/consolidant composites.
Contour Scaling on Building Facades - Dependence on Stone Type and Environmental Conditions
Authors: Wendler Eberhard , Klemm Dietrich D. , Snethlage Rolf
Published: March 2011

Contour scaling is often observed on building facades, especially built from clay-rich sandstones. The paper shows that a soluble salt enriched zone and a decrease of the flexural strength below the stone surface can be detected even if a damage is not yet visible. A computer simulated wetting-drying process demonstrates that the mean humidity maximum is situated below the surface. Its depth coincides with the depth of the salt maximum and strenth minimum.
Cathodoluminescence Signature of White Marble Artefacts
Authors: Barbin Vincent , Ramseyer K. , Burns S. J. , Decrouez D. , Maier J. L. , Chamay J.
Published: March 2011

The cathodoluminescence characteristics of more than 500 white marble samples from known classical quarrying sites and surrounding areas in Greece, Turkey and Italy were analysed to develop a rapid and low-cost method for the characterization of white marbles. In most cases, the observed cathodoluminescence colors, intensity and intensity distribution form a distinct “cathodomicrofacies” which is commonly unique for a given area, quarry or parts of a quarry.

In cases where the cathodomicrofacies is common to more than one quarrying area, the stable isotope signature of the white marbles provides an effective complement to cathodoluminescence, and allows additional distinctions between marbles to be made.

The study of field samples from ancient quarrying areas can identify the source of white marble used for ancient sculptures and buildings. This new approach has been successfully tested on ancient marble sculptures and sarcophaguses from the collection of the Art and History Museum in Geneva.
Dynamic Studies of Materials Using the Environmental Scanning Electron Microscope
Authors: Doehne Eric , Stulik Dusan
Published: March 2011

Dynamic studies allow the observation of microscopical changes of materials over time as various factors alter an object. Using this methodology, processes important in art conservation and archaeology such as the wetting and drying of consolidated and unconsolidated building materials or the corrosion of metals from air pollutants can be studied in situ and in tempora. The development of the Environmental Scanning Electron Microscope has made it possible to videotape these dynamic processes at nearly the same resolution limits as traditional SEM technologies without elaborate sample preparation. Experiments examining salt crystallization, shrinkage in adobe, and lead corrosion illustrate the value and applicability of the new E-SEM technology.
Painterly Ceramics in Classical Athens and Renaissance Italy
Authors: Kingery W. David
Published: March 2011

Fired clay vessels began to be produced in the Near East about 8,000 years ago; these vessels were utilitarian, undecorated, fired at a relatively low temperature and seem to have been derived from brick-making practices. By about 6,000 B.C., pottery making was a well developed craft and the use of slip coatings, ocher red and black decoration with control of oxidation-reduction during firing, impressed designs, rouletting, manganese oxide and spinel black pigments, coil and slab construction, burnishing, joining, paddle and anvil shaping, carving, trimming and preparing clays by decanting a suspension were widely known [1]. By the fifth millennium, these techniques had become quite sophisticated and were used to produce polychrome wares and glossy surfaces. Painted and glazed designs were confined to decorative motifs appropriate to a particular technique and culture.
Ceramic Imagery in Ancient Near Eastern Literature
Authors: Polinger Karen
Published: March 2011

Ancient Near Eastern literature includes numerous metaphors, similes, and other figures of speech referring to ceramics. This paper presents selected examples of Sumerian, Akkadian, Egyptian, and Biblical texts using clay, empty or filled vessels, potsherds, potters and the tools of their trade, and potters′ quarters. By examining systematically for the first time the literary, art historical, and archaeological contexts for ceramic imagery, new light may be shed on the role and meaning of ceramics in the ancient Near East. Among the topics considered are: (1) the importance of ceramics in creation imagery; (2) the nature of ceramic death and destruction imagery; (3) ceramic imagery with cornucopial connotations; and (4) literary perceptions of clay, pottery, and the status of potters. The material assembled in this study adds significantly to the evidence gleaned from stylistic and technical analysis of ancient Near Eastern ceramics.
Statistical Analysis of Lead Isotope Data in Provenance Studies
Authors: Reedy Terry J. , Reedy Chandra L.
Published: March 2011

Tracing artifacts to ore sources is different from assigning ore samples to time epochs. Until now, archaeometrists working with lead isotopes have used the ratio methods developed by geochronologists. For provenance studies, however, the use of composition data (the fraction of each of the four isotopes) leads to fewer arbitrary choices, two standard types of plots (labelled ternary and canonical variable), and a consistent method of discriminant analysis for separating groups of samples from different sources.
Use Technologies: An Ethnoarchaeological Study of Kalinga Pottery
Authors: Aronson Meredith , Skibo James M. , Stark Miriam
Published: March 2011

It is difficult to assess the relative importance of technical and non-technical factors in inferring modes of technological decision-making in prehistory. Examination of pottery use technology among the Kalinga using both ethnoarchaeological material and laboratory analysis demonstrates the importance of not only technical (physical properties or functional), but also behavioral or social aspects of technological choices. Kalinga consumers may select pots for functional superiority, or for reasons of village allegiance. Explaining the resulting pattern in the material record requires attention to both technical and behavioral aspects of the pottery technology.
A Compositional and Microstructural Study of Korean Celadon Glazes of the 11th to 15th Centuries
Authors: Newman Richard
Published: March 2011

Celadons--stonewares with pale green or greenish-blue glazes--have a rich and varied history in ancient China that begins in the Eastern Han period (A.D. 20-220) and extends nearly 1500 years [1]. The initial development of celadon wares in Korea probably dates to the late 9th century [2,3]. The zenith of production was in the llth-12th centuries, during the Koryŏ dynasty (918-1392); celadons continued to be produced into the 15th century. In form and type, the earliest Korean celadons were clearly based on Chinese models, although by the middle of the Koryo period uniquely Korean forms and decorative techniques had been developed, notably the use of white and black inlays. During the Koryŏ period, celadons were probably produced exclusively for court circles and for use in Buddhist temples. Some 270 Koryŏ period celadon kilns have been found to date. The greatest concentration (about 240) occurs in Chllla province in the south; the major areas of production were around Kangjin and Puan.
Electron Microprobe and Petrographic Analyses of Prehistoric Hohokam Pottery to Deter. Mine Ceramic Exchange Within The Salt River Vallty, Arizona
Authors: Abbott David R. , Schaller David M.
Published: March 2011

Ceramic analysis with an electron microprobe and thin-section petrography are used to investigate prehistoric exchange among the Hohokam of the Salt River valley, Arizona. These complimentary techniques can be useful for resolving the special problems that arise when studying ceramic exchange over short distances.
Research on the Techniques of Making Pottery Figurines of the Qin Army
Authors: Qu H.J. , Cheng Z.H. , Wu Xiao Jie
Published: March 2011

A description of the excavations of the Qin pottery army is given first. Analyses of the raw materials are reported. The construction techniques of the soldiers and horses are detailed separately. Lastly, analysis and reconstruction of the firing technology and post-fire paints are presented.
Non-Destructive Analysis of Ancient Chinese Bronzes Utilizing Industrial Computed Tomography
Authors: Avril Ellen B. , Bonadies Stephen D.
Published: March 2011

Industrial computed tomography was used to study eight Chinese bronzes from the collection of the Cincinnati Art Museum. With industrial CT two different types of images can be formed, the digital radiograph (DR) which produces a twodimensional image of the object and computed tomography (CT) which takes a crosssectional slice. A further advancement discussed is the use of General Electric's Digital Replica™ method to create a three-dimensional reconstruction of the object which enables one to view interior surfaces and to dissect joins. The paper discusses the numerous advantages of the industrial CT over conventional radiography.
Estimating Original Firing Tempieraiure in Low Fired Prehistoric Ceramics
Authors: Feathers James K.
Published: March 2011

The river valley clays used for prehistoric pottery throughout much of Eastern North America require a nonplastic additive, or temper, to improve their workability and reduce drying shrinkage. During the Late Prehistoric (roughly after 900 AD) crushed shell was added as temper along most of the river valleys of the Midwest and along portions of the Gulf and Atlantic coasts.
The Use of Acryloid B-72 in the Treatment of Archaeological Ceramics: Minimal Intervention
Authors: Koob Stephen P.
Published: March 2011

The treatment of archaeological ceramics, whether on site or in the laboratory, can be effectively carried out with the use of one synthetic material, Acryloid B-72. This acrylic copolymer provides excellent properties for the strengthening or consolidation of weak and friable ceramics, and also makes an excellent adhesive. The strength and durability of B-72 make it a suitable adhesive for a broad range of ceramics, from low-fired earthenwares to china and porcelain.

Acryloid B-72 is easily prepared on site, and for most applications can be dissolved in acetone. Various concentrations are recommended and application can be modified to suit local conditions and needs. Flaking and fragile fragments can be consolidated insitu(if dry) and lifted for individual attention in the laboratory. Soluble salts may be extracted from consolidated ceramics by soaking or using poultices.

The well-known stability and reversibility of Acryloid B-72 allow for easy retreatment, or subsequent repair of additional fragments.
Chemical Characterization of Roman Glass Vessels, Enamels and Tesserae
Authors: Henderson Julian
Published: March 2011

Chemical characterization of Roman glass vessels, enamels and tesserae has revealed compositional relationships between enamels and tesserae including the use of high magnesia red and orange glass, normally considered to have gone out of use hundreds of years earlier. The conservative use of glass recipes over a 300 year period is reflected in the compositions; the results of mass-production versus more restricted production are discussed.
Fabrication of Platinum-Gold Alloys in Pre-Hispanic South America: Issues of Temperature and Microstructure Control.
Authors: Handwerker Carol A. , Lechtman Heather N. , Marinenko Ryna B. , Bright David S. , Newbury Dale E.
Published: March 2011

Platinum and platinum-gold metallurgy was fully developed by smiths in the Esmeraldas-Tumaco Pacific coast area of present day Ecuador and Colombia long before the arrival of Europeans in South America and centuries before platinum metallurgy became practicable in the Western world. Using gold to sinter together nuggets of native placer platinum, then alternately working and annealing the resultant solid, these South American smiths produced hard, fairly homogeneous platinum-gold alloys of a range of colors for fabrication into items of adornment, and small tools, such as needles, tweezers, awls, and fishhooks.

The microstructures and compositions of sintered Pt-Au objects from La Tolita, Ecuador, and of experimentally simulated Pt-Au alloy samples were analyzed using new electron microprobe microanalysis (EPMA) techniques and data from the Pt-Au phase diagram in an effort to determine the fabrication temperatures used by Pre-Hispanic South American smiths. A comparison of EPMA results from the simulated materials with the corresponding results from the La Tolita Pt-Au objects suggests that the Pt-Au objects were never heated as high as 1100°C and probably never contained a liquid phase. As illustrated by this comparison, the qualitative and quantitative information provided by these new digital acquisition and display techniques far exceeds what conventional line scan and x-ray dot maps could provide.
Correlation of Laboratory Results with Observations on Long-Term Corrosion of Iron and Copper Alloys
Authors: McNeil M. B. , Mohr D. W. , Little B. J.
Published: March 2011

The data base for compounds produced during long-term corrosion of iron and copper objects is reviewed. Compounds are identified that occur in long-term but not in short-term corrosion. Where possible, the formation of these compounds is explained or at least rationalized. An effort is made to discriminate those compounds whose formation depends on microbiological action from those forming abiotically.
Conservation of the Windover (8Br246) Textiles
Authors: Humphrey Bruce , Gardner J.S. , Andrews R.L. , Adovasio J.M. , Strong D.E.
Published: March 2011

The excavations at the Windover Bog site (8BR246) in 1986 and 1987 yielded 87 specimens of technologically sophisticated textiles and other perishables from 37 human burials. The assemblage currently represents the oldest known textiles from this hemisphere. Unfortunately, microscopic examination has demonstrated that substantial cellular degradation has occurred in these artifacts. In fact, these items are but the dimmest reflections or more accurately skeletons of their former predepositional states. Although traditional consolidants ensured a minimum of warpage and shrinkage with subsequent freeze drying, they produced an undesirable surficial film. Additionally, the resultant products were extremely brittle and required further treatment. To this end, several leading authorities suggested the testing of Parylene gas phase polymer technology on the Windover specimens. The senior author introduced Parylene gas phase technology to the conservation field in 1984. Since that time, numerous evaluation programs have been undertaken at major institutions. Important artifacts as well as extremely ancient natural history materials have been successfully treated utilizing Parylene technology [1]. This paper specifically addresses the application of Parylene gas phase polymer technology to the consolidation and preservation of the unique textile materials recovered from the Windover site. Major areas of discussion are: historical background, early conservation efforts, evaluation and decision to use Parylene technology, properties of the Parylene family of polymers, the method of deposition and treatment, and final conclusions on the consolidation of the treated textiles.
Permanence of Washi(Japanese Paper) (Part II)
Authors: Inaba Masamitsu , Sugisita Ryuitiro
Published: March 2011

The change of degree of polymerization (DP), crystallinity and extent of oxidation during deterioration of Washi (Japanese paper) were studied. The extent of decrease of DP of cellulose in the Washi samples correlated with their acidity. The higher DP of cellulose in Washi fiber compared to that in wood fibers contributes to its permanency. It is reported that partial recrystallization of the amorphous regions in fibers during ageing results in a decrease of flexibility of the paper. From measurements of X-ray diffraction, less recrystallization of Kozo, Mitsumata and Gampi papers occurs during ageing treatment. This fact also contributes to the persistence of the strength of Washi through time. From measurements of infrared spectra of Washi samples, the amount of oxidation seems to be minimal.
The Mechanics of the Deterioration of Surfaces
Authors: Berger Gustav A. , Russell William H.
Published: March 2011

Paint layers on a stretched canvas or solid support present complicated behavior and failure patterns. The cracks, cups, blisters, and sagging commonly found in paintings give ample evidence of the detrimental effects of environmental changes on a composite of mechanically dissimilar materials. Under variations in stress caused by environmental conditions, the materials are inelastic and non-linear individually and collectively are anisotropic. The authors have conducted extensive biaxial tests on dozens of painting samples under variable stress, strain, relative humidity, and temperature [1,2,3,4].
Use of Network Analyzer and Coaxial Probe to Determine Complex Permittivity
Authors: Blackham David
Published: March 2011

A vector network analyzer combined with an open ended coaxial probe provides a way to make non-destructive measurements of complex permittivity. These measurements can be made on both solids and liquids.

Many authors have done work on using an open ended coaxial line for making these measurements[1][2][3]. They have presented different techniques for modelling the coaxial probe. This paper does not focus on the area of modelling, but deals instead with the use of a vector network analyzer and coaxial probe in making measurements. To enhance measurement accuracy, the technique described adapts a calibration technique currently in use in vector network analysis.

An HP 8720B vector network analyzer was used for the development and measurements presented in this paper.
The Design of a TM10 Resonant Cavity Microwave Applicator as a Preheating Andcrosslinking Die for Pultruded Composites
Authors: Ghaffariyan S.R. , Methven J.M.
Published: March 2011

Pultrusion is the only continuous process available for the manufacture of fibre reinforced thermosetting composites. It its simplest form it requires that dry reinforcement inthe form of continuous rovings or fabrics is pulled through a shallow bath of resin and then through a heated metal die wherein the resin crosslinks to a rigid network. The rate of manufacture (pulling speed) depends on two factors; the rate of heat transfer to and through the composite by conduction from the (heated) die wall and the rate of heat generated internally by the (exothermic) crosslinking reaction.
Review of the French Activity in Microwave Control and Processing of Materials
Authors: Bolomey Jean-Charles , Metail Jean-Pierre
Published: March 2011

Materials or, more generally, industrial products may be processed and/or controlled by means of microwave techniques. This paper presents a brief overview of the recent french activity related to such industrial applications of microwaves. For some of these applications, microwave techniques are already currently used while, for some others, studies are still conducted at a research and development level.
Anomalous Behavior of Heterogeneous Materials at Microwaves Frequencies: Introduction to Fractional Derivatives in Electromagnetism
Authors: Heliodore F. , Cottevieille D. , Mehaute A. Le
Published: March 2011

The present note introduces new trends in electromagnetic spectroscopy in complex media.When an electromagnetic wave propagates in heterogeneous media, some questions arise about both physical meaning and validity range of the traditional analysis. The aim of our advanced research is related to the generalisation of Maxwell's equations able todescribe both homogeneous and heterogeneous media from an unique point of view.
Theory of Microwave Effects on Atomic Diffusion in Sintering: Basic Considerations of The Phenomenon of Thermal Runaway
Authors: Kenkre V. M. , Skala L. , Weiser M. W. , Katz J. D.
Published: March 2011

We present the results of our recent studies of the possible origin of the reported increase in sintering efficiency brought about by the application of microwaves. We study the phenomenon of thermal runaway in ceramic materials undergoing microwave heating and present a theory on the basis of a simple temperature-time equation. The nonlinear evolution inherent in the equation arises naturally from physical considerations. The theory isapplied to experimental observations reported on several different materials including silica, alumina, strontium titanate, zinc oxide and iron oxide, and shown to be in good agreement with the data.
Microwave Sintering of Oxides
Authors: Aliouat M. , Mazo L. , Desgardin G.
Published: March 2011

Microwave sintering of oxides has been studied, owing to its great flexibility for thermal treatments, which may influence in particular the microstructure and the electrical properties of the so sintered material. In order to point out the influence of the structure and electrical properties we studied the microwave sintering : i) of insulating complexe oxides with the perovskite structure, ii) of close packed structure such as spinelsand iii) of high Tc superconductors. The differents behaviours of those materials in a microwave field are compared and discussed.
Microwave Sintering Technology for the Production of Metal Oxide Varistors
Authors: McMahon G. , Pant A. , Sood R. , Ahmas A. , Holt R.T.
Published: March 2011

A microwave sintering technology has been developed for the production of metal oxide varistors. The electrical properties (leakage current and non-linearity coefficient) of the microwave sintered devices were found to be comparable to those obtained for conventionally sintered varistors of identical composition. Additionally, the reference voltages were greater (by a factor of two) and the biaxial moduli of rupture were higher for the microwave sintered specimens. These differences have been attributed to the smaller grain size associated with the microwave sintered specimens.
Microwave Sintering of Zirconia-Toughened Alumina Composites
Authors: Kimrey H. D. , Kiggans J. O. , Janney M. A. , Beatty R. L.
Published: March 2011

Microwave sintering possesses unique attributes and has the potential to be developed asa new technique for controlling microstructure to improve the properties of advanced ceramics. 1–6 Because microwave radiation penetrates most ceramics, uniform volumetric heating is possible. Thermal gradients, which are produced during conventional sintering because of conductive and radiative heat transfer to and within the part, can be minimized. By eliminating temperature gradients, it is possible to reduce internal stresses, which contribute to cracking of parts during sintering, and to create a more uniform microstructure, which may lead to improved mechanical properties and reliability. With uniform, volumetric temperatures, the generation of nonuniform particle/grain growth due to temperature gradients and associated sintering gradients can be regulated.
The Properties of Alumina Sintered in a 2.45 GHz Microwave Field.
Authors: Patterson Mark.C.L. , Kimber Robert M. , Apté Prasad S.
Published: March 2011

A method has been developed to reproducibly sinter high purity alumina (>99.8%) to densities in excess of 98% of theoretical. Sintering times of between 6 and 120 minutes have been investigated and a uniform grain structure is only obtained with sintering times greater than 30 minutes.

Microwave sintering produces a product with a smaller, more uniform grain structure witha more narrow size distribution. The alumina is also tougher than the conventionally sintered material.

When scaled—up to sinter batches of 400 grams, an energy consumption of 3.8 kWh/kg is required, which is estimated to be a 90% savings over conventional sinteringin an electric resistance furnace.
Microwave Processing of Silicon Nitride
Authors: Tiegs T. N. , Kiggans J. O. , Kimrey H. D.
Published: March 2011

Microwave sintering of Si3N4—based materials showed improved densification as compared to samples heated conventionally under similar conditions. Accelerated nitridation of Si in the microwave furnace to produce Si3N4 was also observed. Dense Si3N4, annealed by microwave heating, exhibited enhanced grain growth; however preferential coupling of the microwave power to the grain—boundary phases in the present experiments resulted in their degradation.
Microwave Sintering of Nanocrystalline TiO2
Authors: Eastman J. A. , Sickafus K. E. , Katz J. D. , Boeke S. G. , Blake R. D. , Evans C. R. , Schwarz R. B. , Liao Y. X.
Published: March 2011

Nanocrystalline TiO2 compacts having initial approximate mean grain sizes of 14 nm and approximate green densities of 70% of theoretical were sintered by short-time exposure in a 2.45 GHz microwave cavity to maximum temperatures of 800, 1000 or 1200 ºC. Sample densities were measured before and after exposure to microwaves using Archimede's method. Transmission electron microscopy and x-ray diffraction were utilized to monitor grain growth and phase changes. Rutherford backscattering was used to monitor any changes in oxygen stoichiometry. The results of this study indicate that enhanced densification behavior is obtained for microwavesintered samples relative to samples sintered using conventional pressureless-sintering techniques.