Research and Scholarship

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the Manufacture of Architectural Terra Cotta at the Plant of the Corning Terra Cotta Company Corning New York
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 1925) Fraser, Orray Thurber
In this paper, the process of manufacture and production of architectural terra cotta will be discussed. The author has spent the past summer of 1924 in the plant of the Corning Terra Cotta Company located in Corning, New York. Here he had an opportunity to observe the various processes of manufacture and help to perform some of them.
Magnetostriction of Magnetite
(Alfred University. Faculty of Ceramic Engineering. Kazuo Inamori School of Engineering, 1954-02-01) Stull, John Leete
The magnetostriction of Fe3O4 was measured, using the strain gauge technique. Two methods were used to measure the magnetostrictive behavior of single crystals and polycrystalline samples as a function of orientation and temperature. The measurements show that magnetostriction does not play an important part in causing a peak in initial permeability in magnetite near its low-temperature transition. Another conclusion is that magnetostriction measurements can be used for this type of material as a tool to detect changes in the direction of easy magnetization.
Semiconductivity in Cadmium Telluride
(Alfred University. Faculty of Ceramic Engineering. Kazuo Inamori School of Engineering, 1958-06) Stull, John Leete
Conventional Hall coefficient and resistivity measurements were carried out in single crystals of CdTe, both "pure" and with added impurities, and in hot-pressed polycrystalline specimens. In most cases, the sign of the current carriers was consistent with the valence of the added impurity. Discrepancies in certain trivalent impurity crystals are explained on the basis of an excess of Cd vacancies. The mobilities for electrons averaged about 200 cm2/v sec, and those of holes about 40 cm2/v sec, both at room temperature. Anomalous changes in resistivity as a function of applied electric field and heat treatment in crystals containing both donors and acceptors were found and investigated. A rough model is developed which accounts for most of the effects observed.
Ceramics in a Liberal Arts Curriculum
(Alfred University, 1960-12) Leach, Richard, B.
The philosophy of education has under gone little change since the founding of the college at Harvard in 1636. The aims of the educators have shifted from the general ends proposed, to "…advance learning and perpetuate it to posterity…”, to educate youth in good manners and to emphasize instruction in the arts and sciences so that the student may “…be fitted for publick employment both in Church and in Civil state."* to a more elaborate means to the same end. The persuit of the Liberal Arts has been an attempt by men to discover by free use of intellectual faculties something of the nature and meaning of the universe and man' s place in it as well as the highest values to which human life can aspire. These eternal truths were to be revealed by the study of Rhetoric, which included Latin and Greek grammar and syntax, Logic; and Philosophy or Metaphysics which was, in effect, a course in psychology, sociology, history as well as philosophy. Entrance to college was based on the ability to read Latin verse and prose, and to decline perfectly nouns and verbs in Greek. The chief emphasis of the education was the acquisition of the tools and discipline of logic to the sages past. The two languages were the media for transmitting of the inherited cultural tradition to posterity. Knowledge of Latin and Greek was the key to the understanding and appreciation of a body of History, Science and Philosophy as well as of literary forms which made up the substance of Western Civilization. This Renaissance ideal, coupled with the concepts of duty and discipline of Puritanism, was the ideal of the leaders of American higher education in the seventeenth century.
Shoji Hamada, Japanese Potter
(1967-06) Weltner, George H.
Now 73 years old, Hamada is considered by many American potters, particularly those of the so-called "California School," to be out of date. Whether he is out of date or not, he was certainly an important influence on pottery as an art form in this country as well as in England. He and his friend and senior, Bernard Leach, the English potter, are still considered by many people to be the two foremost artist-potters in the world. The material available on Hamada-or by Hamada--in English is meager. But such material as there is is scattered and I believe it serves a useful purpose to bring it together. This is not the kind of job that calls for originality. Hamada’s own writing I have quoted exactly as written, though often in a different topical sequence. The material of other writers, Bernard and Janet Leach, Soetsu Yanagi, Hugo Munsterberg and a few others I have paraphrased as well as quoted, but my sources are always acknowledged. My own opinions crop up here and there, particularly at the end. Where they appear, they are clearly identified as mine. Mr. Daniel Rhodes has made invaluable contributions out of his personal experience and knowledge. I would not have dared to tackle this subject if he had not offered to help.
Sodium carbonate vapor firing
(1974) Zamek, Jeff
Anyone who has observed a salt firing knows the white cloud which covers the immediate area with sodium chloride and hydrochloric acid. These pollutants directly and quite dramatically affect the refractories and metals associated with the salt kiln in an adverse way, and in a more subtle fashion affect the ecology of the locale. For these reasons many salt kilns have had to be shut down in urban areas or areas which have stringent pollution laws, expensive anti-pollution devices can be installed, but they are generally not practicable for the studio potter.
Our Alphabet Book: Promoting Personal Relationships Between Children with Disabilities and their Nondisabled Peers
(1990-04-18) DeAngelo, Maria A.; Sutton, Cynthia; Morgan, Theodore; Howard, Benjamin
'Our Alphabet Book' was created because negative attitudes do not allow interaction between children with disabilities and their peers to occur naturally, and so it must be planned. This book provides one opportunity for natural interaction between students to occur in the classroom.
Polyethylene Glycol Binders for Advanced Ceramic Processing
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 1992-02) Walker, William J., Jr.; Reed, James
An amorphous polyethylene glycol compound (PEG20M) and polymer blends containing PEG20M as a major component were evaluated as binder systems for the dry pressing of spray-dried ceramic powders. Comparisons were made with two types of plasticized polyvinyl alcohol systems commonly used in ceramics. PEG20M and PEG-based systems resulted in lower viscosity slurries and higher green density compacts than the polyvinyl alcohol based systems. Green strength of specimens prepared with PEG20M was between that of specimens prepared with the two grades of polyvinyl alcohol. Sintered density using PEG20M was equal to that from one grade of polyvinyl alcohol and higher than the other. Thermolysis of PEG20M in a compact was an exothermic process and proceeded more rapidly than that of polyvinyl alcohol. A binder concentration corresponding to half coverage of surface adsorption sites in the slurry was seen to be significant in pressing and sintering behavior. Phase separations observed when small amounts of polyvinyl alcohol were added to PEG solutions influenced green strength. The rate of thermolysis of PEG20M in a compact was dependent on specimen geometry and the addition of an antioxidant slowed the process.
Technological Advances of Imaging As Applied to Library Archives
(1995-05-08) Youells, Bernadette D.; Meehan, Laurie Lounsberry; Olshan, Toni; O'Connor, Rima
In this report I discuss the advantages of using digital imaging, its applications, and how much it costs. I also review the necessary hardware and software needed to implement a digital imaging program. The advantages of using digital imaging as a means of storage and retrieval are conservation, preservation, and the increased accessibility of rare and disintegrating items.
Electrically Conductive Ceramic Powders
(New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering., 1999-05) Lu, Yanxia; Giesche, Herbert
Electrically conductive ceramic powders were investigated in this project. There are three ways to produce those materials. The first is doping alkali metal into the titanium dioxides in an inert or reducing atmosphere. The second is reducing un-doped titanium dioxide, forming a non-stoichiometric composition in a hydrogen atmosphere. The third is to coat a conductive layer, reduced titanium dioxide, on an insulating core such as alumina. Highly conductive powders have been produced by all these processes. The conductivity of powder compacts ranged between 10^-2 and 10^0 S/cm. A novel doping process was developed. All samples were doped by a solid-vapor reaction instead of a solid state reaction. Titanium dioxide was doped with alkali metals such as Na or Li in this study. The alkali metal atom contributes an electron to the host material (TiO2), which then creates Ti^3+ ion. The conductivity was enhanced by creating the donor level due to the presence of these Ti^3+ ions. The conductivity of those alkali doped titanium oxides was dependent on the doping level and charge mobility. Non-stoichiometric titanium oxides were produced by reduction of titanium dioxide in a hydrogen atmosphere at 800˚C to 1000˚C for 2 to 6 hours. The reduced titanium oxides showed better stability with respect to conductivity at ambient condition when compared with the Na or Li doped samples. Conductive coatings were prepared by coating titanium precursors on insulating core materials like SiO2, Al2O3 or mica. The titania coating was made by hydrolysis of titanyl sulfate (TiOSO4) followed by a reduction procedure to form reduced titanium oxide. The reduced titanium oxides are highly conductive. A uniform coating of titanium oxides on alumina cores was successfully produced. The conductivity of coated powder composites was a function of coating quantity and hydrolysis reaction temperature. The conductivity of the powder as a function of structure, composition, temperature, frequency and moisture was studied. Three classifications of structure were identified for alkali-doped titanium oxides: 1) Pure titanium dioxide phase with alkali ions located in interstitial positions. 2) The titanium bronze phases. 3) Alkali-doped titanium oxides. Highly conductive powders were obtained in the first and second classifications with conductivity of 10^-2 to 10^0 S/cm. Materials in the third classification had poor conductivity below 10^-3 S/cm. The conductivity of a powder was determined mainly by the grain conductivity and the grain contact conductivity. The present results of impedance spectroscopy suggested that the grain contact resistance was a major factor of the electrical resistance of the samples. The aging effect at different moisture conditions was also caused by an increase of the contact resistance. Both sodium-doped and reduced titanium oxides showed re-oxidation at elevated temperature (above 140˚C) in air, which is most probably caused by oxidizing the Ti^3+ ions under those conditions. Lithium doped titanium oxides did not show this re-oxidation at temperatures up to 200˚C. Theoretical models were applied to describe the effects of porosity, contact configuration and grain surface on conductivity of powder compacts. Percolathion theory was used in the present study to demonstrate the effect of mixtures of conductive and non-conductive powders, which is one of applications for conductive ceramic powders when they are used as filler materials in paper, paints or plastics.
Colloidal Behavior of Clay in Whiteware Suspensions
(New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering., 1999-10) Rossington, Katherine; Cormack, Alastair
This research investigated the colloidal behavior of kaolinitic clay in aqueous suspensions. The foundation of most current clay suspension behavior is based on early studies conducted prior to the application of colloidal concepts in ceramic systems and also when many of the colloidal theories were being developed. Technological advances in colloid science and the application of the theories greatly enhance the interpretation of the clay suspension behavior. Kaolinitic clay is the primary component responsible for the colloidal behavior of in traditional ceramics because the clay accounts for over 90% of the total surface area and active charge sites. The impact of cations and anions on colloidal behavior, specifically the dispersion and coagulation, of a whiteware suspension was examined using rheology and electrophoretic mobility measurements. The results indicate the cations are responsible for coagulating the suspension, including sodium, which has been labeled both a dispersant and a coagulant. The anionic species are responsible for dispersing the clay suspension, but zeta potential is an inaccurate measure of suspension stability. The influence of chemistry changes via cation and anion additions observed in suspensions are also detected in plastic bodies. The plasticity measured by the cohesion stress decreases with increasing cation concentration. It is suggested that the magnitude of the cohesion stress directly influences the formability and stress gradients established duringdrying.
Aqueous Processing of Alumina and Phase Behavior of Polymeric Additives
(New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering., 1999-12) Sundlof, Brian; Carty, William
The goal of this research was to produce ceramic alumina microstructures with controlled porosity attained through the exploitation of polymeric phase separation. In order to accomplish this goal, a fundamental understanding of the aqueous colloidal behavior and sintering of alumina were required. The ability to manipulate the polymeric phase separation process was necessary in order to tailor porosity. For this reason, background information regarding the phase separation process and the parameters associated with its thermodynamic and kinetic properties were essential. The dispersion of aqueous suspensions of two a-aluminas (APA-0.5 and A-16 S.G.), were investigated. APA-0.5 was a high purity powder, and A-16 S.G. had MgO added as a sintering aid and contained relatively high levels of other impurities, most notably Na2O. The APA-0.5 was used as a standard alumina, while the A-16 S.G. represented a common industrial powder. Acids (HCl and H2SO4) and bases (NaOH and NH4OH) were used to adjust suspension pH. HCl was the only electrostatic dispersant found to substantially alter suspension viscosity. The z -potential and critical coagulation concentration (CCC) of electrostatically dispersed with HCl suspensions were measured. A correlation was found between the CCC and the inability of H2SO4, NaOH, and NH4OH to disperse alumina. The inorganic anionic polyelectrolytes examined included sodium silicate, sodium hexa-metaphosphate, and sodium carbonate. Comparisons were made between plots of the different polyelectrolytes (viscosity as a function of dispersant level), as well as between the two aluminas. Rheological phenomena correlated with z -potential measurements, the dissociation behavior of the polyelectrolytes, and the powder surface chemistry. The organic anionic polyelectrolytes examined include the sodium and ammonium salts of poly(methacrylic acid) and poly(acrylic acid), and neutralized citric acid. Comparisons were made between dispersants (viscosity as a function of dispersant level), including effectiveness and general rheological trends. Rheological phenomena were correlated with z -potential measurements, the dissociation behavior of the polymers and the powder surface chemistry. HCl and NH4-poly(acrylic acid), PAA, were used to stabilize alumina suspensions. A dual minima was found in the PAA dispersed suspensions containing MgO. The dispersant level of the first minima was a function of the concentration of sodium, shifting to lower dispersant levels for higher sodium concentrations. The second minima corresponded to the PAA dispersion of alumina. The critical coagulation concentration was measured for suspensions stabilized to a minimum in viscosity via electrostatic (HCl), inorganic electrosteric (sodium silicate and sodium hexa-metaphosphate), or organic electrosteric (NH4- and Napolymethacrylates, NH4- and Na-polyacrylates, and citric acid) dispersants. The salts investigated were the chlorides and sulfates of sodium, magnesium, and calcium. The thickness of the electrical double layer (d) around an alumina particle was calculated as a function of the electrolyte concentration and valence of the counter-ion, using a capacitance model. All of the suspensions coagulated at the same critical d value (~0.96 nm). Estimations of critical coagulation concentration using the critical d values obtained from MgCl2 additions agreed with rheological observations. The dependence of microstructure development on the type of dispersant used in the processing of alumina was investigated. Bulk density, and percent linear shrinkage measurements were used to evaluate the “green” density of pellets slip cast then calcined to 1000°C. Firing temperatures of 1200°C, 1400°C, and 1600°C were used to evaluate the densification process using bulk density and shrinkage measurements. SEM micrographs of pellets fired to 1400°C, polished, then thermally etched, display variations in morphology and grain size. The addition of Na+ ions to the suspensions resulted in abnormal grain growth, the organic component inhibited grain growth, and the inorganic dispersants severely inhibited grain growth. Binary-polymer/solvent and ternary-polymer/solvent interactions were observed using optical microscopy and light scattering (turbidity). The polymers investigated were poly(methacrylic acid) (PMAA), poly(vinyl alcohol) (PVA), and poly(ethylene glycol) (PEG). A ternary mixture design was used to evaluate the dependence of turbidity on polymer concentration. An increase in the degree of polymeric interaction was correlated with an increase in turbidity. The effects of pH, background electrolyte, electrolyte concentration, and temperature on the maximum in turbidity was evaluated using a statistical experimental design. The polymer concentrations, and the ratio of one polymer to another, were found to have the most profound effect on increasing turbidity. The solution pH and electrolyte conditions played important roles in the complexation of PMAA with PVA and PEG. An increase in the solution temperature decreased the turbidity of PMAA-PEG solutions, and increased the turbidity of PVA-PEG and PMAAPVA solutions. Based upon the information gathered, the microstructures developed when dextran sulfate and PEG were added to an aqueous alumina suspension, were the result of polymeric phase separation; the pores of which were thermodynamically stable. Using the knowledge gained from the investigations, a suspension can be processed outside the phase separating region by manipulating the thermodynamic properties of the polymer system. Phase separation can then be induced by changes in the suspension pH, electrolyte level, and temperature. The size, shape and connectivity of the pores can be controlled through kinetics. Although only demonstrated for alumina, the approach could be extended to other systems, providing an easily fabricated sample with tailored porosity.
The History of the Student Senate of Alfred University and its correlation with national issues
(2000-05) Pellicciotti, Michael
The Student Senate has been the student government of Alfred University since 1906. This thesis shows, through a historical record of Student Senate, how national issues correlate with Senate's structure and its issues. The Senate has changed much over the last century, but so has society. Different eras of the past Century have affected the Student Senate and the culture of the student body. It reviews the impact of the World Wars on Alfred and on Senate's leadership. The thesis also examines the Civil Rights movements on campus and the protests during the 1960s and 1970s. It specifically assesses administrative and faculty power through Senate's history and the impact this had in shaping Senate issues.
Are the Pines There Now? An Historical Study of Pine Hill, Alfred University, Alfred, NY
(2000-05) Sloane, Kristin E.
Pine Hill is a tract of land that is used often by Alfred University students and faculty, but its history has not been well recorded. The forest has been mentioned fondly in diaries and memoirs of students and faculty, and the history of its development goes back to 1824. Records show that this acreage has changed in composition from dense forest, to farmland and grazing fields, to a reforested recreational area for the University. Past and present University leaders have shown their dedication to the environment and campus beautification through vast planting and reforesting projects on Pine Hill. Yet, the developmental history of this valued tract has not been reviewed in depth and an accurate map of the current Pine Hill has not been created. Due to the importance of this land to the University, an in-depth historical study of the management of Pine Hill would be an important tool to be used by current students and faculty. The new trail map and discoveries from this study will be presented.
The Oxidation of Diamond
(New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering., 2001-02) Howe, Jane; Jones, Linda
The objective of this project is to develop a fundamental understanding of the oxidation behavior of diamond. Research efforts on oxidation and phase transition of diamond have been undertaken through a combination of experimental and computational approaches. Heat treatments are carried out on CVD diamond film ET100, manufactured by Norton Diamond Film, in a wide temperature (420 to 1500 oC) and oxygen partial pressure range (from 6x10-10 to 95 kPa). Theoretically, surface chemisorption and reconstruction of diamond surfaces are investigated using density functional theory. Taking both oxidation and phase transition into consideration, we propose that diamond can take either one of the two different paths during the heat treatment of diamond in oxygen at elevated temperatures: 1) direct gasification of sp3-bonded carbon; and 2) sp3 to sp2 phase transition (surface reconstruction) first, then gasification of sp2-bonded carbon. Diamond oxidation and phase transition are results of these two competing mechanisms. We further suggest that surface oxygen coverage and temperature are the two most influential factors that govern the surface reaction of diamond. The reaction between oxygen and diamond (111) surface at ambient pressure is summarized as: • Room temperature and 0 % coverage: The (111) surface reconstructs to (2x2) or (2x1) reconstruction. This occurs without any change of the bond character. • Elevated temperature (~ 700 oC to 1500 oC), zero coverage: The bond character of diamond (111) surface changes from sp3 to sp2. Thus, diamond goes through a phase transition and forms amorphous, sp2-bonded carbon. If the temperature reaches 1600 oC or higher, the amorphous carbon graphitizes and becomes crystalline. • Elevated temperature (~ 700 oC and higher), low coverage (up to 20%): Diamond converts to amorphous, sp2-bonded carbon first. Then the oxidation of carbon proceeds, yielding gaseous products CO and/or CO2. • Elevated temperature (~ 500 oC and higher), high coverage (more than 50%): Diamond converts to amorphous, sp3-bonded carbon first. Then the oxidation proceeds, yielding gaseous products CO and/or CO2.
Finite element predictions of residual stress relief in a two-dimensional cantilever beam
(Alfred University. Faculty of Ceramic Engineering. Kazuo Inamori School of Engineering., 2002) Kuang, Lin
Elastic-plastic finite element analyses were performed to predict the residual stress relief in cantilever beam. A script was written to use the commercial finite element code ANSYS to predict residual stress relief by vibratory treatment. Several case studies are performed in which various factors such as driven frequency, excitation amplitude and level of residual stress are changed. The main focus of the current research is to investigate the conditions under which VSR works and the extent of stress relief by VSR. The results from the computer simulation show that resonant VSR (R VSR) and sub-resonant VSR (SUB-R VSR) will relieve residual stress in the beam. The canitlever beam which has max compressive residual stress in top fillet can get the greatest residual stress by R VSR. Also the greater excitation amplitude, the more stress relief.
The Unity Molecular Formula Approach to Glaze Development
(New York State College of Ceramics at Alfred University. Inamori School of Engineering., 2002-02) Quinlan, Brian; Carty, William; LaCourse, William; Earl, David
The study of glazes is inhibited by the complex nature of multiple oxide compositions typically witnessed in industrial and art glazes. This research systematically addresses this complexity issue in multiple glaze compositions consisting of SiO2, Al2O3, CaO, MgO, Li2O, K2O, and Na2O oxides through the use of the Unity Molecular Formula (UMF) approach. The UMF limits for simple glaze compositions are defined for matte and gloss surface development. These limits are defined using Glossmeter, SEM/EDS, XRD, ICP-AES, and Optical Interferometry analytical techniques. Included is the correlation of gloss and surface roughness characterization techniques, which is compared with visual observations in order to define the most accurate surface quantification tool. Also a proposed technique that will define the glass formation boundary is introduced by using the internal standard method of quantitative XRD coupled with ICP-AES. Results show that matte formation, in the glaze systems tested, is either a result of underfiring or devitrification. Also, the proposed glass formation boundary technique has the ability to accurately define the glass formation boundary, but it may only be restricted to use with simple, three component glass compositions. Crystalline phases exhibiting solid solution, found in more complex glaze systems, reduce the accuracy of the technique. Finally, it is demonstrated that the optical interferometer is superior to gloss measurement when quantifying a wide range of glaze surface qualities. Through this approach multi-component glaze systems can be thoroughly analyzed and accurately represented in terms of its development using the UMF approach. The analytical techniques incorporated in this study effectively evaluate the complex glaze systems allowing for further study into more complex systems.
Structure and Stability of Europium Doped B-Alumina Type Phosphor
(New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering., 2002-07) Wu, Zhehua; Cormack, Alastair
BaMgAl10O17 (BAM) has been widely used as the host material for Eu-active phosphors for lamps and display panels. It has a luminescent wavelength ranging from 430nm to 450nm, blue in color. However, there is a degradation problem for this phosphor material: the luminescent intensity decreases and the emission band shifts from blue toward green in color with an increase in application period and annealing procedure of manufacture. The suggestion that the luminescent degradation is related to the oxidation of europium from a 2+ to 3+ oxidation state forms the basis for the first part of this thesis. A computer simulation study of the behavior of europium in BAM (based on the classical Born model description the ionic materials) was carried out. Europium ions were found to prefer different lattice positions depending on their valence state: Eu2+ prefers the BR site in the mirror plane; Eu3+ prefers the Al(2) site in the spinel block. Because there are many other barium hexa-aluminate phases besides BAM and because they can also be used as the phosphor host materials, the phase relationship between these phases and the properties of the Eu dopant in these phases were also investigated, in particular, for the barium-poor phase, Ba0.75Al11O17.25. The barium-poor phase, after doping with Eu2+, shows a broader and shifted emission band compared to BAM. The formation of barium-poor phase has also been proposed as the reason for the observed luminescent degradation in BAM. Calculations on the barium-poor phase were performed to investigate the origin of the emission band differences between it and BAM, and the complete solid solution between them. The coexistence of multiple OBR-distributions in the barium-poor phase was found to be the origin of the observed broader and shifted emission band of Eu2+. Since the hypotheses about luminescent degradation involve phase changes or structural adjustments, molecular dynamics simulations of ion migration were also performed to study the defect and structural changes after the europium oxidation. It was found that Eu3+ ions can migrate from the mirror plane to the spinel block at relatively low temperature, and that Eu2+ ions have a tendency to congregate in BAM.
The Role of Polymer Compatibility in Ceramic Processing
(New York State College of Ceramics at Alfred University. Kazuo Inamori School of Engineering., 2002-09) Kim, Ungsoo; Carty, William
The proper use of multiple polymeric additives in ceramic processing is discussed. First, the use of a polyelectrolyte as a dispersant is studied by looking at the adsorption of various molecular weight PAAs on clay and the effect on suspension rheology. The adsorption of PAA on clay particles is not influenced by molecular weight, but there exists an optimal chain length for minimum viscosity. Secondly, the interactions between polymeric additives in suspensions and during drying are investigated. The phase behavior of polymer systems is studied by Flory-Huggins theory and the interactions in polymer solutions are examined using light scattering and optical microscopy. The results are used to explain the PVA migration behavior. PVA can be stained and its location within the spray dried granule can be observed, verifying the effect of other polymers on binder migration. It is shown that phase separation of polymer systems is the primary reason for the PVA migration. The chain length and functional groups of polymers determine the phase behavior of polymers and in turn the degree of binder migration.
Synthesis Optimization of Aurivillius Phases
(Alfred University. Faculty of Ceramic Engineering. Kazuo Inamori School of Engineering., 2003) Peterson II, Myles S.
The solid state processing, sintering behavior and conductivity of the Bi_{2}Sr_{2}Nb_{2}TiO_{12} Aurivillius phase were studied. The solid-state processing steps were investigated using X-ray powder diffraction (XRD). The in-situ formation of Bi_{2}Sr_{2}Nb_{2}TiO_{12} was measured using high temperature X-ray powder diffraction (HTXRD). Bi_{2}Sr_{2}Nb_{2}TiO_{12}, SrTiO_{3}, two and four-layer Aurivillius phases formed with this in-situ technique.Rietveld refinement was used to characterize the Aurivillius unit cell, and to model four-layer Aurivillius impurities. A weighted residual of 0.14 and a χ2 of 4.5 was obtained. The refined lattice parameters for Bi_{2}Sr_{2}Nb_{2}TiO_{12} were a=3.8927(7) Å, and c=33.1960(9) Å for a body centered tetragonal unit cell with the I4/mmm space group. Rietveld refinement was used to confirm the unit cell of the δ-Bi_{2}O_{3} present in certain samples. The refined lattice parameter for the δ-Bi_{2}O_{3} was a = 5.5747(4) Å with a cubic crystal system and a space group of Fm-3m. A designed statistical study on density and affect of the sintering accelerator Bi_{2}O_{3} was completed. The model had an R2 of 0.93 and a Sy.x of 0.33, and suggested that an optimum sintering temperature was ~1060°C with approximately four weight percent Bi_{2}O_{3} added to the Aurivillius phase. The scanning electron microscope (SEM) and energy dispersion spectroscopy (EDS) were used to investigate the microstructure and identify secondary phases when necessary. The conductivity of Bi_{2}Sr_{2}Nb_{2}TiO_{12} and samples with Bi_{2}O_{3} added to the Aurivillius phase were explored using impedance spectroscopy (IS). The addition of Bi_{2}O_{3} greatly enhanced the conductivity values of the Bi_{2}Sr_{2}Nb_{2}TiO_{12} to the magnitude of the current ionic conductor standard, yittria stabilized zirconia.

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