Ceramic Materials Commons^™

Fire Fossils: Biomineral Infrastructures In Untangling Climates, Tanmayee More

Masters Theses

Diatoms drift, sediments sink, wildfires generate their own weather. Lightning strikes can blast sand into glass, and microscopic organisms do the same in the cold recesses of the ocean. What alchemies and metabolisms catalyze space, time, and energy? What are the thermodynamics of infrastructure in Climate Change?

Places, materials, and beings are afterimages. Through alchemical experiments, and multi-scalar imaging, I develop simulations of wildfires, and their profound, reverberating effects. In this thesis, a glass-meets-landscape experimental process enters these obscured conditions and renders new material relations for the built environment.

Waste Illuminates Worlds: Printed Modular Lamp Design Based On Brick And Clay Tile, Yechen Zhu

Masters Theses

The building industry in the New England area is often in a state of entropy, with abandoned brick buildings contributing to urban decay. The recycling rate of brick and clay tile wastes generated by construction and demolition is only 12.2%, meaning the majority is sent to landfills. The expansion of landfills can lead to significant environmental and community challenges, including increased traffic from waste transport, habitat destruction, ecosystem degradation, and contributions to climate change. Specifically, the Bethlehem landfill in New Hampshire, which is planned to undergo a 5.71-acre lateral expansion through 2026, has already encountered issues such as leachate spills …

Processing & Properties Of Zirconium Carbide Manufactured By Ceramic On-Demand Extrusion, Clare Sabata

Masters Theses

"This research focuses on the development of a zirconium carbide (ZrC) paste for use in material extrusion direct ink write additive manufacturing (AM) followed by the pressure less densification of ZrC and the mechanical and thermal characterization of the resulting ceramics. A highly loaded, aqueous paste was developed using commercial ZrC powder ball milled to ~1 μm. Optimal dispersant, binder, and solids loading were found by rheological characterization. The paste composition consisted of 46-47 vol% ZrC, 43.5 vol% distilled water, 8.1 vol% dispersant, and 1.6 vol% binder. A yield stress of ~8 Pa allowed for shape retention upon removal of …

Intrinsic Mechanical Properties Of Zirconium Carbide Ceramics, Nicole Mary Korklan

Masters Theses

“This research focuses on the processing and mechanical properties of zirconium carbide ceramics (ZrC_x). The first goal of this project was to densify near stoichiometric (i.e., x as close to 1 as possible) and nominally phase pure ZrC_x. The maximum stoichiometry achieved for the ZrC_x (C/Zr ratio of 0.92) was measured using gas fusion analysis. Hot pressing was used to obtain dense ZrC_x. Archimedes was used to determine the relative density of hot pressed ZrC_x at > 95%. Scanning electron microscopy (SEM) was used to determine the overall microstructure of the hot pressed …

Processing, Microstructure, And Properties Of Engineered Diboride Structures, Connor Charles Wittmaier

Masters Theses

"The mechanical properties and processing parameters of boride ceramics in foam and laminate architectures were evaluated. The ceramic reticulated foam was produced through a polymer substrate replication technique and the hardness and compressive strength were tested. The laminate structure was tested to evaluate the flexure strength and work of fracture as a function of temperature.

The foam architecture was produced using a TiB₂ slurry coating on a polyurethane reticulated foam preform. Foams sintered to 2150⁰C displayed an average grain size of 8.9 ± 7.3 µm, and a hardness of 17.3 ± 2.4 GPa. Crush testing foams were sintered at …

Liquid Phase Sintering Of 20bi(Zn₀.₅Ti₀.₅)O₃-80batio₃ Dielectrics With Bismuth-Zinc-Borate And Bismuth Borosilicate Glasses, David I. Shahin

Masters Theses

"Dielectrics in the Bi(Zn₀.₅Ti₀.₅O₃-BaTiO₃ system (specifically 20BZT-80BT, in mol%) are promising candidates for high energy density capacitor applications due to broad temperature-dependent dielectric constant maxima and a relatively field-independent permittivity. Bulk samples require sintering temperatures of greater than 1180ºC to reach useful densities. Due to incompatibility of Bi with low-pO₂ processing, BZT-BT-based multilayer capacitors must utilize noble metal electrodes that resist oxidation during sintering. Sintering temperatures must be reduced to allow use of less expensive electrode materials (Cu, etc.). This work studies the reduced temperature sintering behavior and dielectric properties of BZT-BT sintered with 30 Bi₂O₃-30ZnO-40B₂O₃ and 50Bi₂O₃-25B₂O₃-25SiO₂ (mol%) liquid …

Processing And Properties Of Zrb₂-Zrsi₂ Matrix Composites Reinforced With Continuous Sic Fiber, Benjamin John Bowin Lai

Masters Theses

"The research presented in this thesis focuses on the processing, microstructure, and mechanical properties of ZrB₂-based composites. The main goal was to develop a process that incorporates high strength continuous SiC fiber in a ZrB₂-based matrix. In order to achieve this, the densification, microstructure, and mechanical properties of ZrB₂-ZrSi₂ monolithic ceramics were characterized along with various SiC fiber reinforced ceramic matrix composites (CMCs) utilizing the same matrix.

There were two main areas of study in this thesis. The initial study demonstrated that additions of ZrSi₂ into a ZrB₂ ceramic increases densification at significantly reduced processing temperatures ≤1600ºC). This study revealed …

Microstructure And Mechanical Properties Of Silicon Carbide-Titanium Diboride Ceramic Composites, Derek Scott King

Masters Theses

"The microstructure, hardness, fracture toughness, Young's modulus, strength and Weibull modulus of silicon carbide-titanium diboride (SiC-TiB₂) ceramics were studied. First, SiC-TiB₂ ceramics with 15 vol.% TiB₂ particles were processed using two green processing methods, spray drying (ST) and ball milling (SiC-15TiB₂). In addition, SiC-TiB2 ceramics with TiB₂ contents ranging from 0 to 100 vol.% were produced to determine a TiB₂ content that produced the best combination of mechanical properties. From spray drying, segregation of the TiB₂ particles in ST led to a granule-like microstructure and spontaneous microcracking in the final ceramic. In ceramics containing 20 and 40 vol.% TiB₂, the …

Sputter Deposition Of Thin-Film Capacitors Onto Low Temperature Co-Fired Ceramic Substrates, Jack Murray

Masters Theses

"Single layer thin film capacitor structures were fabricated on the surface of low temperature co-fired ceramic (LTCC) substrates using sputter deposition. The capacitor structures had areas between ~10⁴ µm² to ~10⁶ µm² and featured ~200 nm Al or Pt electrodes with 150-1500 nm Al₂O₃ dielectric layers. Impedance analysis and current-voltage testing were carried out to determine the effect of electrode material and dielectric thickness upon capacitor performance. Capacitance values for devices with Al electrodes ranged from ~10 to ~700 pF, depending on capacitor area and dielectric thickness, and the fit to expected values was better than devices with Pt or …

The Properties And Structure Of Tin Phosphate Glasses Modified With Other Oxides, Jong Wook (Austin) Lim

Masters Theses

"The main objective of this research was to evaluate the properties and structures of glasses from the stannous (SnO) phosphate system for possible use in low temperature optical applications. Glasses in the binary xSnO-(100-x)P₂O₅ system (50 ≤ x ≤ 70) were prepared and their thermal and optical properties were evaluated. Differences in glass transition temperatures (T_g) measured here and reported in the literature were explained by differences in the residual water content in the glasses, as determined by infrared spectroscopy. In general, increasing the SnO content of the binary glasses increased the refractive index and the glass transition …

Sintering And Microstructural Effects On Mechanical Properties Of Zirconium Carbide-Tungsten Cermets, Melissa M. Giles Craft

Masters Theses

"Zirconium carbide-tungsten cermets were prepared by in situ reaction sintering a mixture of zirconia and tungsten carbide. Tungsten is a refractory metal with a melting point of 3422⁰C; however, its mechanical strength decreases significantly with increasing temperature. One approach to improve the elevated temperature strength is to add ceramic particulates to the matrix. Zirconia and tungsten carbide were compacted and then reacted and sintered in a single step by heating to 2050⁰C. The resulting stoichiometric zirconium carbide-tungsten cermet had a relative density greater than 96%. Cermets with two different grain sizes were produced by altering the final sintering temperature. Sintering …

Properties Of Alkaline-Resistant Calcium-Iron-Phosphate Glasses, Jiawanjun Shi

Masters Theses

"The physical properties and alkaline corrosion resistant properties of calcium-iron-phosphate glasses were studied. The addition of Fe₂O₃ decreases the thermal expansion coefficient and increases the glass fiber's Young's modulus in comparison with the addition of CaO. Bulk glass dissolution behavior in alkaline Lawrence solution was studied by weight loss experiments, Raman spectroscopy, and analytical scanning electron microscopy. The corrosion of glass powder in NaOH solution was studied by X-ray diffraction, infrared spectroscopy and high pressure liquid chromatography. The results show that the dissolution rate decreases when the phosphate chain length decreases. Calcium oxide can improve the glass durability in high …

Iron Phosphate Glass For The Vitrification Of Ineel Sodium Bearing Waste And Hanford Low Activity Waste, Robert Douglas Leerssen

Masters Theses

"The current study investigates the feasibility of using iron phosphate glass for the immobilization of nuclear wastes that have limited solubility in the current borosilicate glass used for vitrification. These wastes contain elements such as sulfur and phosphorus, which have proven problematic (causing phase separation at >1 wt%) for vitrification in borosilicate glasses, as well as having a high soda content (50-75 wt%) which also limits wasteloading"--Abstract, page iv.

Iron Phosphate Glasses As A Potential Nuclear Waste Disposal Medium, Melissa G. Mesko

Masters Theses

”Phosphate glasses containing large amounts of Fe₂O₃ (up to 43wt%) were studied to determine their potential suitability as nuclear waste disposal glasses for high level radioactive wastes containing large concentrations of iron oxide, phosphate, and fluoride compounds. Glass formation and chemical durability was the prime focus of this study, while properties such as density, thermal expansion, dilatometric softening temperature, and devitrification temperature were examined as well. It was found that large amounts of simulated nuclear waste material (up to 44.4wt% Cs₂O or 37.5wt% SrO) could be incorporated into the base iron phosphate glass while retaining …

Glass Formation And Properties In The Sm₂O₃·Al₂O₃·Sio₂ System, Erik M. Erbe

Masters Theses

"The purpose of this investigation was to develop a samarium containing aluminosilicate glass with properties suitable for use in the treatment of rheumatoid arthritis. Microspheres made from these compositions would be neutron activated to produce radioactive Sm-153 which has beta-particle energies suitable for treating rheumatoid arthritis as well as appropriate gamma-ray emission for nuclear imaging. The properties of Sm₂O₃ · AI₂O₃ · SiO₂ glasses containing 10 to 25 mole% Sm₂O₃ were evaluated as a function of composition. The density, refractive index, thermal expansion coefficient, and microhardness increased with increasing Sm …

The Effect Of Phosphate Additives On Alumina, Alumina-Calcia, Alumina-Silica Refractory Castable Systems, Sukendro Widjaja

Masters Theses

The effects of the addition of phosphate chemicals to Al₂O₃, Al₂O₃-CaO, and Al₂O₃-SiO₂ systems have been studied concentrating on selected dry and fired properties. The various refractories evaluated were formulated from all alumina aggregate systems based on 1) a mix of tabular and calcined fine aluminas, 2) a combination of calcium aluminate cement bonded-tabular and calcined fine aluminas, and 3) an alumina aggregate-silica fume mixture. Specimens were vibration-cast, dried at 110°C and fired at 1450°C. It was found that each system has different property responses to different …

Sessile Drop Studies Of Aluminum On Sapphire, Ke Wen K. Li

Masters Theses

A sessile drop technique employing a drop placement method has been used to investigate the wetting behavior and interfacial phenomena between aluminum and single crystal α-alumina. Measurements were made under a flowing mixture of H₂ and He atomsphere from 1200°C to 1600°C. Acute contact angles decreased continuously in all cases during the 8-hour experimental time. Neither the oxygen partial pressure of the flowing gas nor the orientation of the single crystal alumina substrate affected the contact angles, but the shapes of crystals grown at the substrate-metal interfaces were dependent on the orientation of the substrate surface to some extent. …

Processing And Characterization Of Ceramic Fiber Reinforced Porous Matrix Composites, Wen-Chiang Tu

Masters Theses

"The development of ceramic fiber reinforced ceramic matrix composites has been shown to be a promising approach for high toughness ceramic materials. The purpose of this work was to develop a new ceramic matrix composite(CMC) system based on a porous mullitic matrix reinforced with ceramic fibers. Unidirectional alligned fiber reinforced mullitic matrix composites were fabricated by a filament winding process. Prepregs were laminated and thermal processed in air. SEM fractographs of the composites were characterized and related to the observed load-deflection behaviors under 3-point flexure. The fracture surface expositions changed from extensive fiber tear-out to limited fiber pull-out as the …

Fabrication And Mechanical Property Analysis Of A Transparent, Glass Fiber Reinforced Polymer Matrix Composite, James R. Olson

Masters Theses

"A "transparent” composite was produced by reinforcing poly(methyl methacrylate) (PMMA) with unidirectional borosilicate glass fibers. Composites with 40 volume percent fiber had a modulus of rupture of 600 MPa which is six times greater than that of pure PMMA. Young's modulus for the same composite was 18 MPA which is nine times greater than the 2 MPa measured for pure PMMA. Work of fracture was 110 kJ/m² or more than double the 45 kJ/m² required to fracture pure PMMA. The optical transmission of the composite with 30 volume percent fiber was approximately 40 percent through a 10 mm …

The Effect Of Additives On Properties Of Pfn-Pfw Dielectric Materials, Weih-Min Liao

Masters Theses

"The purpose of this study was to investigate the effect of processing and additives on the properties of the Pb(Fe_1/2Nb_1/2)O₃-PB(Fe_2/3W_1/3)O₃ solid solutions. The basic composition was 70 m% Pb(Fe_1/2Nb_1/2)O₃ and 30 m% Pb(Fe_2/3W_1/3)O₃. The additives used were MnO, PbO and ZnNbO₆. Pressed compacts were sintered over the temperature range 900'C to 1050°C for 1 to 5 hours.

The influence of processing and composition on the properties was determined by measurement of density, shrinkage, dielectric constant, dissipation factor and …

The Effect Of Excess Lead Oxide On The Sintering Characteristics And Dielectric Properties Of Lead Magnesium Niobate Ceramics, Dyllan Jye-Lun Hong

Masters Theses

"The effect of lead oxide additions on sintering characteristics and dielectric properties of ferroelectric Pb₃MgNb₂O₉ based capacitors was studied. The basic dielectric compositions were formed by solid state reaction. Densification was studied as a function of PbO content over the temperature range 900 °C to 1000 °C for sintering times one to six hours depending on the amount of additive, and the sintering temperature.

Weight loss, density and shrinkage measurements of each composition were made in order to relate the effects of the excess PbO additions on the densification. The dielectric and electrical properties were …

An Apparatus For The Measurement Of Dc Electrical Conductivity And Seebeck Coefficient Of Semiconductors As A Function Of High Temperature And Oxygen Partial Pressure, George Francis Carini Ii

Masters Theses

"A computer controlled apparatus for the measurement of dc electrical conductivity and Seebeck coefficient as a function of temperature and oxygen partial pressure has been developed. Thermocouples are in electrical and thermal contact with the ends of the specimen bar. This allows both Seebeck and four-wire electrical conductivity measurements to be made in situ. Environmental enclosure of the specimen allows measurements over a range of oxygen activities from 1 to 10^-18 atm. A discussion of the measuring technique with schematics of the apparatus and data retrieval system is made. Results for measurements in selected oxide ceramics are compared to …

The Development Of Glass-Ceramic Matrix Composites And The Crystallization Of Two Glass-Ceramic Matrices, William M. Carty

Masters Theses

"In order to develop ceramic matrix composites for high temperature applications, two glass-ceramic matrices, one an yttrium aluminosilicate (YAS), the other a magnesium aluminosilicate (cordierite), were chosen as possible matrix compositions. Two separate sets of experiments were performed. Specimens were hot pressed and heat treated then analyzed for the crystallization products and C.T.E. Specimens were also prepared containing commercially available ceramic fibers and coated ceramic fibers to investigate fiber/matrix interactions and the effect of fiber additions on the crystallization of the glass matrices. DTA was employed to approximate the crystallization temperature of the glasses and to determine the effect of …

Glass Fiber Reinforced Polycarbonate Composites, Wen Ching Hu

Masters Theses

"The purpose of this work was to develop a transparent glass fiber reinforced polymer composite material which is superior to the transparent unreinforced thermoplastic in mechanical properties but similar in optical clarity. Polycarbonate matrix composite specimens containing 0 to 40 wt% SK-12 glass fiber were studied, with mechanical and optical properties determined as a function of glass fiber content. The mechanical properties -- flexural strength and elastic modulus increased with increasing glass fiber content. The optical properties -- transmission and transparency decreased with increasing glass fiber content. The factors which influence the mechanical and optical properties were investigated"--Abstract, page ii.

Causal Factors In The Hydration Susceptibility Of Periclase Aggregates, Chao-Min Cheng

Masters Theses

"The findings presented in this thesis are the result of a study of the hydration mechanism of pre-calcined periclase aggregates. It is hoped that these findings will provide the means to develop an economical, stable and hydration resistant layer on the surface of periclase aggregates by coating with appropriate chemical systems.

In the conduct of this study two sources of commercially obtained materials, Steetley 323, and China metal 90-10, supplied by the Quigley company, were characterized and treated with different concentrations of boron-containing water suspensions in order to impose an altered layer which would resist hydration.

Variables affecting hydration investigated …

Property Survey Of Y₂O₃-Al₂O₃-Sio₂-MₓoY Glasses, Amy Lee Applewhite

Masters Theses

"The purpose of this work was to investigate the properties of Y₂O₃-Al₂O₃-SiO₂-M_xO_y glasses. Many M_xO_y components were tested, but TiO₂ and B₂O₃ proved the most interesting. Glasses containing 5 to 25 wt % TiO₂ were melted and found to have improved chemical durability and a higher refractive index and density than the eutectic Y₂O₃-Al₂O₃-SiO₂ starting glass. These glasses could be crystallized to form an opaque glass ceramic. Glasses containing B₂O₃ were formed by exchanging SiO₂ with B₂O₃ while holding the Y₂O₃ and Al₂O₃ content constant. The density, hardness, refractive index, transformation temperature, softening temperature …

The Interfacial Phenomena Of Liquid Copper Of Sapphire Substrates, Jenq Liu

Masters Theses

"The wetting behavior of liquid copper on the sapphire is effected by the crystallographic orientation of the solid surface, the oxygen partial pressure, and the temperature. Each of these influences has been studied by the sessile drop technique, over the oxygen partial pressure range from 10^-2 to 10^-20 atm at temperatures of 1373°K, and 1523°K. The effect of oxygen partial pressure on the liquid copper surface energy follows the Gibbs Langmuir Law.

The crystallographic orientation of the sapphire surface causes variations in the contact angle. This is more significant for higher oxygen partial pressure, but is eliminated at …

Influence Of Oxygen Activity On The Lattice Parameters And Thermal Expansion Of Mg And Sr-Doped Lacro₃, Sutham Srilomsak

Masters Theses

"Lanthanum Chromite, when used as the fuel cell interconnector material is exposed to extremely different oxygen activities on its two surfaces. In addition, it must also form coherent boundaries with the fuel electrode (anode) and air electrode (cathode) layers. In order to accomplish these functions the acceptor doped LaCrO₃ must not only be chemically stable over large oxygen activity ranges, but also have good thermal expansion coefficient of match with both the anode and cathode. Therefore, the objective of this study is to investigate these requirements for Mg and Sr doped LaCrO₃. The study was divided into …

The Effect Of Oxygen Partial Pressure On Oxygen And Carbon Incorporation In Czochralski Grown Single Crystal Silicon, Paul Shane Carter

Masters Theses

"The study herein detailed was made to determine the effect of varying the oxygen partial pressure of a Czochralski type crystal pulling furnace using conventional hardware and remelt silicon on the level of incorporated oxygen and carbon in the single crystal. The oxygen partial pressure was measured by a zirconia type oxygen sensor and controlled by additions of hydrogen or carbon dioxide to the argon purge gas. The oxygen and carbon incorporation measurements were made by the Fourier Transform Infrared (FTIR) method, using the American Standard for Testing Materials (ASTM) standard calibration.

During the study boules which were zero dislocation …

An Investigation Of The Low Voltage Failure Mechanism In Multilayer Ceramic Capacitors, Christopher John Brannon

Masters Theses

"Enhanced leakage current was induced into multilayer ceramic capacitors by the introduction of micro-cracks. These cracks extended from the surface through the electrode layers and were formed by means of thermal shock. The capacitors were then exposed to a low voltage bias and a humid atmosphere. Results indicated that a simple electrolytic solution mechanism may be responsible for the increased conduction, and that the proposed dendritic growth mechanisms may be more complex than necessary"--Abstract, p. ii