Materials Science and Engineering Commons^™

Anomalous Diffusion Of Carbon In A 70/30 Iron-Nickel Alloy, L. R. Chapman, D. A. Powers, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Sessile Drop Studies Of Gallium On Alumina, Timothy John Snyder

Masters Theses

"The liquid-vapor and solid-vapor interfacial energies of the system Ga-Al₂O₃ were determined by the sessile drop technique. The interfacial energies were found to decrease with increasing temperature and P₀₂.

A maximum liquid-vapor interfacial energy of 581 ergs/cm² was found for a clean sessile drop at 1227°C. Values for Γ₀, the excess concentration of oxygen, were calculated for both the liquid-vapor and solid-liquid interfaces. The work of adhesion between molten Ga and Al₂O₃ was found to increase with decreasing P₀₂ with a maximum of 576 ergs/cm² occurring …

Effects Of Varying Oxygen Partial Pressure On Molten Silicon-Ceramic Substrate Interactions, And Oxygen Partial Pressure Measurements Of Silicon Sheet Production Facilities, P. D. Ownby, Harold V. Romero

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Glass Surfaces Then And Now, Norbert J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

A reservoir of efficient instrumentation capable of detailed and quantitative exploration of glass surface features is now available in the face of the recognition of their crucial importance for both surface and bulk properties as well as performance. Yet it may be instructive to glance at what had been learned about glass surfaces by investigators before the advent of these intricate tools. Among such earlier findings are the recognition of the altered composition and structure of the surface layer, the extension of this disturbance to considerable depth, the effect of surface structure on adsorption, adhesion, wetting, finishing, etc. and on …

Measurement Of The Wear Properties Of Metallic Solids With A Falex Lubricant Testing Machine, Edward Boyd Hale, Chun-Ping John Meng, Ronald A. Kohser

Physics Faculty Research & Creative Works

A modified Falex Lubricant Testing Machine has been used to determine wear properties of metallic solids. In particular, wear mass loss, wear volume loss, wear rates, and other parameters have been determined for a basic steel, as heat treated and after ion implantation. Wear rate improvements of more than an order of magnitude were found in a nickel-chrome steel (SAE 3135) implanted with 2.5x10¹⁷ N⁺₂/cm². Wear tests were conducted with a cylinder-in-groove geometry in a mild lubricating oil with loads greater than 540 N, which corresponded to pressures which exceeded 10⁸N/m^{2 …}

Phaseautomodulation In Magnesium, Alexander Aning, Tetsuro Suzuki, Manfred Wuttig

Physics Faculty Research & Creative Works

No abstract provided.

Chemical Corrosion Of Ag Films On Glass, Hyun Soo Park

Doctoral Dissertations

"The chemical corrosion of chemically, vacuum and sputter deposited Ag films on an aluminoborosilicate and a soda lime glass was investigated in wet HCl and saturated water vapor as a function of concentration, temperature and time. The higher corrosion resistance of chemically deposited Ag films in comparison to evaporated or sputtered Ag films is attributed to their lower microvoid density and higher adhesion strength. Ag films on the more chemically durable aluminoborosilicate glass had a higher corrosion resistance. Furthermore, films which received a moderate thermal annealing (80 to 140° C) or were deposited on a glass surface washed with HN0 …

Conduction Polarization In Sodium Germanate Glasses, Akira Doi, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

Only one thermally stimulated depolarization current (TSDC) peak was found in germanate glasses containing from 0.19 to 32.5 mol% Na₂0, whereas comparable silicate glasses exhibit two such peaks. Equations are developed showing that the distortion of the equilibrium Na⁺-ion distribution by an applied electrical field produces a polarization in general agreement with the observed TSDC peak. It is proposed that the TSDC peak is due to dc conduction.

Structure And Properties Of Neodymium Chromite, David Charles Hitchcock

Masters Theses

"Pure, accepton and Al doped NdCrO₃ were prepared by an organo-metallic process.

The crystal structure and lattice parameters were determined by x-ray diffraction. All compositions were orthorhombic Pbnm.

Pellets were pressed from powders of each composition and sintered to high density in a reducing atmosphere. When a small amount of Fe was substituted for Cr, the powder could be sintered in air.

Electrical conductivity for acceptor doped NdCrO₃ varied from about 1 (ohm cm)^-1 at room temperature to about 10 (ohm cm)^-1 at 900°C, about two orders of magnitude higher than the electrical conductivity of the …

Model For Evaporation Of A Grain‐Boundary Phase, Manfred Wuttig, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The surface profile which develops in the vicinity of a grain boundary precipitate in the course of evaporation is calculated. It is shown that the presence of the grain boundary precipitate affects the profile significantly if the product of the width of the grain boundary precipitate and the ratio of the evaporation rates of the unperturbed surface and the grain boundary precipitate is larger than one. Copyright © 1981, Wiley Blackwell. All rights reserved

Autooscillations In Zinc, Manfred Wuttig, Alex Aning, Tetsuro Suzuki

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

The Inert Gas Effect On The Rate Of Evaporation Of Zinc And Cadmium, P. C.S. Wu, Thomas J. O'Keefe, Fred Kisslinger

Materials Science and Engineering Faculty Research & Creative Works

An experimental study has been made to investigate the effect of argon and helium on the rate of evaporation of zinc and cadmium under one atmosphere pressure at temperatures ranging from 500 to 850°C. The experimental results were compared with the maximum rates calculated using the effusion formula as well as with values obtained using two different types of equations based on kinetic theory, diffusion theory, and empirical data. Equations have been derived for expressing the rate of evaporation of zinc and cadmium in both argon and helium as functions of temperature of the liquid zinc and cadmium. It was …

Evaluation Of Zinc Sulphate Electrolytes Containing Certain Impurities And Additives By Cyclic Voltammetry, D. R. Fosnacht, Thomas J. O'Keefe

Materials Science and Engineering Faculty Research & Creative Works

The polarization characteristics of acid zinc sulphate electrolytes containing various amounts of germanium and cobalt were examined by cyclic voltammetry. The effects of zinc and acid concentration, temperature, and surface preparation were also investigated. Small concentrations of impurities are shown to cause measurable changes in polarization behavior. Levels as low as 0.02 mgl-1 Ge and 0.1 mgl-1 Co can be detected using this technique. The actual mechanism of impurity behavior is more clearly delineated using this technique and evaluation of the data from these tests indicate that germanium and cobalt form local galvanic cells. The results of these short-term tests …

Discussion Of "Gas Composition, Temperature, And Pressure Measurements In A Lead Blast Furnace", Arthur E. Morris, John R. Knoepke

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

Microwave Sintering Of Batio₃ Ceramics, Kurt Duane Humphrey

Masters Theses

"Barium titanate and BaTiO₃-based multilayer capacitors were sintered in a commercial microwave oven. The oven was equipped with a 2.45 GHz continuous-wave magnetron with a maximum power output of 650 watts.

Microwave-absorbing setters made of SiC were used to offset thermal losses from the samples and allow sintering temperatures (>1325°C) to be achieved. Pure samples were pressed from commercial BaTiO₃ powder and microwave sintered to about 90% of theoretical density. Multilayer capacitors were obtained from commercial manufacturers and used in all sintering experiments. A comparison between microwave sintered material and identical samples sintered in a conventional electric furnace revealed …

Properties Of High Alumina Refractories After Exposure To Steam/H₂ Atmospheres, David W. Lang

Masters Theses

"Selected properties of a dense fired alumina, a phosphate-bonded ramming mix, and a calcium aluminate cement-bonded castable were evaluated after exposure at 260°C and 538°C to steam/H₂ atmospheres (2.58, 5.17, and 6.89) MPa. Chemical reactions in the refractories were determined by x-ray diffraction, DTA/TGA, and changes in physical properties. The modulus of rupture (MOR) of the dense alumina decreased with increasing steam pressure and degree of saturation. The calcium aluminate cement phases in the castable were most reactive in 260°C steam and formed several hydrated phases which generally resulted in a higher MOR. The MOR of the ramming mix …

Thermally Stimulated Polarization And Depolarization Current (Tspc/Tsdc) In Glass, Chi-Ming Hong

Doctoral Dissertations

"The feasibility of studying ionic motion in glass using thermally stimulated polarization (TSPC)/depolarization current (TSDC) techniques was investigated with 4Na₂O·96SiO₂ and 30PbO·70SiO₂ (mol%) glasses. The TSDC peaks in these glasses were dependent on glass composition and attributed to bulk polarization. The high temperature background TSPC is shown to be due to dc conductivity, whereas the TSPC/TSDC peaks in the 4Na₂O glass are attributed to shorter range Na⁺ motion.

The electrical conductivity of glasses determined by TSPC agrees well with that measured by conventional ac or dc techniques. The TSPC technique is a rapid and easy method of measuring the …

Calcium Migration In Dense Alumina Aged In Water And Physiological Media, Heidi H. Osterholm

Masters Theses

"The flexural strength and relative Ca concentration at the external surface were measured for a dense alumina aged in deionized water and Ringer's solution at 40⁰C for 60 weeks and at 80⁰C for 45 weeks. Changes in the Ca concentration at the external surface and flexural strength during aging were attributed to the dissolution of the calcium impurity believed to be present in a glass phase of unknown composition. Auger electron spectroscopy was used to investigate the relative concentration of the calcium impurity at the external and fracture surfaces of a dense alumina after in vivo exposure for 6, 12 …

The System Mgo‐Mgcl2‐H2o At 23°C, Ladawan Urwongse, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

Solubilities of MgO in aqueous HC1 solutions at 23°±3°C were measured and combined with analyses of neat magnesium oxychloride cements, cured in sealed containers, to construct an equilibrium phase diagram for the system MgO‐MgCl2‐H₂O. Specific gravities and acidities of solutions saturated with MgO and relative humidities of vapor phases over sealed samples were measured and combined with XRD data to define the compositions in equilibrium with two crystalline phases. Studies of relative reaction rates indicated that the 5–1–8 phase crystallizes more rapidly than the 3·1·8 phase and that cements near the 3·1·8 composition react rapidly with atmospheric CO …

Phase Relations In Magnesium Oxysulfate Cements, Ladawan Urwongse, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

Solubilities of MgO in H₂SO₄ solutions were measured and X‐ray analyses of over 100 neat cement samples were used to construct an isothermal phase diagram for the system MgO‐H₂SO₄‐H₂O at 23°±3°C. The phases MgO, Mg(OH)₂, 3Mg(OH)₂ MgSO₄·8H₂O (3·1·8), MgSO₄·7H₂O, MgSO₄·6H₂O, and MgSO₄·H₂O were stable at 23°C. The phases Mg(OH)₂· MgSO₄·5H₂O (1·1·5) and MgSO₄·4H₂O were observed but are considered to be metastable, resulting …

Autooscillations And Nonlinear Anelasticity, Manfred Wuttig, Tetsuro Suzuki

Materials Science and Engineering Faculty Research & Creative Works

In conclusion it can be stated that a novel phenomenon, a mechanical auto oscillation, has been described theoretically and shown to exist experimentally. These auto oscillations occur when a nonlinear anelastic solid is forced into large amplitude oscillations in the vicinity of a martensitic transformation. They manifest themselves as a low frequency auto modulation of the a martensitic transformation. They manifest themselves as low frequency auto modulation of the forced vibration of such a solid. © 1980.

An Experimental Study Of The Reactions Of Excited Neon Atoms In Pure Afterglow Plasmas Using Resonance Absorption Spectrometry, R. A. Sierra, J. Beverley Clark, A. J. Cunningham

Materials Science and Engineering Faculty Research & Creative Works

Resonance absorption spectrometry has been applied in a room temperature study of the reactions of excited neon atoms in pure afterglow plasmas. The pressure range 10-500 Torr was investigated. Lorentz broadened linewidths calculated using a simple classical interruption theory allowed fractional absorption signals as large as 98% to be analyzed and absolute excited-state concentrations to be determined. The first absorption studies of the decay of 1P1 excited atoms in neon afterglows are reported. Analysis of the decay profiles of the 3P2, 3P0 and 1P1 excited states allowed quenching rate coefficients for each state to be determined and the role of …

Phase Equilibria For Iron-Rich Fe-Cu-C Alloys: 1500 To 950°C, Krishna Parameswaran, Kenneth Metz, Arthur E. Morris

Materials Science and Engineering Faculty Research & Creative Works

Isothermal sections for the iron rich corner of the Fe-Cu-C system have been constructed at 1500, 1450, 1200, 1172, 1150, 1000, and 950°C. A ternary invariant point exists at 1172°C where an iron rich liquid, a copper rich liquid, austenite, and graphite coexist. The iron rich liquid contains 3.7 wt pct Cu and 4.0 wt pct C. The austenite contains 7.3 pct Cu and 1.6 pct C. The copper rich liquid contains 2.4 pct Fe, and apparently very little carbon. The diagrams are used to explain the phenomena of "inverse segregation" that occurs during the solidification of iron rich Fe-Cu-C …

Boehmite-Bonded High-Alumina Refractories, Gerhard H. Schiroky

Masters Theses

"High-alumina refractories (99+ % Al₂O₃) were produced by pressing a mixture of 70% tabular alumina and 30% reactive alumina and autoclaving in saturated steam at 1.4 MPa (200 psia)/194 °C to 3.4 MPa (500 psia)/242 °C for 12 to 96 h. Autoclaving converted the reactive alumina to boehmite which acted as the bond phase. At room temperature the MOR ranged up to 37 MPa depending upon boehmite content. The hot-MOR decreased steadily with increasing temperature, but was still 8 MPa at 1400 °C which exceeds that of comparable cement-bonded or conventionally fired high-alumina refractories. The estimated autoclaving costs are lower …

Processing Of Copper Refinery Anode Slimes, Shrirang Anant Kulkarni

Masters Theses

"A study of commercial copper refinery anode slimes has been conducted to evaluate the separation of valuable metals contained in the slimes. The slimes contain substantial quantities of Ag, Sn, Au, Pb, and Cu. The values were present principally as AgCl, SnO₂, Au, PbSO₄, Cu and CuSO₄.

A Roast-Leach-Roast-Leach (RLRL) technique solubilized up to 91 pct of the Ag and 99 pct of the Cu from raw slimes.

The Pb-Sn separation was investigated using the following hydrometallurgical techniques: 1) DETA (diethylene triamine) leaching; 2) NaOH leaching; 3) (NH₄)₂CO₃ leaching; …

Pelletizing Of A Lead Sinter Machine Feed, Hung-Yang Tsai

Masters Theses

"A typical lead sinter machine feed can be pelletized in a drum pelletizer using tap water as a binding liquid. The green pellets produced have return sinter as cores, and an outer layer of new material and fluxes. The moisture content of the pellets produced is about 5%. The pelletizing procedure developed used raw materials from the Amax Lead Smelter, with only a minor amount of feed preparation. The importance of proper moisture control, use of binders, method of adding moisture, speed of pelletizing drum, etc. were investigated. The stability of pellets under extreme storage conditions was also determined"--page ii.

A Metallurgical Evaluation Of The Mi Vida Prospect: A Mixed Copper Sulfide-Carbonate Ore Body, Sells, Pima County, Arizona, Kevin Michael Kenney

Masters Theses

"A copper-prospect in south-central Arizona has been evaluated on a metallurgical basis. Primary chalcocite and secondary covellite, plus the copper oxides malachite and brochantite, constitute the economic mineralization. The deposit outcrops as a steeply dipping (70°SW), intensely brecciated, copper-bearing quartz vein with discontinuous lenticular ore shoots.

Acid leaching techniques alone and in conjunction with froth flotation utilizing four copper oxide specific collectors were used to evaluate the amenability of this ore to processing. Direct acid leaching was examined and found to be ineffective. Removal of the chalcocite by froth flotation with xanthate was easy and gave better results to subsequent …

Molybdenum Stability In Coal Slags At 1400⁰C: Corrosion Properties For Mhd Electrode Applications., Kenton Brian Wright

Masters Theses

"Molten coal slag corrosion studies conducted on molybdenum at 1400°C used static and stirred slag experiments and electrical current experiments to parallel electrode conditions of slagging duct MHD generators. Crucibles containing molybdenum and slag were exposed to combustion-type gases in a tube furnace. Carbon monoxide-carbon dioxide gas mixtures controlled oxygen partial pressures at selected values between 10^-11 and 10^-3 atm. Metallograph and microprobe examination of polished sample sections defined corrosion characteristics.

At 1400°C, molybdenum metal is stable below 10^-9 atm oxygen pressure. Molybdenum dioxide is stable at higher pressure, but volatile molybdenum trioxides prevent formation of stable …

Thermally Stimulated Polarization Current Technique For Measuring The Electrical Conductivity Of Vitreous Solids, Chi-Ming Hong, D. E. Day

Materials Science and Engineering Faculty Research & Creative Works

The electrical conductivity of glasses determined by TSPC agrees well with that measured by conventional ac or dc techniques. The TSPC technique is a rapid and easy method of measuring the dc conductivity over the range 10−15-10−7 (Ω cm)−1 and is especially suited for conductivities <10−12 (Ω cm)−1. Polarization at the electrodes is easily detected and avoided.

Nonlinear Anelasticity And The Martensitic Transformation, Manfred Wuttig, Tetsuro Suzuki

Materials Science and Engineering Faculty Research & Creative Works

Zener's model of a standard linear solid is extended to include nonlinearities characteristic of metals and alloys in the vicinity of a martensitic transformation. The equation of motion of a nonlinear anelastic solid is derived and solved using van der Pol's method. The characteristics of the solutions indicate that auto-oscillations of finite amplitude can be excited externally. It is proposed that the streaming oscillations represent the beat between the external excitation and the auto-oscillation. © 1979.