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Materials Science and Engineering Faculty Research & Creative Works

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Articles 961 - 990 of 1011

Full-Text Articles in Materials Science and Engineering

Knudsen Effusion Study Of The Vaporization Of Cdo(S), R. Tom Coyle, Gordon Lewis Jan 1974

Knudsen Effusion Study Of The Vaporization Of Cdo(S), R. Tom Coyle, Gordon Lewis

Materials Science and Engineering Faculty Research & Creative Works

Knudsen effusion studies were conducted on CdO(s) in fused‐SiO2 Knudsen cells from 889 to 1110 K. The orifice size was varied; the largest cell orifice yielded a calculated pressure significantly lower than could be accounted for by experimental error. Average‐slope‐ and average‐free‐energy‐function‐based values of ΔHc298 were 86.9 ± 1.1 and 88.8 ± 0.5 kcal/mol, respectively. The data from the present work were combined with those of previous investigators using a method discussed by McCreary and Thorn; a ΔHc298 of 88.2 ± 0.2 kcal/mol was obtained. Using this combined value for ΔHc298 and ΔSc298= 51.40 ± 0.1 eu (obtained from the …

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Magnetostrictive Aftereffect In A Dilute 50fe-50ni-C Alloy, Raj Master, Manfred Wuttig Jan 1974

Magnetostrictive Aftereffect In A Dilute 50fe-50ni-C Alloy, Raj Master, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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X-Ray Powder Data And Unit Cell Parameters Of Mgcl2.6h2o, Charles A. Sorrell, Roy R. Ramey Jan 1974

X-Ray Powder Data And Unit Cell Parameters Of Mgcl2.6h2o, Charles A. Sorrell, Roy R. Ramey

Materials Science and Engineering Faculty Research & Creative Works

Detailed X-ray powder data for MgCl2·6H2O were obtained by diffractometry by use of CuKα radiation at 22°C. The data were indexed on a bimolecular monoclinic unit cell, space group C2/m, with a = 9.858 ± 0.001 Å; b = 7.107 ± 0.001 Å; c = 6.069 ± 0.001 Å; ß = 93° 47′ ± 10′. Calculated density was 1.591 g/cm3, compared with a measured density of 1.593 ± 0.003 g/cm3. © 1974, American Chemical Society. All rights reserved.

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Influence Of Oxygen Activity On The Sintering Of Mgcr2o4, Harlan U. Anderson Jan 1974

Influence Of Oxygen Activity On The Sintering Of Mgcr2o4, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

The sintering behavior of MgCr2O4 powder compacts was investigated as a function of temperature, time, and oxygen activity. The results show that MgCr2O4 cannot be densified to >70% of theoretical density at temperatures up to 1700°C if the oxygen activity exceeds 10−6 atm. The oxygen activity must be decreased to <10−10 atm before densities exceeding 90% of theoretical can be achieved. Weight loss and X‐ray data indicated that maximum density occurred at an oxygen activity just above that where MgCr2O4 becomes unstable. Copyright © 1974, Wiley Blackwell. All rights reserved

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Formation And Densification Of Cadmium Manganese Ferrite, B. W. Jong, P. D. Ownby Jan 1973

Formation And Densification Of Cadmium Manganese Ferrite, B. W. Jong, P. D. Ownby

Materials Science and Engineering Faculty Research & Creative Works

Formation of Ni-ferrite, Mn-ferrite, NiZn-ferrite, Zn-ferrite and Mg-ferrite have been investigated using X-ray diffraction analysis. Jander's diffusion equation described the data from these investigations over a portion of the temperature ranges studied. However, the reaction mechanisms and sequences involved in the formation of mixed ferrites have not been well defined in the literature. The purposes of this investigation were: ( 1) To further the understanding of the formation of CdMnferrite by studying first the kinetics of the formation of Cd-ferrite and Cd-manganite, which provides a basis for understanding the details of the mixed CdMn-ferrite reaction and to obtain the optimum …

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Oxidation Of Tetragonal Pbo In Air, Charles A. Sorrell Jan 1973

Oxidation Of Tetragonal Pbo In Air, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

Isothermal oxidation of tetragonal PbO in air produced multiphase assemblages with apparent equilibrium compositions which varied linearly with temperature from PbO1.548 at 286°C to PbO1.333 at 351°C. Oxidation at each temperature was relatively rapid to PbO1.40 and very slow from PbO1.40 to apparent equilibrium values. Pseudocubic PbO1+x, with compositions between PbO1.41 and PbO1.57, was indexed on a cubic unit cell at the lower O/Pb ratios and on a tetragonal unit cell at the higher ratios. Linear changes in lattice parameters and deviation from cubic symmetry accompanied reversible oxidation and reduction of the phase. Pseudocubic PbO1+x was reduced irreversibly to Pb3O4 …

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Oxidation State Control Of Volatile Species In Sintering, P. D. Ownby Jan 1973

Oxidation State Control Of Volatile Species In Sintering, P. D. Ownby

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Polynary Silicon Arsenic Chalcogenide Glasses With High Softening Temperatures, H. E. Anthonis, N. J. Kreidl, W. H. Ratzenboeck Jan 1973

Polynary Silicon Arsenic Chalcogenide Glasses With High Softening Temperatures, H. E. Anthonis, N. J. Kreidl, W. H. Ratzenboeck

Materials Science and Engineering Faculty Research & Creative Works

The introduction of Ag in SiAsTe glasses permits the incorporation of Se, otherwise volatile and/or degradable as a constituent in Si-containing chalcogenide glasses. SiAsAgTeSe glasses exhibit much higher softening ranges and glass transition temperatures than encountered in known chalgogenide systems. A glass Si35As15Ag10Te20Se20 had the viscosity log ν = 13 at about 500°C, as compared to 370°C for the base glass Si35As25Te40, the viscosity of log ν = 9.8 at about 560°C, as compared to 442°C for the base glass. Phase separation occurs in the system SiAsAgTeSe and becomes manifest in two glass transitions indicated by changes in the slopes …

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Low Temperature Lattice Parameters And Expansion Coefficients Of Ai2au And Lif Gruneisen Constants Of Lif, Martin E. Straumanis, Jayant S. Shah Jan 1972

Low Temperature Lattice Parameters And Expansion Coefficients Of Ai2au And Lif Gruneisen Constants Of Lif, Martin E. Straumanis, Jayant S. Shah

Materials Science and Engineering Faculty Research & Creative Works

There is no difference in the thermal expansion behavior of an intermetallic compound (Al2Au) and of an ionic (LiF), except in the magnitude of the expansion coefficients, which for both compounds upon cooling below 40°K approach zero. The lattice parameters of the two compounds mentioned decrease uniformly and without anomalies with lowering the temperature, approaching a constant value below 40°K. The a–T relationship between 40 and 180° is given in form of equations. A pump working on the Joule‐Thomson principle was used for cooling. The GRÜNEISEN parameter, γ, of LiF between 40 and 180°K is a constant, contrary to theoretical …

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Irradiation Enhanced Decomposition Of A Nickel-Carbon Solid Solution, B. L. Shriver, Manfred Wuttig Jan 1972

Irradiation Enhanced Decomposition Of A Nickel-Carbon Solid Solution, B. L. Shriver, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

This investigation was performed to determine the effects of room temperature neutron irradiation on the distribution of carbon in a nickel-0.3 wt.% carbon alloy. The experiment consisted of comparing the amount of carbon in solid solution and the internal stresses of both unirradiated and irradiated (1013 fn-cm-2 < ΦF < 1018 fn-cm-2) samples following isochronal anneals between 100 and 1200°C by using the magnetic Dis accommodation technique. The results indicate that the amount of carbon remaining in solid solution decreases with increasing neutron dose. At temperatures below 200°C this is due to the trapping of carbon by mobile irradiation-produced defects. Between 200 and 600°C the formation of metastable carbides is enhanced by the presence of irradiation-produced defects. No differences are observed in irradiated and unirradiated samples above 600°C. © 1972.

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Polynary Telluride Glasses Containing Silver, H. E. Anthonis, N. J. Kreidl Jan 1972

Polynary Telluride Glasses Containing Silver, H. E. Anthonis, N. J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Thermal Expansion Behavior Of Silicon At Low Temperatures, Jayant S. Shah, Martin E. Straumanis Jan 1972

Thermal Expansion Behavior Of Silicon At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

Lattice parameters, thermal expansion coefficients and Grüneisen parameters of silicon are determined by an X-Ray diffraction method in the temperature range of 180-40 K without the use of liquid gases. Thermal expansion of silicon becomes negative below 120 K which is discussed in terms of its lattice vibrations and crystal structure. © 1972.

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Nonstoichiometry In Batio3, G. J. Conger, Harlan U. Anderson Jan 1972

Nonstoichiometry In Batio3, G. J. Conger, Harlan U. Anderson

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Dissolution Potentials And Activation Energies Of Insb Single Crystals, Martin E. Straumanis, Lih Da Hu Jan 1972

Dissolution Potentials And Activation Energies Of Insb Single Crystals, Martin E. Straumanis, Lih Da Hu

Materials Science and Engineering Faculty Research & Creative Works

The rest (or corrosion) and dissolution potentials of InSb single crystals in HC1 were determined. There is no potential difference (within error limits) between the inverse {111} faces in pure HC1. A difference of up to 44 mV and more develops as soon as the InSb electrode is anodically dissolved. The potential becomes less noble in the sequence In{111}, {100}, {110}, Sb{111}. The Tafel relationship is observed over three decades of current density. With additions of FeCl3, FeCl2, K3Fe(CN)6, K4Fe(CN)6, H2C4H4O6 to 2N HC1, the anodic potentials of both inverse {111} faces are shifted to more active values; the e'H …

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Comment On The Nature Of The Disaccommodation In Hcp Co-C Alloys, J. Keiser, Manfred Wuttig Jan 1972

Comment On The Nature Of The Disaccommodation In Hcp Co-C Alloys, J. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Activation Volumes Of Carbon Diffusion In Fcc Iron-Nickel Alloys, J. Keiser, Manfred Wuttig Jan 1972

Activation Volumes Of Carbon Diffusion In Fcc Iron-Nickel Alloys, J. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The Dis accommodation technique was used to determine the activation volume of carbon diffusion, ΔV, in six fcc iron-nickel alloys. Measurements were made at temperatures ranging from 68 to 90 °C and pressures up to 6 kbar on samples having a nickel content between 31 and 63 at.%. A maximum activation volume of 3.9 cm3/mole was found at 34 at.% nickel. The compositional dependence of ΔV is satisfactorily reproduced by a magnetic-energy continuum model in which it is assumed that the activation free energy of diffusion is essentially ferromagnetic in origin. © 1972 The American Physical Society.

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Pbo Transformation Induced By Water, Charles A. Sorrell Jan 1972

Pbo Transformation Induced By Water, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis Dec 1971

Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

Lattice parameters, thermal expansion coefficients, and Grüneisen parameters of tungsten are determined by an x-ray method in the temperature range of 180-40 K without the use of liquid gases. Lattice parameters are expressed as a function of temperature. Thermal-expansion coefficients decrease with temperature and show no anomaly in contrast to a hypothesis proposed by Featherston and Neighbours. Grüneisen parameters γ are decreasing with temperature in accordance with the theoretical predictions. © 1971 The American Institute of Physics.

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Liquid Viscosity Measurement Using A Buret: An Instructional Technique, Charles A. Sorrell Jan 1971

Liquid Viscosity Measurement Using A Buret: An Instructional Technique, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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A Magnetic Aftereffect In Dilute H.C.P. Co-C Alloys, J. R. Keiser, Manfred Wuttig Jan 1971

A Magnetic Aftereffect In Dilute H.C.P. Co-C Alloys, J. R. Keiser, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

A magnetic Dis accommodation in dilute h.c.p. Co-C alloys has been observed around 90°C. The thermally activated process giving rise to the Dis accommodation is characterized by an activation energy of 26 kcal mole-1 and an attack frequency on the order of 10+13 sec-1. An application of the selection rules shows that the Dis accommodation cannot be caused by the redistribution of tetrahedral or octahedral interstitials or any nearest neighbor interstitial pairs as long as the defects interact linearly with the internal magnetic field. © 1971.

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On The Activation Entropy Of Interstitial Diffusion In B.C.C. Iron, Manfred Wuttig Jan 1971

On The Activation Entropy Of Interstitial Diffusion In B.C.C. Iron, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Mixed‐Cation Effect In Silver Borate Glasses, E. N. Boulos, N. J. Kreidl Jan 1971

Mixed‐Cation Effect In Silver Borate Glasses, E. N. Boulos, N. J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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The Anodic Dissolution Reaction Of Insb: Etch Patterns, Electron Number, Anodic Disintegration, And Film Formation, Martin E. Straumanis, Lih Da Hu Jan 1971

The Anodic Dissolution Reaction Of Insb: Etch Patterns, Electron Number, Anodic Disintegration, And Film Formation, Martin E. Straumanis, Lih Da Hu

Materials Science and Engineering Faculty Research & Creative Works

The etching behavior of the inverse {111} planes of undoped, semiconducting, n-type, InSb single crystals was explored. Depending upon the etchant, including anodic dissolution, various etch patterns were obtained on the inverse planes. In general, the etch pits on the In{111} plane were round, and the face was shiny, whereas the face of the inverse plane was dark and rough. The rates of dissolution in the electrolytes used were very low, especially in absence of oxidizers. The components dissolve as In3+ and Sb3 +. At current densities above 40 or 60 mA cm-2 (on Sb{111} or In{111}), growth of a …

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Stored Energy Of Room Temperature Deformed Copper, G. J. Filatovs, Hollis P. Leighly Jan 1971

Stored Energy Of Room Temperature Deformed Copper, G. J. Filatovs, Hollis P. Leighly

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Thermal Expansion Of Pb3o4, Charles A. Sorrell Jan 1971

Thermal Expansion Of Pb3o4, Charles A. Sorrell

Materials Science and Engineering Faculty Research & Creative Works

Thermal expansion of Pb3O4 was investigated by high‐temperature X‐ray diffraction. The coefficient in the a0 direction is 14.6x10−6/°C. Expansion in the c0 direction is 32% greater, with a coefficient of 19.3x10−6/°C. Coefficients of expansion are linear from 25° to 490°C and are comparable with those of tetragonal and orthorhombic PbO. Copyright © 1971, Wiley Blackwell. All rights reserved

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Structure And Properties Of Silver Borate Glasses, E. N. Boulos, N. J. Kreidl Jan 1971

Structure And Properties Of Silver Borate Glasses, E. N. Boulos, N. J. Kreidl

Materials Science and Engineering Faculty Research & Creative Works

Clear glasses form in the system Ag2O‐B2O3 up to about 35 mol% (65 wt%) Ag2O. Infrared absorption, thermal expansion, and density data indicated an analogy to the Na2O‐B2O3 system. Pentaborate‐triborate group pairs appear to be formed on addition of Ag2O to B2O3 up to 20 mol% Ag2O and diborate groups from 20 to 33 mol% Ag2O. This interpretation is supported by the comparison of the infrared absorption spectra of quenched and crystallized glasses. One crystallization product, Ag2O‐4B2O3, was …

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Activation Volumes Of Interstitial Diffusion In Ferromagnetic Metals And Alloys, Manfred Wuttig, J. Keiser Jan 1971

Activation Volumes Of Interstitial Diffusion In Ferromagnetic Metals And Alloys, Manfred Wuttig, J. Keiser

Materials Science and Engineering Faculty Research & Creative Works

The Dis accommodation technique was used to determine the activation volumes of carbon diffusion ΔV of a Fe-1.4 wt% Si alloy, of hcp cobalt, and of nickel at the temperatures of -21, 75, and 110°C, respectively. The obtained values of ΔV are +0.3 ± 0.3 and -0.6 ± 0.9 cm3 mole-1 for the two relaxations observed in hcp cobalt, and 1.2 ± 0.1 cm3 mole-1 for nickel. These results are discussed in terms of a continuum model that interprets the activation energy of diffusion as a sum of the strain and exchange energies. It is found that in ferromagnetic solids …

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Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis Dec 1970

Thermal Expansion Of Tungsten At Low Temperatures, Jayant S. Shah, Martin E. Straumanis

Materials Science and Engineering Faculty Research & Creative Works

No abstract provided.

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Diffusion In Wide Grain Boundaries, J. Mimkes, Manfred Wuttig Dec 1970

Diffusion In Wide Grain Boundaries, J. Mimkes, Manfred Wuttig

Materials Science and Engineering Faculty Research & Creative Works

The rigorous solution of the grain-boundary diffusion problem has been approximated by a series expansion method. The calculations show that higher-order terms may be neglected in the bulk adjacent to the grain boundary. Thus, in this region Whipple's and Suzuoka's solutions represent a close approximation to the problem. Inside the grain boundary, however, higher-order approximations have to be taken into account. These approximations gain importance in the case of wide grain boundaries. The solutions obtained for an instantaneous source have been fitted to available grain-boundary diffusion data of Ni2+ in MgO at 1200°C. Numerical calculations give for the bulk diffusion …

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Phase Equilibria And Thermodynamic Studies In The System Cao-Feo-Fe2o3-Sio2, M. Timucin, Arthur E. Morris Nov 1970

Phase Equilibria And Thermodynamic Studies In The System Cao-Feo-Fe2o3-Sio2, M. Timucin, Arthur E. Morris

Materials Science and Engineering Faculty Research & Creative Works

Phase equilibria and thermodynamic properties of the system CaO-FeO-Fe2O3-SiO2 were studied at 1450° and 1550°C, over a range of pO2 from 1 to about 10-11 atm. Isothermal phase diagrams and activity-composition diagrams were constructed for 0, 5, 10, 20, and 30 wt pct SiO2 sections. The data are applicable to further understanding the behavior of simple BOF steelmaking slags. © 1970 The Minerals, Metals & Materials Society - ASM International - The Materials Information Society.

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