bluuebunny/crossref_metadata_2025 huggingface dataset:
Breaking Stress of Glass Determined from Dimensions of Fracture Mirrors
Authors: SHAND E. B.
Published: June 2006

Relations previously have been shown between the size of the fracture mirror and the nominal breaking stress. In the present paper, this relation is derived analytically involving one unknown quantity which must be determined experimentally. This quantity is δm√ρ where δm is the intrinsic strength of the glass and the effective radius of the crack tip. Tests on glass rods indicated that the breaking stress could be determined from the radius of the fracture mirror. For 80% of the specimens the values obtained were within 8% of those obtained from the test loads.
Attack of Glass by Chelating Agents
Authors: ERNSBERGER F. M
Published: June 2006

The chemical attack of a soda‐lime glass by the combined action of ethylene diamine tetraacetic acid and ortho‐dihydroxy benzene (catechol) in dilute aqueous solution is reported u a function of pH. A pronounced maximum occurs in the rate of attack at a pH value determined by the anionic species present. The effects are ascribed to the chelation of the protective cations A13+, Ca2+, and Mg2+ by ethylene diamine tetraacetic acid and to the chelation of Si4+ by catechol.
High‐Temperature Mechanical Properties of Ceramic Materials: II, Beta‐Eucryptite
Authors: BUSH E. A. , HUMMEL F. A.
Published: June 2006

High stresses arise in sintered β‐eucryptite (Li2O. Al2O2‐2SiO2) during cooling from the firing temperature because of its extreme anisotropy of thermal expansion. These stresses cause extensive fracturing of the crystals, resulting in abnormally low mechanical property values at room temperature. During reheating, many fractures recombine, causing increase in strength and in elastic modulus with increasing temperature. Beta‐eucryptite creeps under load at room temperature because of additional fracturing and the propagation of fractures. Equations are presented for calculating internal stresses in sintered single‐phase aggregates of anisotropic crystals.
Oxygen Ion Mobility in Cubic Zr0.85Ca0.15O1.85
Authors: KINGERY W. D. , PAPPIS J. , DOTY M. E. , HILL D. C.
Published: June 2006

Oxygen ion mobility in the cubic fluorite‐structure phase having the composition Zr0.85 Ca0.15 O1.85 has been directly determined by exchange measurements employing the stable isotope O18 and mass spectrometer analysis. Measurements of electrical conductivity have been carried out as a function of both temperature and oxygen pressure. Results indicate that the conductivity is wholly ionic with a transfer number near unity for the oxygen ion.
Dielectric Losses of Some Simple Ternary Silicate Glasses
Authors: RINEHART D. W. , BONINO J. J.
Published: June 2006

The effect on alkali ion mobility of compositional changes in simple glasses was investigated by observing the dielectric loss behavior in a number of ternary glass systems, formed by adding increasing amounts of various third components to potassia‐silica and soda‐silica base glasses. Oxides of barium, strontium, calcium, cadmium, lead, magnesium, zinc, aluminum, boron, tin, zirconium, titanium, and silicon were introduced. Tan δ values were determined at room temperature and at a frequency of 1 kc. per second. Na+ ion mobility was found to be profoundly influenced by the type and amount of third component present. RO oxides decreased tan δ by amounts which appear to bear some relation to the size of the cation introduced. Tan δ curves for the MgO and ZnO series were unique in that each was characterized by a pronounced minimum and maximum. Curves for SnO2, Al2O3, and ZrO2 additions passed through a minimum and in the latter two cases rose to tan δ values greater than that of the base glass itself. Curves for the series containing B2O3 and TiO2 continued to lower values throughout the range of compositions studied. The characteristic shapes of the loss curves are discussed with reference to the roles assumed by the introduced cations.
Exploration of Lithia Glassforming Systems: I, Li2O‐CaO‐Al2O3‐SiO2, at Different Levels from 0 to 30 Weight % CaO
Authors: RAUCH H. W. , COMMONS C. H. , BLAU H. H.
Published: June 2006

Areas of glass formation were determined in the system Li2O‐CaO‐Al2O3‐SiO2 at different levels from 0 to 30 weight % CaO. Thermal, chemical, optical, and electrical properties also were determined. Some of the glasses, especially those at the higher CaO levels, may find commercial application.
Thermal Fracture Resistance of Ceramic Coatings Applied to Metal: I, Elastic Deformation
Authors: LAUCHNER J. H. , BENNETT D. G.
Published: June 2006

A study was made of the resistance to thermal fracture of four ceramic coatings of the cobalt‐bearing ground‐coat type applied to enameling‐grade iron specimens. The study was made of coated‐metal systems in the unsteady state, symmetrically cooled, and in the absence of viscous or plastic flow. Determinations were made of the elastic characteristics of the coating‐metal composites, the effective coefficient of linear expansion, the temperature at which the coating and base metal were at dimensional equilibrium, and the temperature differential sufficient to induce coating fracture when water quenched. Coating‐metal thickness ratios were correlated with the maximum specimen temperature withstood in water quenching without coating fracture. Studies indicated that ceramic coatings, after receiving a given thermal treatment, fracture when subjected to a thermal shock by a critical temperature differential. When no residual coating stress is present, thermal shock resistance is inversely related to the thermal expansion characteristics of the coating. The critical stress at which coating fracture occurs may be expressed as the sum of thermal and residual stresses developed in annealed systems in which viscous or plastic flow does not occur. Residual compressive stress in a coating is a major factor in improved thermal shock resistance. Increased thermal shock resistance is gained by decreased coating thickness.
Thermal Expansion of MgFe2O4, FeO, and MgO·2FeO
Authors: CARTER R. E.
Published: June 2006

The thermal expansion of magnesium ferrite, wüstite, and magnesio‐wüstite has been measured up to 1000°C. Good agreement has been found with published data obtained at lower temperatures, but the reported extrapolations have been shown to be low. The thermal expansion of MgFe2O4 has been interpreted to support Gilleo's hypothesis that the super‐exchange energy for Fe3+‐O2‐‐Fe3+ linkages is independent of the Fe3+‐O2‐ distance. This conclusion is supported by the fact that the energy per linkage is the same as that for Fe3+‐O2‐Fe3+ linkages in a variety of crystal structures.
Effects of Viscosity and Stress Level on Rates of Stress Release in Soda‐Lime, Potash‐Barium, and Borosilicate Glasses
Authors: McGRAW D. A. , BABCOCK C. L.
Published: June 2006

Previous work has suggested that two concurrent mechanisms act to relieve stresses in soda‐lime commercial glasses in the viscosity range log 12 to log 14.5. The data were found to be best represented by a relation which indicated that the release of stress is the result of at least two distinct, but not necessarily independent, rate processes. The present paper shows stress release and viscosity data on two other types of glasses, namely, a potash‐barium glass and a borosilicate. The data show that all three types of glass can be represented by similar equations and that the release of stress in glasses is related to both equilibrium temperature viscosities and delayed elasticity within the annealing zone.
Studies in Lithium Oxide Systems: VII, Li2O–B2O2–SiO2
Authors: SASTRY B. S. R. , HUMMEL F. A.
Published: June 2006

Phase relations in the system Li2O–B2O3–SiO2 were studied by quenching and solid‐state reactions. No ternary compounds were detected in the portion of the system containing less than 53% Li2O. Compatibility triangles were formed from the binary borate and silicate compounds. Liquidus data obtained by quenching are reported for four joins, Li2O·2SiO2–Li2O·2B2O3, Li2O·SiO2‐Li2O·2B2O3, Li2O·SiO2‐Li2O·B2O3, and Li2O·2B2O3‐SiO2. The last join cuts across the two‐liquid region and is not a true binary system. Some probable ternary invariant points were located in the portion of the system which was quenchable to glass and adjacent to the two‐liquid region. Further data on the previously reported immiscible liquid formation are given and the significance is discussed. Data on the thermal expansion behavior of certain glasses are presented.
An Optical Study of Talc‐Tremolite Relations
Authors: WRIGHT HAROLD D.
Published: June 2006

An optical study of talc‐tremolite from Fullerville, St. Lawrence County, New York, confirmed the crystallographic orientation determined by Stemple and Brindley. Both minerals exhibit normal optic properties. The optic orientation of talc given in standard references appears to be in error.
Volatility of Lead Silicate and Lead Borate Binary Melts
Authors: HIRAYAMA CHIKARA
Published: June 2006

The volatility of binary lead silicate and lead borate melts has been determined at reduced pressures. These systems contain more than 71%, lead oxide. At comparable temperatures, the volatility of the binary lead silicate melt is higher than that of the lead borate of corresponding PbO to boron ratio. The volatilization of PbO is diffusion controlled. The approximate vapor pressure of PbO at 900°C. is 0.2 mm. Hg.
Oxidation Studies of Urania‐Thoria Solid Solutions
Authors: LYNCH E. D. , HANDWERK J. H. , HOENIG C. L.
Published: June 2006

Nonstoichiometric solid solutions in the system UO2‐ThO2 were formed by sintering U3O‐ThO3 and codigested nitrate mixtures in air. The oxygen content of the solid solutions was determined by a weight‐loss method. The changes occurring in oxygen content during solid solution formation and densification were determined for a 70.4 mole % UO2‐29.6 mole % Tho2 composition formed by sintering U3O3‐ThO2 in air. The first evidence of solid solution occurred at 1000° C. and solution was complete above 1250°C. Thermal cycling of solid solutions in air showed a minimum oxygen‐uranium ratio of 2.34 for the compositions studied. The minimum oxygen‐uranium ratio obtained during thermal cycling decreased with increasing Tho2 content.
Phase Equilibria in the System Iron Oxide—Cr2O3– SiO2 in Air
Authors: MUAN ARNULF , SÖMIYA SHIGEYUKI
Published: June 2006

Phase equilibrium data, obtained by the quenching technique, are presented for the liquidus temperature region of the system iron oxide‐Cr2O3‐SiO2 in air, which represents an O2 isobaric section (po2= 0.21 atm.) through the quaternary system Fe‐Cr‐Si‐O at a total pressure of 1 atm. The diagram is dominated by a large area of coexistence of two immiscible liquids, and high liquids temperatures prevail throughout most of the system. Possible applications to refractory problems are indicated.
The System Magnesia‐Silica‐Water Below 300°C.: I, Low‐Temperature Phases from 100° to 300°C. and Their Properties
Authors: YANG JULIE CHI‐SUN
Published: June 2006

Reactions in the ternary system MgO‐SiO2‐H2O were studied over the temperature range 100° to 300° C. and were found to produce only two phases. Under conditions of 100° to 200° C. and atmospheric pressure up to 20,000 lb. per sq. in., and regardless of the initial MgO/SiO2 ratio, the predominant magnesium silicate product was found to have a MgO/SiO2 ratio of 1.5. In the range 200° to 300°C. at 210 to 20,000 lb. per sq. in. two stable phases, 3MgO.2SiO2.2H2O (I) and 3MgO.4SiO2.H2O (II), were observed. In this case the phase that was favored was determined by the molar ratio of MgO/SiO2 of the reaction mixture at the start of the run. The physical and chemical properties of phases (I) and (II) resembled those of the natural minerals serpentine and talc respectively. Two different morphologies were observed in electron micrographs of phase (I). From 100° to 160°C. it occurred as crumpled foils, and at 170°C. fibrous crystallites, which resembled the natural asbestos mineral chrysotile, appeared at the expense of some of the foils.
High‐Temperature Reactions of Clay Mineral Mixtures and Their Ceramic Properties: I, Kaolinite‐Mica‐Quartz Mixtures with 25 Weight % Quartz
Authors: BRINDLEY G. W. , UDAGAWA S.
Published: June 2006

The mineralogy and ceramic properties (linear shrinkage and porosity) of fired compacts of quartz, kaolinite, and mica containing 25% of quartz and variable proportions of kaolinite and mica were studied systematically in relation to composition and firing temperature. A procedure for the quantitative determination of components by X‐ray diffraction measurements is outlined and applied to the determination of quartz and mullite in the fired samples. For a mixture containing 25%, quartz, 75% kaolinite, the amount of mullite developed at 1300°C. is 41% and this contains 85% of the total Alsoa available. In micarich mixtures, mullite develops at lower temperatures and in smaller proportions. The shrinkage and porosity vary systematically with the percentage of mica in the samples and with firing temperature. The formation of cristobalite depends on the kaolinite content and is not related to the quartz content. Mullite and cristobalite develop at about 1100°C. from the transitory Si‐Al spinel‐type phase derived from kaolinite.
Indentation Strength of Glass
Authors: ARGON A. S. , HORI Y. , OROWAN E.
Published: June 2006

The tensile strength of plate and sheet glasses was investigated by means of indentation experiments with small spherical indenters. In agreement with earlier experiments by Powell and Preston, tensile strengths were observed about 10 to 100 times higher than those found in tensile or bending tests, the highest values being about one‐half the greatest strength of thin fibers or freshly drawn rods. It did not seem that any further reduction of the diameter of the indenting sphere below 1 mm. would lead to a significant increase of the highest strength values. The highest values of the indentation strength of freshly cleaved surfaces were not above those of ordinary surfaces, although the average was considerably higher. This indicates that, unless the use of the Hertz stress distribution involves a significant inaccuracy, the upper limit of about 300,000 lb. per sq. in. of the tensile stress may represent the order of magnitude of the tensile strength of bulk glass in the absence of surface defects. This value is within a factor of two to five of the probable molecular tensile cohesion of a glass of maximum homogeneity. Fracture stress histograms and maximum endured stress histograms are given for a variety of flat glasses.
Solid Solution Dielectrics Based on Sodium Niobate
Authors: GLAISTER R. M.
Published: June 2006

The dielectric properties of some twenty solid solution systems based on sodium niobate are described, the additives being classified into ABO3, AB2O6, and A2B2O7 types. Properties of the systems NaNbO3‐BaTiO3, NaNbO3–SrTiO3, and NaNbO3‐Sr2Ta2O7 are described in some detail. A composition in the last system has permittivity and loss tangent values at 1600 cycles per second of 2600 and 0.003, respectively, at 20°C. and 1600 and 0.025, respectively, at 200OC. The system NaNbO3‐SrTiO3 undergoes a phase transition from orthorhombic to cubic symmetry at 15 to 20 mole % SrTiO3 accompanied by a change from NaNbO3‐type behavior to para‐electric behavior. Results on some mixed‐crystal systems are also reported.
Effect of Water Content on Corrosion of Borosilicate Glass
Authors: PRIEST D. K. , LEVY A. S.
Published: June 2006

The effect of water content on the corrosion resistance of a proprietary borosilicate glass is discussed. Several glass smelting methods were employed to produce an alkali borosilicate glass with various amounts of water within the body of the glass. Infrared studies in the region 2.7 to 3.0 P showed that a decrease in the O–H groups in the glass resulted in a decrease in the amount of absorption in this region. The corrosion resistance of these glasses was measured in the vapor phase over boiling 20% hydrochloric acid. A correlation between water content and corrosion resistance is shown.
Contribution to the Study of Moisture Expansion in Ceramic Materials
Authors: DEMEDIUK THAISA , COLE W. F.
Published: June 2006

Measurements were made of the expansions produced by autoclaving coprecipitated and mixed gels of silica and alumina fired over the temperature range 850° to 1200°C. The effect of adding soda to gels of kaolinite composition was investigated and the compositions of the phases were determined. The results show that amorphous silica has a limited influence and must be modified by alumina or by soda and alumina to produce expansions comparable with those of ceramic bodies. The active material is an amorphous alkali aluminosilicate, to be distinguished from permutites and glass. Formation of glass and crystalline compounds reduces moisture expansion. At low firing temperatures (below 950° C.) the hydration of γyAl2O3 to boehmite produces high moisture expansions, but γ‐Al2O3 modified by silica (silicon spinel) has only a limited influence. Some observations are made on the nature of cristobalite developed during the firing of pure amorphous silica and amorphous silica into which additives were introduced.
Mechanical Properties of Magnesia Single Crystals Corn pression
Authors: HULSE CHARLES O. , PASK JOSEPH A.
Published: June 2006

Stress‐strain curves of single crystals of magnesia compressed in the [100] direction are reported at temperatures from –196° to 1200°C.; curves are also shown for different rates of loading at room temperature. The crystals show considerable ductility at all temperatures and at room temperature can be deformed plastically about 6% before fracture at stresses which are about one‐quarter of reported polycrystalline fracture strengths. The macroscopic yield drops apparently exponentially from an extrapolated value of 50,000 lb. per sq. in. at absolute zero to about 4500 lb. per sq. in. at temperatures of 900°C. and higher. Heat‐treatment has an appreciable effect on the yield stress. The resistance of the material to deformation increases with the number of slip systems and bands activated because of the barriers to dislocation movements which occur at slip band intersections. At about 2 to 3% strain, stress concentrations begin to be relieved by small internal cracks which are not easily propagated. This effect is extensive before final macroscopic failure of the crystal occurs. Preliminary creep tests above the macroscopic yield stress and in the temperature range 800° to 1000°C. show large instantaneous plastic deformations followed by slow constant‐rate creep.
Effects of Electron Bombardment on Properties of Various Glasses
Authors: MIKE T. M. , STEIERMAN B. L. , DEGERING ED. F.
Published: June 2006

Soda‐lime, borosilicate, and lead glass specimens were exposed to various dosages of 2 m.e.v. electrons. The effects of the irradiation on flexural strength, density, chemical durability, heat of solution, and electrical resistivity were investigated. The results showed that for dosages up to 300 megareps several small effects were noted but were considered to be of minor significance as far as bottle serviceability is concerned.
Effects of Electron Bombardment on Elasticity and Mechanical Damping of Certain Glasses
Authors: BARBER S. W. , FORRY K. E. , DEGERING D. F.
Published: June 2006

A borosilicate glass and a lead‐containing silicate glass have been exposed to various dosages of 2‐m.e.v. electrons, and the effects on the logarithmic decrement and period of a freely oscillating torsional pendulum in which each was made the torsional member have been noted. These effects, in both glasses, are qualitatively described as disannealing. Quantitatively, tan δ was increased 10 to 15% in the borosilicate and 30 to 60% in the lead glass, and the corresponding decreases in rigidity were of the order of 0.4 and 2%, respectively. In both glasses the mechanical effects and the associated brownish color anneal out in about 20 hours at 500°F. Besides these effects, there were some completely unexpected effects which are reported here for the first time and should be verified by others. These consist of (1) changes in the shape of tan δ vs. temperature curves caused not only by thermal treatment but also by changes in period of the pendulum and (2) fine structure in the tan δ vs. temperature maxima due to sodium ion diffusion. These details complicate the interpretation of such maxima and, if verified, will justify a re‐examination of the anelastic behavior of glasses in general and borosilicate glasses in particular.
Investigation of Some Glasses for High‐Level Gamma‐Radiation Dosimeters
Authors: HEDDEN W. A. , KIRCHER J. F. , KING B. W.
Published: June 2006

Several glass systems were evaluated as dosimeters to measure integrated doses in the range from 106 to 109 rads by measuring optical density as a function of radiation dose. The two more promising glasses of those studied were Corning's Code 8392 and a special high‐antimony glass. The maximum dosage that can be measured with these two glasses has not yet been determined. In exposures up to 3 × 108 rads, there was continuous increase in optical density with dose, and no evidence of saturation at the highest doses used. Glasses also were prepared that darkened only slightly at dosages up to about 8.7 × 107 rads. Such glasses may have utility for measuring dosages above 109 rads.
Thermoluminescence of Vitreous Germanium Oxide Containing the Impurity Aluminum
Authors: GARINO‐CANINA VITTORIO , COHEN SABATINO
Published: June 2006

The introduction of between 0 and 5% alumina into vitreous germanium oxide produces a thermoluminescence phenomenon after excitation by ultraviolet radiation which is characterized by (1) a peak position between 50° and 70° C. and (2) a peak height increasing with increase in the alumina introduced into the GeO2 glass.
Applications of Radiation Effects in Glasses in Low‐and High‐Level Dosimetry
Authors: BLAIR G. E.
Published: June 2006

Two types of dosimetry using special glasses as sensing elements are reviewed. Both systems give an integrated total dose measurement. One system is based on a change in luminescence with dose and covers the range 10 to 10,000 rads. The second system is based on an optical absorption change with dose and covers the range 104 to 107 rads.
Some Physical Properties of Thoria Reinforced by Metal Fibers
Authors: BASKIN Y. , HARADA Y. , HANDWERK J. H.
Published: June 2006

Values are presented for several physical properties of thoria reinforced by metal fibers. Properties determined at room temperature include compressive strength, modulus of rupture, and Young's modulus (dynamic method); those determined at elevated temperatures include modulus of rupture, Young's modulus, thermal conductivity, thermal expansion, and oxidation resistance. The widespread presence of fine cracks in reinforced thoria results in significantly lower strengths compared with thoria alone. The thermal conductivity of reinforced thoria is slightly greater than that of thoria at room temperature and the difference becomes more pronounced at elevated temperatures.
Separate Determination of Aluminum and of Lithium, Sodium, and Potassium in Fire‐Clay and Silica Raw Materials and Refractories by Cation‐Exchange Chromatography
Authors: OSBORN WALTON O.
Published: June 2006

Plant control dictates a need for a rapid accurate method for the determination of alumina in silica and fire‐clay materials. The determination of the alkali oxide impurities is also important. Given a finely ground sample representative of the lot of material in question, the chemist has two basic problems. He needs (1) an acceptable method for complete solubilization of the sample and (2) a simple and accurate method for the determination of the constituent sought. Ion‐exchange analysis permits both to be carried out with ease and precision in regard to alumina. For the alkalis the complete solubilization of all types of samples presents some problems, but ion‐exchange analysis is applicable to the second requirement. Solubilized samples are passed down through an ion‐exchange column of Dowex‐50 cation‐exchange resin perfused with the proper strength of HC1. The fractions are collected and the separated constituents are determined. Data are presented showing the results of various procedures as compared with accepted values for National Bureau of Standards samples.
Effect of Gamma Radiation on Spectral Transmission of Some Commercial Glasses
Authors: BARKER R. S. , RICHARDSON D. A.
Published: June 2006

An account is given of the effect of gamma radiation on the spectral transmission of certain commercial glasses. Curves are given showing the rate of fading of the coloration produced in these glasses by doses of gamma radiation in the range 104 to 108 rads. The effect on the optical density of some of these glasses by increasing doses of gamma radiation is discussed.
The System CaO‐Ga2O3
Authors: JEEVARATNAM J. , GLASSER F. P.
Published: June 2006

CaO and Ga2O3 form three compounds: 3CaO‐Ga2O3, CaO‐Ga2O3, and CaO‐2Ga2O3. 3CaO‐Ga2O3 melts incongruently to CaO plus liquid at 1263°C.; CaO Ga2O3 and CaO 2Ga2O3 melt congruently at 1369° and 1504°C. respectively. Eutectics are located at the following temperatures and compositions (in mole% Ga2O3): between 3CaO Ga2O3 and CaO Ga2O3, 1245°C. and 37.5%; between CaO Ga2O3 and CaO‐2Ga2O3,1323oC. and 57.0%; and between CaO ‐2Ga2O3 and β‐Ga2O3,1457°C. and 68.0%. There is a peritectic at 1263°C. and 36.0%. Three polymorphs of CaO Ga2O3 are described. Compositions from approximately 35 to 70 mole% Ga2O3 can be quenched to yield homogeneous glasses.
X‐Ray Strain Measurement Techniques for Ceramic Bodies
Authors: GROSSMAN LEONARD N. , FULRATH RICHARD M.
Published: June 2006

X‐ray diffractometer techniques for measuring triaxial and biaxial strain in ceramic bodies are described. The results of the techniques as applied to model ceramic systems using A12O3 and ThO2 crystal phases compacted with various glasses in the system Na2O‐B2O3‐SiO2 are presented. It is shown that internal stresses due to expansion coefficient mismatches occur in these systems and that their magnitudes often exceed the bulk strength of the body. Further applications of the techniques are discussed.
Fundamentals of Glass‐to‐Metal Bonding: V, Wettability of Iron by Molten Sodium Disilicate
Authors: CLINE ROBERT W. , FULRATH RICHARD M. , PASK JOSEPH A.
Published: June 2006

An experimental unit was developed to allow the application of the glass specimen onto the metal surface at elevated temperatures and under controlled atmospheric conditions. Sodium disilicate glass on Armco iron had a contact angle of 55°± 2° at 900° to 1000° C. in vacuum and poor adherence; on magnetite, 2°± 1°, and excellent adherence. Behavior on oxidized iron was affected by the ability of the glass to dissolve large quantities of oxide rapidly. Glass when dropped onto a lightly oxidized surface spread toward lower angles and retracted essentially to the 55° angle on solution of the oxide; adherence, in this case, correspondingly ranged from good to poor. When the glass dissolved a sufficient amount of iron oxide and etching of the metal occurred, resulting in the appearance of fayalite, the contact angle was in the range 15° to 35° and the best adherence was obtained. Vaporization of iron in vacuum at 1000°C. did not seem to be retarded by thin oxide films.
Ceramic Coatings with Controlled Reflective and Emissive Properties
Authors: BURGESS D. G. , JASPERSE J. R. , FLINT E. P.
Published: June 2006

Two types of ceramic coatings were formulated for application to Inconel to give (a) the highest possible emittance from room temperature to about 1200°C. and (b) the highest possible reflectance to solar energy (0.4 to 2.0 μ) while having high emissivity in the infrared from 25° to 700° C. or higher. Both types of coatings were formulated from a modified barium silicate frit. This frit was opacified with various black spinels to give the (a)‐type enamels having total normal emittances ranging from 0.74 to 0.87. The (b)‐type enamels were made with equal parts of stannic and eerie oxides as opacifiers. At thicknesses greater than 5 mils, these had hemispherical reflectances varying between 0.67 and 0.62 at wave lengths of 0.6 to 2.6 μ respectively, together with total emittances of 0.75 at 400°C. and 0.60 at 800° C.
Effect of Moisture in Furnace Atmosphere During Ground‐Coat Firing
Authors: BENZEL JAMES F. , UHER J. F. , ALLENBAUGH F. G. , SWEO B. J.
Published: June 2006

The effect of moisture content of the furnace atmosphere at different firing temperatures on the gases contained in ground‐coated specimens is evaluated by mass spectrometry. These results are compared with observed reboiling. There is a direct relation between moisture content of the furnace atmosphere and (1) reboiling and (2) hydrogen gases contained in the fired specimen. There is a direct relation between the firing temperature and the bubble structure of the fired specimen. No connection between moisture content of the furnace and the bubble structure can be established.
Colors and Magnetic Properties of Iron in Glasses of Various Types and Their Implicationsoncerning Structure: II, Cabal Glasses
Authors: BISHAY ADLI
Published: June 2006

The effect of changes in the glass structure on the colors and magnetic susceptibilities of iron was studied in glasses made of CaO, B2O3, and Al2O3 (cabal glasses). As the number of gaps in the structure increased, an increase in the general absorption and a decrease in magnetic susceptibility was observed and was attributed to ferrous iron in network‐forming positions. Further increase in the number of gaps was accompanied by a general increase in transmission as well as by an increase in magnetic susceptibility. This was attributed to the loosening of the structure around the ferrous iron which could easily escape from the interstices and be oxidized to colorless ferric iron taking network‐forming positions. The intensity of the ferrous band depended on the concentration of the ferrous iron and also was affected by the polarizing power of the neighboring cations.
Infrared Properties of Silicon Monox and Evaporated SiO Films
Authors: HOWARTH L. E. , SPITZER W. G.
Published: June 2006

This study is an investigation of the infrared properties of SiO in the wave‐length range 1 to 30 μ‐ The samples used in this study consisted of the commercially available bulk silicon monox and thin films made by evaporating this bulk material. Films which were made by evaporating onto a silicon substrate were used for transmission measurements. Reflectivity measurements as well as transmission measurements were made with the bulk material. From the foregoing data it was concluded that, although the bulk material is not SiO but rather a stoichiometric mixture of Si and SiO2, the evaporated films are a true amorphous SiO phase.
Transformation of Quartz to Cristobalite
Authors: CHAKLADER A. C. D. , ROBERTS A. L.
Published: June 2006

The transformation of quartz to cristobalite was studied in the temperature range 1400° to 1650° C. The process which was believed to be a direct one was found to be a consecutive reaction involving an intermediate transition phase. Both Madagascar and Brazilian quartz were used to study the transformation reaction. The reaction rate was found to be much faster for the Madagascar quartz than for the Brazilian quartz, although no difference in their impurity content was found in the spectrographic analysis. An approximate consecutive reaction kinetics was applied and the deviation of the experimentally observed values of the transition phase at a particular temperature from that of the mathematical prediction was noted and is discussed.
Phase Relations in the System Fe2O3–Fe3O4–YFeO3 in Air
Authors: VAN HOOK H. J.
Published: June 2006

Measurements were made of temperature and ternary composition for coexisting liquid and crystalline phases on the air isobar in the system Fe2O3‐Fe3O4‐YFeO3 with particular regard to the stability range and compositional limits of yttrium iron garnet. Phase equilibrium relations were determined by conventional quenching techniques combined with measurements of loss in weight at the reaction temperature to locate true ternary compositions. The intersection of the air isobar with the ternary univariant boundary curve for coexisting magnetite, garnet, and liquid phases results in a eutectic‐type situation at the composition Y0.27Fe1.73 O2.87 and 1469°± 2°C. A similar intersection of the isobar with the boundary curve for coexisting garnet, orthoferrite, and liquid phases gives rise to a peritectic‐type reaction at 1555° 3°C. and Y0.44Fe1.56 O2.89 The yttrium iron garnet crystallizing from liquids within these temperature and composition limits contains up to 0.5 mole % iron oxide in excess of the stoichiometric formula in terms of the starting composition 37.5 mole % Y2O3, 62.5 mole % Fe2O3. At 1470° C. the garnet phase in equilibrium with oxide liquid contains 2 mole % FeO in solid solution. The small solubility of excess of iron oxide and partial reduction of the garnet phase in air are unavoidable during equilibrium growth from the melt.
Polar‐Screen Theory for the Deflocculation of Suspensions
Authors: LEWIS ARTHUR E.
Published: June 2006

Deflocculation of suspensions results from the formation of surface charges on particles. The strongest charges are obtained by the hydrogen bonding of polar ions or molecules on particle surfaces. Measurements were made of the deflocculation of alumina in both polar and non‐polar liquids using various acids, bases, and electrolytes. The pH of suspensions was found to be temperature‐dependent, the pH decreasing with increasing temperature. The results of these experiments are not compatible with the double‐layer theory for the deflocculation of suspensions. The polar‐screen theory explaining deflocculation by the hydrogen bonding of polar ions or molecules to electronegative surfaces is presented. The polar ions or molecules provide the surfaces with a charged screen. Predictions are made on the basis of this theory and are experimentally verified.
Crystal Phases in the System Al2O3–AlN
Authors: LONG G. , FOSTER L. M.
Published: June 2006

Fused aluminum oxide containing a small amount of nitrogen (as added aluminum nitride) showed X‐ray powder diffraction patterns similar to the δ‐alumina obtained from the calcination of alumina mouohydrate in dry air. About 1% nitrogen was adequate for complete conversion of the α phase to the δ phase. A fused mixture containing 3.9% nitrogen showed a powder pattern identical to lithium ζ‐alumina.
Effects of Water Vapor on Oxidation of Silicon Carbide
Authors: JORGENSEN PAUL J. , WADSWORTH MILTON E. , CUTLER IVAN B.
Published: June 2006

The rate of oxidation of silicon carbide was studied at different partial pressures of water vapor. The diffusion‐rate constant was found to vary with the logarithm of the partial pressure of water vapor according to the theory of thin‐film oxidation as proposed by Engell and Hauffe. The products of oxidation were cristobalite and tridymite, depending on the temperature. The diffusing species appeared to be the same in the presence of partial pressures of water vapor and in the presence of partial pressures of oxygen.
High‐Temperature Mechanical Properties of Ceramic Materials: IV, Sintered Mullite Bodies
Authors: FENSTERMACHER J. E. , HUMMEL F. A.
Published: June 2006

An attempt was made to sinter relatively pure 3A12O3‐2SiO2 and 2A12O3‐SiO2 compositions to low porosities at 1710° and 1650°C, respectively, using an addition of 1% MgO to each body to facilitate the reaction. The 3A12O3‐2SiO2 body sintered to a porosity of 7.1% and was practically all mullite. The 2Al2O3SiO2 body sintered to a porosity of 10.9% and was composed of mullite and corundum. Strength and elastic modulus measurements were made at several temperatures up to 1200°C, and some observations of the load‐bearing properties were made.
Total Heat‐Transmission Coefficients of Amber and Green Glasses in Temperatures of Melting Range
Authors: KRUSZEWSKI S.
Published: June 2006

Measurements of an over‐all heat‐transmission coefficient for several commercial amber glasses were carried out in a pilot‐scale furnace at temperatures of the melting range. The data obtained were used in deciding depth and insulation of tank furnaces. It appears that the transmission of light of amber glasses in the near‐infrared range gives a practical indication of these heat‐transmission properties. The same pilot‐scale furnace was used to investigate the effect of chromium oxide, nickel oxide, and iron oxide on the over‐all heat‐transmission coefficients of green glasses. An empirical equation was derived, relating the heat‐transmission coefficient to the concentration of the coloring oxides. Of the three oxides, the effect of the nickel oxide on heat transmission is the strongest and the effect of the iron oxide is the weakest.
Transfer of Heat in Glass During Forming
Authors: McGRAW D. A.
Published: June 2006

The transfer of heat in glass during glass‐container machine‐forming operations is characterized by extremely high rates of heat removal from relatively thin sections of the material. Evidence is presented to show that, under these conditions, the transfer of heat within the glass is almost 100% by true conduction; the contribution of radiative transfer to the thermal distribution is almost nil. This conclusion was reached by the application of experimental forming and glass properties data to radiation and conduction theory through the use of a high‐speed digital computer. It is apparent further that the thermal conductivity of commercial container glass varies slowly with temperature in the forming range, increasing from about 14 B.t.u.‐ft.−2‐hr.−1‐in.1‐°F.−1 at 1200°F. to about 19 B.t.u.‐ft.−2‐hr.−1‐in.1‐°F.−1 at 2000°F. The heat‐transfer coefficient between glass and mold surfaces decreases rapidly with time of contact.
Changes in Microstructure of Chromite Spinel During Service
Authors: TREFFNER WALTER S.
Published: June 2006

A study has been made of the microstructure of chromite spinel and its changes in basic refractory brick under service conditions. Part of the changes occurring resemble those described previously for slag‐free environments, frequently enhanced by extended periods of exposure. In addition, slagging by solid, liquid, and vapor phases produces interesting new spinel micro‐structures in open‐hearth furnace roofs and checker systems, in various furnaces of the copper industry, in rotary kilns and glass‐tank checkers, and in regenerator walls.
Deformation Behavior of Polycrystalline Aluminum Oxide
Authors: WARSHAW STANLEY I. , NORTON FREDERICK H.
Published: June 2006

The steady‐state creep behavior of polycrystalline aluminum oxide from 97 to 100% dense has been examined at temperatures from 1600° to 1800°C over a range of stresses from 100 to 2000 psi under four‐point transverse bending. Grain size is shown to have an important effect on the deformation behavior. Stress‐strain rate dependence for the fine‐grained aluminum oxide (3 to 13μ) is of viscous behavior (°ε∼σ). The strain rate is also inversely proportional to the square of the grain size (°ε∼ 1/(GS)2). The creep behavior can be described by the Nabarro‐Herring diffusional flow model although the diffusion coefficient does not agree with that for oxygen diffusion in sapphire. When the grain size becomes coarse, the Nabarro‐Herring model no longer applies. Coarse‐grained aluminum oxide (50 to 100μl) behaves plastically when deformed (°ε∼σ). The strain rates observed on coarsegrained aluminum oxide are higher than one would predict from the deformation behavior of fine‐grained aluminum oxide. This plastic flow probably occurs through some dislocation movement or glide mechanism.
Studies in Lithium Oxide Systems: XII, Li2O‐B2O3‐Al2O3
Authors: KIM K. H. , HUMMEL F. A.
Published: June 2006

Tentative phase relations in the binary system BnOa‐A12O3 are presented as a prerequisite to the understanding of the system Li2O‐B2O3‐Al2O3. Two binary compounds, 2A12O3.B2O3 and 9A12O3.‐2B2O3, melted incongruently at 1030° f 7°C and about 144°C, respectively. Two ternary compounds were isolated, 2Li2O.A12O3.B2O3 and 2Li2O. 2AI2O3. 3B203. The 2:1:1 compound gave a melting reaction by differential thermal analysis at 870°± 20° C, but the exact nature of the melting behavior was not determined. The 2:2:‐3 compound melted at 790°± 20° C to LizO.‐5Al2O3 and liquid. X‐ray diffraction data for the compounds are presented and compatibility triangles are shown.
Properties of Soda Aluminosilicate Glasses: II, Internal Friction
Authors: DAY DELBERT E. , RINDONE GUY E.
Published: June 2006

Internal friction measurements of soda aluminosilicate glasses, the physical properties of which were reported in Part I of this series, are discussed. The low‐ and intermediate‐temperature internal friction peaks were studied in detail and are shown to be due to the stress‐controlled movement of the sodium and nonbridging oxygen ions, respectively. A close correlation was found between the temperature shift of the low‐temperature peak and the activation energy for electrical conduction in the soda aluminosilicate glasses. The magnitude of the low‐temperature peak was found to depend more on the structural environment of the sodium ions than on the actual soda content. Changes in the intermediate‐temperature peak are explained on the basis of the structural model proposed for these glasses.
Effect of Moisture in Furnace Atmosphere on Hydrogen Defects in Glass‐Coated Steel
Authors: SULLIVAN J. D. , NELSON D. H. , NELSON F. W.
Published: June 2006

Water vapor, present in a furnace atmosphere during the firing of glass‐coated steel, was evaluated as a source of defect‐producing hydrogen. Glass‐coating compositions having different fish‐scaling tendencies were fired on carbon steel coupons in specially designed laboratory apparatus. The furnace‐atmosphere dew point was varied from ‐90° to +120°F through the use of H20 and D2O. The residual hydrogen and/or deuterium of the coated steel was extracted and measured with a mass spectrometer. Results indicated that moisture in the furnace atmosphere was the greatest source of defect‐producing hydrogen in glass‐coated steel. Iron oxide on the surface of the steel decreased hydrogen absorption during firing. The iron oxide solubility of a glass‐coating composition was indicated to be related to the fish‐scaling tendency of the fired coating.
A Thermoviscoelastic Description of the Tempering of Glass
Authors: WEYMANN H. D.
Published: June 2006

The three‐dimensional equations for a Maxwell body and a Kelvin body are derived and supplemented to include thermal effects. The relations for the thermo‐Maxwell body are then applied to the tempering of infinite glass plates. An exact solution of the resulting differential equation is given in the form of a series expansion. For practical purposes more useful and easier to use are two solutions of the tempering differential equation in the form of approximations which are discussed in detail.
Behavior of Chromium in the System MgA12O4– A12O3
Authors: ARLETT ROBERT H.
Published: June 2006

Single crystals of chromium‐doped magnesium aluminate spinels with varying amounts of excess alumina have been grown by the flame fusion process. Presumably these crystals contain stoichiometrically significant amounts of defects. When these chromium‐doped spinels are annealed at temperatures below their melting point, the spinel structure cannot tolerate such a high concentration of defects and at least some of the excess alumina is exsolved. The chromium ion in magnesium aluminate spinel is pink, whereas in magnesium aluminate spinel containing excess alumina it is green. When exsolution of the alumina occurs during annealing, the aggregate changes to pink. The behavior of the chromium ion is monitored by observing the significant changes in the optical absorption as well as the emission or fluorescence spectra for both single crystals and polycrystalline materials in the system [MgA12O4– A12O3] :Cr.
Solid Solutions Based on Ferroelectric PbNb2,O6
Authors: SUBBARAO E. C. , HRIZO J.
Published: June 2006

An X‐ray and dielectric study of three series of PbNb2O6‐type solid solutions was carried out. The PbNbZOs‐type phase was present up to the following limits: (1) (Pb1−xBi4/3x)(TixNb2‐x.)O6, ×= 0.2; (2) (Pbl‐xBi43x)(Ti2Nbl—2)206, ×= 0.2; and (3) (Pb1−xBi2/3x)Nb2O6×= 0.3. Orthorhombic distortion b/a and Curie temperature decreased with increasing x. Bi4/3‐Ti206 was most effective in this respect and Bi2, 3‐Nb2O6 had the least influence. The important role played by ions of different valency located on crystallographically equivalent sites is pointed out.
Dielectric Properties of Glasses in the Systems Bi2O3‐CdO‐SiO2, Bi2O3‐CdO‐B2O3, and Bi2O3‐CdO‐GeO2 and Their Relation to the Structure of Glass
Authors: RAO BH. V. JANAKIRAMA
Published: June 2006

Areas of glass formation and regions of “neo‐ceramic” glasses in the systems Biz03‐CdO‐Si02, Bi203‐Cd0‐B203, and Bi203‐Cd0‐GeO2 are demarcated. Properties of glasses in the neoceramic regions were determined before and after nucleation and heat treatment. There are no maxima or minima in the dielectric properties versus composition curves. The dielectric constants increase after nucleation and heat treatment. The dissipation factors show a remarkable change toward higher values. Transparent glasses with Bi2O3. CdO as the predominant constituents have unusual dielectric constants ranging from 30 to 42 and dissipation factors ranging from 3 to 50 × 10−4., Since these glasses contain only from 0.5 to 2.0 wt% SiO2 or B2O3 or 5 wt% GeO2, the conventional concept of glass structure composed of a random spacial network of SiO4 tetrahedra, whose interstices are filled with network modifiers, cannot be sustained in this case. It is suggested that the dominant cations Bi3 + and Cd2+ form the network and that the interstices are occupied by Si4 + cations. The function of the Si4+ ion apparently is to distort the highly polarizable Bi3 + ion enough to form a random network. It appears to be possible that Bi3+ and Cd2+ can form the network in sixfold coordination. The dielectric losses observed are explained in terms of the relative instability of the structure.
Preliminary Studies in the System UC—PuC
Authors: LIED R. C. , WHITE G. D.
Published: June 2006

Plutonium monocarbide, uranium monocarbide, and 20 wt% plutonium‐80 wt% uranium monocarbide solid solution were prepared by reacting the respective oxides with carbon. Data are given on the densification, vaporization, chemical analyses, and X‐ray diffraction of the materials. Photomicrographs of microstructures are also presented.
Stability Relations of Magnesium Metasilicate Polymorphs
Authors: SARVER J. F. , HUMMEL F. A.
Published: June 2006

The observed stability relations of enstatite, protoenstatite, and clinoenstatite were in good agreement with the findings of earlier workers. Polycrystalline preparations of MgSiO3 polymorphs were synthesized with the aid of small additions of MgF2 or LiF as mineralizers. At 1042°± 3°C, enstatite, the stable low‐temperature modification, inverts to protoenstatite, the stable high‐temperature modification. The metastable transition between protoenstatite and clinoenstatite occurs at 865°± 5°C, the rate of transformation of polycrystalline protoenstatite to clinoenstatite being dependent on type and amount of mineralizer used, degree of compaction of sample, firing temperature, rate of cooling, degree of grinding at room temperature, and time at room temperature. Under certain conditions, a 1 to 2 mole % substitution of Mn2+ for Mg2+ inhibits the inversion of protoenstatite to either stable enstatite or metastable clinoenstatite below about 1042°C. Metastable clinoenstatite was never found to invert to the stable enstatite modification below the metastable inversion temperature of clinoenstatite to protoenstatite at 865°C. Above this temperature but below 1042°C, it inverts to protoenstatite which in turn inverts to enstatite. The aggregate linear thermal expansion coefficients of enstatite, protoenstatite, and clinoenstatite between 300° and 700° C were respectively 120 × 10−7, 98 × 10−7, and 135 × 10−7°C−1.