bluuebunny/crossref_metadata_2025 huggingface dataset:
Interface Reactions Between Glazes and the Crystal Phases in a High‐Talc Tile Body
Authors: PERRICONE A. C. , STONE ROBERT L.
Published: June 2006

A study was made to determine the glaze attack on several mineral phases found in a fired talc‐containing tile body. The effects of the chemical attack on the changes in the physical properties of the glaze were measured, using index of refraction and coefficient of expansion data. The glaze reaction at the interface was decreased when certain equivalents of BaO were substituted for PbO and when MgO replaced Na2O. Cristobalite showed greater solubility in the glaze than quartz, talc, or tremolite.
Studies on Formation and Recrystallization of Intermediate Reaction Products in the System Magnesia‐Silica‐Water
Authors: KALOUSEK GEORGE L. , MUI DANIEL
Published: June 2006

Mixtures of magnesia and silicic acid ranging in composition from 0.5 to 2.0 M/S were treated hydrothermally at temperatures of 75° to 350°C. for various periods of time. The reaction solids were examined by differential thermal analysis, X ray, and electron microscopy and analyzed chemically. The intermediate products of reaction ranging in composition between that of talc (0.75 M/S) and chrysotile (1.5 M/S) comprised a continuous series of cryptocrystalline needle‐like crystaIs matted tightly together and showing the same X‐ray pattern. The initial reaction product of the 0.75 to 1.50 M/S raw mixtures was a cryptocrystalline solid having a 1.5 M/S ratio. This phase subsequently reacted with the residual silica, so long as any was available, to form a solid having the composition of the raw mix, but only at relatively moderate temperatures(100°to175°C.). As the temperature was increased the crystals of the 0.75 and 1.50 M/S compositions increased in size, but all remained submicroscopic. The compositions intermediate between 0.75 and 1.5 M/S crystallized as mixtures of talc and chrysotilelike products. The chrysotilelike product appeared as minute needles which did not possess any apparent flexibility.
Thermal Analysis of Magnesite at CO2 Pressures up to Six Atmospheres
Authors: STONE ROBERT L.
Published: June 2006

The literature contains contradictory statements that the decomposition of magnesite is and is not affected by the pressure of CO2 during the decomposition reaction. By means of the new variable‐pressure differential thermal analysis technique, samples of Washington and Nevada magnesites were run at CO2 pressures over the range 0.001 to 5000 mm. Hg. At 0.001 mm. Hg the endothermic loop starts at approximately 350°C., at 500° C. for 1 atmosphere of CO2, and at 612°C. under 5000 mm. Hg pressure of CO2. The results permit straightforward analysis of the mechanics of decomposition and comply with the Clausius‐Clapeyron and Van't Hoff equations at CO2 pressures above 250 mm. Hg.
Experimental Study of Fracture of Glass:I, The Fracture Process
Authors: SHAND E. B.
Published: June 2006

A concept of fracture is developed from experimental data. Fractures are found to originate at flaws or cracks of finite size, most of which are at the surface. The mechanism is one of crack propagation which begins when the local stress at the crack exceeds a minimum value. The rate of propagation increases with crack growth until a critical stress is reached at the crack tip which coincides with a limiting crack velocity. This limiting condition is identified with the boundary of the mirror surface of the fracture. From calculations to be presented in Part 11, the critical stress is estimated to be several million pounds per square inch.
The Zirconia‐Titania System
Authors: BROWN FRANK H. , DUWEZ POL
Published: June 2006

A phase diagram for the zirconia‐titania system is proposed, based on the existence of a hitherto unreported compound, ZrTiOd. Thermal‐expansion and X‐ray diffraction experiments were performed on three series of specimens heated at 980°, 1370°, and 176O°C., respectively.
Study of Strains Between Enamel and Iron as Related to Physical Properties of Each
Authors: WALTON J. D.
Published: June 2006

The test methods used for measuring strains between enamel and iron are reviewed. The values obtained by each of these methods, as determined from the mechanics involved in producing the strains, are correlated with experimental data reported in the literature. The strains obtained from the split‐ring test are expressed in terms of the variables of enamel‐iron thickness and modulus of elasticity. These variables are graphically presented by means of a nomograph. Based on the strains obtained from the split‐ring test, a method is presented whereby the stresses responsible for the strains may be calculated. By determining the movement of a split ring under one condition of enamel‐iron thickness, the compressive forces developed within the enamel of different thicknesses and applied to various thicknesses of iron may be calculated.
Thermal Strains During Firing of a Ceramic Body
Authors: MITOFF STEPHAN P. , PASK JOSEPH A.
Published: June 2006

The tendency of a ceramic body to crack in firing owing to thermal stress was examined. Use was made of the physical measurement of three factors: (1) thermal gradient as affected by firing rate and thermal reactions, (2) coefficient of thermal expansion at each temperature, and (3) maximum strain, also a function of temperature. Each factor was determined individually during the firing of appropriate samples of a body consisting of 60% kaolin and 40% grog. Plastic flow was noted during the measurement of maximum strain. The effect of all these variables on the development of firing schedules was considered.
Viscosity Studies of System CaO–MgO–Al2O3–SiO3: IV, 60 and 65% SiO2
Authors: MACHIN J. S. , YEE TIN BOO
Published: June 2006

In this final paper of a series on viscosity in the system CaO—MgO‐Al2O3SiO2 data are presented for melts containing 60 and 65% SiO2. There also are diagrammatic presentations of the systems of isokoms at intervals on planes parallel to the zero alumina, zero lime, and zero magnesia faces of the tetrahedron, the apices of which represent 100% of each of the four oxides that make up the system.
A New Carbide‐Base Cermet Containing Tic, TiB2, and CoSi
Authors: GREENHOUSE HAROLD M. , STOOPS ROBERT F. , SHEVLIN THOMAS S.
Published: June 2006

A new high‐temperature material with excellent stress‐sustaining characteristics at 1800°F. has been developed. The weight per cent composition of this Tic‐base cermet is 55.4 TIC + 17.9 TiB2+ 16.7 Co + 10 Si, and the principal phases present after sintering are Tic, TiB2, and CoSi. The research on and development of this material and some of its physical properties are discussed.
Thermography of Gypsum
Authors: WEST RICHARD R. , SUTTON WILLARD J.
Published: June 2006

A study of gypsum was made using the differential thermal analysis technique. Gypsum and mixtures of gypsum with silica, alumina, iron oxide, dialyzed kaolin, or carbon were analyzed. Furnace atmospheres of air, nitrogen, carbon dioxide, and carbon monoxide were used. Gases evolved at the decomposition temperature of gypsum were analyzed chemically and sample residues were anelyzed by X‐ray diffraction A slight amount of decomposition was observed when gypsum passed from the beta to alpha mineral form of CaSO4, but decomposition was not complete even after fusion had started. The addition of 20% carbon to the gypsum and heating in a nitrogen atmosphere caused decomposition, with evolution of CO2 to start at a temperature as low as 615°C.
Silicon‐Base Cermets and Related Observations
Authors: WEBER B. C. , HESSINGER P. S.
Published: June 2006

Chemical reactions involving silicon in various atmospheres at elevated temperatures were studied. Formation conditions of silicon sub‐oxides were determined. Silicon‐base cermets in the systems silicon‐titanium dioxide and silicon‐titanium carbide were investigated along with combinations of titanium carbide and titanium silicides. The oxidation resistances of specimens were measured. Specimens were prepared by slip‐casting techniques involving no plasticizers.
Advances in Ceramics Related to Electronic Tube Developments
Authors: NAVIAS LOUIS
Published: June 2006

In some of the older vacuum tubes operating at 1‐mc. frequency or lower glass envelopes and porous ceramic refractories were used for internal supports. Some of the more modern electronic tubes operating at 10,000 mc. (3‐cm. wave length) require vacuum‐tight envelopes with (1) physical stability at operating temperatures (preferably a highly crystalline composition), (2) good mechanical strength, (3) surfaces which will take metallizing, (4) metal or alloy components of comparable thermal expansions, and (5) low dielectric losses, even after being heated in a reducing atmosphere such as hydrogen, or in a vacuum. After providing a brief historical background, the author discusses changes in properties of a few crystals and glasses and gives many detailed composition studies of four types of bodies, including such properties as linear thermal expansion and dielectric properties at 3‐cm. wave length, viz.: alumina, K 8.4, PF 0.0006; forsterite, K 6.3, PF 0.0006; zircon‐talc, k7.5, PF 0.0026; and steatite, K 6.6, PF 0.0005. A brief account is presented of the development of sealing techniques and some details are given for three modern methods of making ceramic‐metal seals by using (1) Mn‐Mo, (2) MoO3, and (3) TiH2 as the active metallizing agents.
Photographic Pyrometry
Authors: LONDEREE J. W.
Published: June 2006

Brightness temperatures were determined by measuring the densities of the photographic images produced by hot objects. Temperatures corresponding to these densities were obtained from film calibration curves. Each film was calibrated with exposures of a standard tungsten ribbon‐filament lamp. Within limits the calibration curves (film density vs. reciprocal temperature) were straight lines. The method is shown to be useful where an optical measurement of temperature is desirable but where conditions are changing too rapidly for measurement with the optical pyrometer. Continuous variations of temperature were recorded by moving the film behind a slit through which the image was focused.
Particle‐Size‐Distribution Analysis by a Modification of the Turbidimetric Procedure of Musgrave and Harner
Authors: LAMAR RICHARD S.
Published: June 2006

The turbidimetric method of determining particle‐size distribution, developed by Musgrave and Harner, has been modified and adapted for use with tales, clays, and similar nonmetallic minerals and ceramic raw materials. Results obtained by this method have been found to be reproducible to within ±2%, and check with those obtained by the Andreasen pipette method within the same limits of accuracy. The turbidimetric method is useful for the direct determination of sizes from 60 to 0.25μ, equivalent spherical diameter. The entire procedure for a complete particle‐size‐distribution analysis usually requires less than 1 hour as compared with several days for the analysis of similar materials by the pipette method.
Thermal Conductivity: XI, Conductivity bf Some Refractory Carbides and Nitrides
Authors: VASILOS T. , KINGERY W. D.
Published: June 2006

The thermal conductivity of Tic, Sic, TiN, and ZrN has been measured in the temperature range 100° to 1000°C. The thermal conductivity of these materials decreases with increasing temperature. Determination of the Wiedemann‐ Franz ratio indicates that electronic conduction is considerable for TIC, TiN, and ZrN but is small for Sic.
Industrial Diamond Substitutes: I, Physical and X‐Ray Study of Hafnium Carbide
Authors: COTTER PERRY G. , KOHN J. A.
Published: June 2006

A study of hard materials in an effort to find possible substitutes for industrial diamonds led to research on hafnium carbide. This compound was prepared from a mixture of hafnium dioxide and lampblack in a carbon resistance furnace by solid‐state reaction or from a melt. Some factors affecting the combined carbon content of the re‐ action products were qualitatively evaluated. A hafnium carbide prepared from a melt at a temperature slightly above 2800°C. with no holding time had a combined carbon content within 98% of the theoretical value. A curve was obtained by plotting combined carbon against cubic unit‐ cell dimension (a0) for the hafnium carbide‐ “hafnium monoxide” solid solution series. Extrapolation gave 4.641 ± 0.001 a.u. for the cell edge of hafnium carbide of theoretical composition; a0 was observed as high as 4.640 a.u. Density values within 99% of theoretical were obtained. Knoop microindentation hardness measurements with both dry and oil‐immersion objectives indicated a hardness in the silicon carbide range. Owing to its high cost and relatively low hard‐ ness, hafnium carbide is presently not considered to be a promising substitute for industrial diamonds.
Clay‐Particle Dispersion by Ultrasons
Authors: CROWLEY MICHAEL S. , PHILIP WELCH A.
Published: June 2006

The dispersion of 1.0% kaolin suspensions in water was studied utilizing ultrasonic vibrational energy. The effect of time of exposure to ultra‐sons was examined microscopically and turbidi‐metrically by means of a spectrophotometer. Complete deagglomeration and dispersion were accomplished in 10 minutes of exposure to ultra‐sons without any apparent deleterious effects on the primary particle size of the kaolin. The effects of two accepted methods of dispersion were compared with the ultrasonic method.
Infrared Spectra and Atomic Arrangement in Fused Boron Oxide and Soda Borate Glasses
Authors: ANDERSON SCOTT , BOHON ROBERT L. , KIMPTON DUDLEY D.
Published: June 2006

The infrared absorption spectra of fused B2O3 and of a series of soda borate glasses are presented. These spectra were obtained using vacuum‐pressed briquettes of the powdered glass and powdered KBr. The spectrum of fused B2O3 shows quite definitely that this glass does not consist of a completely continuous triangularly coordinative network. It is shown that hydrogen bonds play an important part in the atomic arrangement of the glasses of zero or low soda content. The B2O3 glass apparently consists of complexes of an approximate unit (B9O14)‐ held together by hydrogen bonds. One in nine borons is tetrahedrally coordinated. The glasses of low soda content are similar. The spectra for soda concentrations greater than 15% did not permit the determination of the atomic arrangement with exactitude, but it is shown to be quite different from that found in glasses with 10% Na2O or less.
Vibratory Compacting of Metal and Ceramic Powders
Authors: BELL WILLIAM C. , DILLENDER RICHARD D. , LOMINAC HAROLD R. , MANNING EDWARD G.
Published: June 2006

This investigation was concerned primarily with the forming of alumina, chromium‐alumina, and nickel‐titanium carbide powders by low‐frequency vibration. The effect of a wide variety of particle‐size distributions on the forming properties of these compositions was studied. An instrumentation system was developed for measuring the vibratory forces employed. Results obtained with various low‐frequency vibratory forming procedures are reported. Similar compositions were formed by dry pressing followed by hydrostatic repressing, and the properties of the specimens formed by the two methods are compared. The vibratory forming method offers a number of advantages over the hydrostatic method.
Determination of Strains in Enameled Cast Iron
Authors: WUELLNER J. F. , SWEO B. J.
Published: June 2006

A method of determining strains in enameled cast iron using a modification of the split‐ring furnace and employing cantilever‐type specimens is described. Strain curves of several cast‐iron enamels on cast‐iron cantilever‐type specimens are compared with results obtained on split rings. Strain curves are presented which show that cast‐iron enamels may craze at or close to the temperature of maximum tension of the enamels owing to the high degree of tensile strain in the enamels. This maximum tension can be increased by permanent growth of the cast iron.

The cast‐iron strip test as modified from the split‐ring test for sheet steel enamels serves as a more direct means of determining the strain existing between enamel and cast‐iron from room temperature to the softening point of the enamel. The cast‐iron strip test shows differences in cast iron enamels that have not been indicated by either the warp or split‐ring tests.

Cast‐iron enamels may craze at or close to the temperature of maximum tension, and this crazing is caused by the enamel being subjected to too high a degree of tensile stress during cooling. The degree of tensile strain is increased by the growth of iron which occurs if the temperature is held within, or moves too slowly through, the range of maximum tension of the enamel. By controlling the cooling rate, the strains in enameled cast iron can be altered.
Phase Equilibria in the System Lithium Metasilicate‐Forsterite–Silica
Authors: MURTHY M. KRISHNA , HUMMEL F. A.
Published: June 2006

The primary fields of cristobalite, tridymite, Li2O·2SiO2, Li2O·SiO2, MgSiO3, Mg2SiO4, and a new compound, Li2O·MgO·SiO2, have been located for the system lithium metasilicate‐forsterite–silica. Most of the primary field for the compound Li2O·MgO·SiO2 lies below the join Li2O·SiO2‐Mg2SiO4, but a small portion of it lies in the composition triangle Li2SiO3‐Mg2SiO4‐MgSiO3. The positions of four invariant points and three composition triangles have been established.
Relation Between Refractive Index and Density of a Glass at Constant Temperature
Authors: RITLAND H. N.
Published: June 2006

Data are presented on the changes in the room‐temperature refractive index and density of a borosilicate crown glass produced by different heat‐treatments. Measurements on a large number of samples with widely varying thermal history show that the refractive index is a single‐valued function of the density. The increase in refractive index for a given density change is smaller than that calculated by the Lorentz‐Lorenz theory; the apparent contribution of the induced polarization to the local electric field is very small. This may be due to a reduction in the ionic polarizabilities that accompany the density increase; alternatively, the Lorentz‐Lorenz form of the theory may not be valid in solid materials such as glass. Data of other investigators are shown to agree with the data reported here.
Effect of Oxygen Content of Furnace Atmosphere on Adherence of Vitreous Coatings to Iron
Authors: EUBANKS A. G. , MOORE D. G.
Published: June 2006

A series of porcelain enamel ground coats of the same basic composition but with various amounts of cobalt oxide was fired on enameling iron in atmospheres consisting of various oxygen‐nitrogen mixtures. The effect of the oxygen content of the atmosphere on adherence was determined and the effect on interface roughness was estimated from an examination of metallographic cross sections. A decrease in the amount of oxygen in the firing atmosphere necessitated an increase in the amount of cobalt oxide in the enamel if optimum adherence was to be secured. Ground coats containing 3.2% cobalt oxide or more developed a weak but definite bond in oxygen concentrations as low as 0.02 mole %. A qualitative correlation was found between adherence and surface roughness regardless of the oxygen content of the firing atmosphere.
Calcination of Calcite: I, Effect of Heating Rate and Temperature on Bulk Density of Calcium Oxide
Authors: FISCHER H. C.
Published: June 2006

High‐purity calcite of 10/20 mesh was calcined at various heating rates and fired to various maximum temperatures to determine the effect of these variables on the densification of the CaO produced. It was found that the heating rate during dissociation had a great bearing on densification. Shock heating conditions at temperatures between 2200° and 2530°F. gave bulk density values which were abnormally low.
Calcination of Calcite: II, Size and Growth Rate of Calcium Oxide Crystallites
Authors: FISCHER H. C.
Published: June 2006

The size and the growth rate of CaO crystallites were determined by X‐ray diffraction. The crystallites exhibited an extremely rapid rate of growth near 1650°F. Activation energies were obtained from the growth rates by means of the Arrhenius relationship.
Compressibility of Binary Alkali Borate and Silicate Glasses at High Pressures
Authors: WEIR C. E. , SHARTSIS L.
Published: June 2006

Isothermal compressibility data at 21°C. at pressures between 1000 and 10,000 atmospheres are reported for the binary alkali borate and silicate glass systems. In general, a decreasing compressibility is noted with increasing alkali content in both silicates and borates, the effect being much greater in the borates in the range of compositions studied. A maximum compressibility appears to be indicated for the potassium silicates at low potassium concentrations. In silicates and at high alkali contents in the borates, the order of compressibility is K > Na > Li. At low alkali contents in the borates, this order appears to be reversed. Possible interpretations of these data are discussed in terms of the concepts of the structura of glasses.
High‐Temperature Centrifuge for Separation of the Liquid Phase from Refractories: II, Centrifuging Tests
Authors: DERGE GERHARD , SHEGOG JACK
Published: June 2006

A rotating‐type induction furnace with graphite heater was used to demonstrate the application of the principles developed in Part I. Rotation at 1200 to 1300 r.p.m. for 15 minutes at an average temperature of 2560°F. (1405°C.) separated a low‐melting slag from a silica brick which had been used in an open‐hearth roof.
Adjustment of Thermal Expansion of Cone 8 Glazes
Authors: VAN GORDON D. V. , SPANGENBERG W. C.
Published: June 2006

Shivering of cone 8 zirconium‐opacifled glazes for use on one‐fire pyrophyllite wall tile and warping of the tile body were corrected by increasing the thermal expansion of the glazes. This was accomplished by (1) increasing the alkali content, (2) substituting strontium oxide for zinc oxide, (3) substituting calcium oxide for magnesium oxide, and (4) decreasing the silica‐alumina ratio. The last method appeared to be the most effective. It is shown that the calculated coefficient of cubic thermal expansion is often unreliable as a value for the actual expansion. Expansions were obtained with a quartz‐rod dilatometer.
Sintering Experiments on Sapphire Spheres
Authors: NAVIAS LOUIS
Published: June 2006

The plastic‐flow theory of sintering between particles has been suggested and verified by several investigators. Tiny spheres in contact should develop a lens or bridge between them due to capillary action. Such contact lenses have been observed by others in materials such as NaCl, Cu, and stabilized ZrO2. They were unable to find contact lenses in pure ZrO2 or Al2O3. A simple technique has been developed whereby a contact lens or bridge is obtained between 40‐mil spheres of sapphire by heating them on a thin molybdenum saucer held on a molybdenum block by induction in a vacuum (or in hydrogen).
Aids in Hydrothermal Experimentation: II, Methods of Making Mixtures for Both “Dry” and “Wet” Phase Equilibrium Studies
Authors: ROY RUSTUM
Published: June 2006

Various methods for the preparation of mixtures for phase equilibrium studies are described. Especial attention has been paid to compositions which cannot be preserved in a glass structure.
Physical and X‐Ray Study of the Disilicides of Titanium, Zirconium, and Hafnium
Authors: COTTER PERRY G. , KOHN J. A. , POTTER R. A.
Published: June 2006

A method of preparing the disilicides of titanium, zirconium, and hafnium is outlined. Unit‐cell dimensions, density, Knoop microhardness numbers, chemical analyses, and solubility in various reagents are given for the three compounds. It is concluded that these disilicides have no value as industrial hard materials.
Development of Safe Cooling Schedules for Structural Clay Products
Authors: LACHMAN IRWIN M. , EVERHART J. O.
Published: June 2006

A method is described whereby safe cooling schedules for structural clay products are developed, based on a criterion for thermal failure. Resistance to thermal failure may be indicated by the following equation: Resistance =MR a/Ea, where MR is the modulus of rupture, E is the modulus of elasticity, a is the thermal diffusivity, and a is the coefficient of linear thermal contraction. The modulus of rupture, modulus of elasticity, linear thermal contraction, and relative thermal diffusivity of three commercial bodies were measured in the temperature range 1600°F. to room temperature. Using the experimental values, relative cooling schedules are developed in terms of ware temperature versus dimensionless time, the total time for cooling being a function of size and shape. The order of importance of the physical properties is discussed with respect to cooling schedules and it is concluded that the coefficient of linear thermal contraction has the greatest effect. The mechanisms acting in clay bodies during cooling are discussed and the idea of quartz separation is presented. The hysteresis of the modulus of elasticity and coefficient of thermal expansion while heating and cooling is correlated with quartz separation and the literature is cited to support the idea. Some tests are described to show that rebonding of the quartz occurs on reheating to sufficiently high temperatures.
Flame Spectrophotometric Analysis of Glasses: II, Calcium, Magnesium, and Barium, Including the Alkalis
Authors: WILLIAMS J. P. , ADAMS P. B.
Published: June 2006

The amount of calcium, magnesium, and barium, as well as of the alkali elements, in many glass compositions can be rapidly estimated with a flame spectrophotometer. Since the flame emission of the alkaline‐earth elements is altered by such glass constituents as aluminum, iron, titanium, phosphorus, and zirconium, these elements should be removed, before flame analysis, by precipitation with ammonium hydroxide. With the elimination of the hydrous oxides and with corrections for the background interferences in the flame emission of the alkaline earths by the elements remaining, satisfactory flame analyses can be obtained. The mean difference between chemical and flame results for a series of 27 glasses of widely varying composition is approximately 0.15% for each element determined.
Some Physical Properties of High‐Density Thorium Dioxide
Authors: LANG S. M. , KNUDSEN F. P.
Published: June 2006

The values for a number of physical properties are reported for a very high density form of thorium dioxide. When specimens of a mixture of 99½% ThO2 and ½% CaO, by weight, were hydrostatically pressed at 30,000 lb. per sq. in. and heat‐treated for 1 hour at 1800°C., they attained 99.0% of theoretical density. All the test specimens were extremely brittle. Physical‐property values determined at room tempera‐ ture were the following: lattice constant; bulk and theoretical (X‐ray) densities; compressive and impact strengths; Knoop hardness; modulus of rupture and Young's modulus, determined by a static method; Young's modulus and the shear modulus, determined by a dynamic method; Poisson's ratio and the bulk modulus, calculated from the dynamic‐test data; and the velocity of sound through the material. The properties determined at elevated temperatures were the following : linear thermal expansion modulus of rupture and Young's modulus, determined by a static method; Young's modulus and the shear modulus, determined by a dynamic method; and Poisson's ratio, calculated from the elevated‐temperature dynamic‐test data. “Martin's diameter” grain counts were taken for the material both before and after heat‐treatment.
Formation of Manganese Ferrite by Solid‐State Reaction
Authors: KEDESDY H. H. , TAUBER A.
Published: June 2006

An investigation has been made of the formation of manganese ferrite by solid‐state reaction from mixtures of Mn3O4 and Fe2O3 in a 1 : 3 mole ratio, employing four different firing cycles. The solid‐state reaction was observed by means of X‐ray diffraction, optical microscopy, mass analysis, and differential thermal analysis. Magnetic parameters were determined from hysteresis hop and permeability measurements. The formation of solid solutions of manganese oxide and ferric oxide, which precedes the ferrite formation, was studied in detail. Surface oxidation and exsolution in ferrite bodies cooled slowly from high temperatures were studied by optical microscopy and X‐ray diffraction.
Thermal Expansion of Various Ceramic Materials to 1500°C
Authors: WHITTEMORE OSGOOD J. , AULT NEIL N.
Published: June 2006

Thermal‐expansion data from room temperature to 1500°C. are given for a number of ceramic materials. Determinations were made with telemicroscopes on bars or rods 7 in. long
Cermets: I, Fundamental Concepts Related to Micro‐structure and Physical Properties of Cermet Systems
Authors: HUMENIK MICHAEL , PARIKH NIRANJAN M.
Published: June 2006

The microstructure of tungsten carbide and titanium carbide base cermets has been evaluated on the basis of wettability of the carbide phase. Incomplete wetting was found to result in a coalescence of the carbide phase leading to an apparent increase in the carbide particle size. Improvement in the wettability of the nickel‐titanium carbide systems by the addition of molybdenum was found to promote the dispersion of the carbide phase and to lead to improved hardness and impact resistance.
Note on Failure of Ceramic Materials at Elevated Temperatures Under Impact Loading
Authors: KINGERY W. D. , PAPPIS J.
Published: June 2006

The failure of Al2O3, MgO, Pyrex‐brand glass, soda‐lime‐silica soft glass, and a triaxial semi‐vitreous whiteware body under impact loading has been observed in some cases from room temperature to 1600°C. The pendulum energy required to fracture these materials remains constant or decreases with temperature over the temperature region of possible use.
Barite in Ceramic Whitewares
Authors: RUSSELL RALSTON , VALENCIA CAMILO , EMRICH H. W.
Published: June 2006

An investigation was made of the thermal behavior of natural barite (barium sulfate) and of its effect as a major constituent in whiteware bodies. The maturing characteristics and fired properties of twenty‐five barite bodies were compared with those of two conventional semi‐vitreous bodies. Barite bodies were found to be particularly promising for the production of semi‐vitreous and nonvitreous ware. They exhibited maturing ranges three to eleven times greater than the maturing ranges of conventional semi‐vitreous bodies and relatively uniform properties when fired over wide temperature ranges. It appears that an essentially new field of unusual ceramic whitewares has been discovered.
Solder Glass Sealing
Authors: DALTON ROBERT H.
Published: June 2006

The development of low‐melting solder glasses which make possible the sealing of ordinary glasses at temperatures near their annealing point is described. The properties required of such solder glasses are discussed and some compositions which meet these requirements are given. The high‐lead region of the system PbO‐B2O3‐Al2O3‐SiO2 is taken up in detail. The effect of the addition of ZnO to this system is also considered. Devitrification is a problem in the use of some of these glasses. The technique of applying the solder glass in various types of seals is described. The advantages and disadvantages of this kind of sealing are pointed out.
Thermal Decomposition of Manganous and Ferrous Carbonates
Authors: KISSINGER H. E. , MCMURDIE H. F. , SIMPSON B. S.
Published: June 2006

The mechanism of decomposition of manganous and ferrous carbonates has been explored by high‐temperature X‐ray diffraction in controlled atmospheres, by differential thermal analysis, and by thermogra vimetric analysis. The heat effects of the series of reactions which occur are calculated from thermochemical data. The heat effects observed in differential thermal analysis agree reasonably well with the calculated heats of the proposed reactions. The manner in which the techniques used in obtaining differential thermal analysis patterns may affect the results is discussed.
Determination of Resistivity of Lossy Materials from Dielectric Measurements, Making Use of Interfacial Polarization
Authors: LEWIS ROBERT T. , BICKFORD LAWRENCE R.
Published: June 2006

It is a well‐known fact that the phenomenon of interfacial polarization complicates dielectric measurements at low frequencies. This effect leads to a pseudo‐Debye relaxation process in a frequency or temperature spectrum of dielectric constant and loss, with the relaxation time determined by the physical dimensions of the barrier layer and by the resistivity of the bulk material. Use of this effect has been made to determine the resistivity of glass by purposely introducing a barrier of known dimensions, in the form of a thin sheet of mica. Values of resistivity and activation energy obtained by this method agree with values obtained by direct‐current measurements.
Reactions in the System Li2O‐MgO‐Al2O3‐SiO2: II, Phase Equilibria in the High‐Silica Region
Authors: PROKOPOWICZ T. I. , HUMMEL F. A.
Published: June 2006

Liquidus and subsolidus relationships were determined for compositions lying on the 65 and 75% SiO2 planes in the quaternary tetrahedron. From these data and from additional data on several compositions not lying on these two planes, a picture of the probable positions of the phase volumes and quaternary invariant points was formulated. Solid solution effects in quartz and in β‐spodumene, the polymorphism of MgSiO3, the phase relationships along the join Li2O ‐MgO ° SiO2‐Li2O. Al2O3.2SiO2, and the location of the β‐spodumene‐mullite boundary were briefly investigated as subsidiary problems during the course of the work. The significance of the data with respect to ceramic bodies and glazes is discussed.
The Emissivity of Transparent Materials
Authors: GARDON ROBERT
Published: June 2006

The emission of thermal radiation by transparent materials is reviewed from first principles and is compared with the more familiar emission of radiation by opaque surfaces. The comparison leads to an expression for volume emissive power, which is an important concept for discussions of radiative effects in glass. The present treatment differs from that of McMahon in that it takes account of the diffuse character of radiation. As a result, it also constitutes a simple proof of the often overlooked fact that the radiant flux within a transparent radiator exceeds that emitted into air by a factor approximately equal to the square of the refractive index. Using these concepts, the spectral emissivities of isothermal transparent sheets are expressed in terms of their thickness and the optical properties of their materials. The results are illustrated by a discussion of the total hemispherical emissivities of sheets of window glass at various temperatures. The commonly accepted value of about 0.91 is the same for all glasses having a refractive index of 1.5. However, it applies only for sheets above a certain minimum thickness. For window glass this ranges from 3/16 in. at 200°C. to as much as 8 in. at 1000°C. At 1000°C. a sheet 3/16 in. thick has an emissivity of only 0.59. The application of results to calculations of the radiative cooling of transparent sheets is briefly indicated.
Ceramic Properties of Samarium Oxide and Gadolinium Oxide; X‐Ray Studies of Other Rare‐Earth Oxides and Some Compounds
Authors: CURTIS C. E. , JOHNSON J. R.
Published: June 2006

Samarium oxide forms a ceramic of medium strength and density (6.0) when it is fired at 1300°C. When it is fired at 1500°C., its density is increased to 7.4 but it loses its stability toward boiling water. X‐ray data are given concerning the structure of the oxide as received and at 1300°C. and of the reaction product of Sm203 with water. Gadolinium oxide forms a ceramic of somewhat higher density (7.0) at 1300° than does Sm2O3; at 1500°C. its density is slightly higher (7.6) whereas its stability toward water is unchanged. Data concerning both oxides include density, shrinkage, moduli of elasticity and of rupture, linear thermal expansion, differential thermal analysis, and specific heat as well as X‐ray data. Results are given of a brief survey of the reaction products obtained when Sm2O3 and Gd2O3 are heated at 1500°C. in equimolecular quantities with Al2O3, BaO, CaO, CdO, Fe2O3, HfO2, MgO, SO2, SrO, ThO2, and ZrO2. X‐ray data for the following rare‐earth oxides as received and after calcination at 1400°C. are given: ceria, praseodymia, neodymia, europia, dysprosia, holmia, erbia, thulia, and ytterbia.
Ceramic Crucible for Melting Titanium
Authors: WEBER BERTHOLD C. , THOMPSON WILLIAM M. , BIELSTEIN HANS O. , SCHWARTZ MURRAY A.
Published: June 2006

Research studies have resulted in the development of an oxygen‐deficient zirconia material modified in a novel way to make it thermally stable and inert to molten titanium. It is possible to melt titanium in crucibles of this material with no significant increase in hardness. However, limitations regarding overheating and soaking must be taken into account.
Phase Equilibria in the System BaTiO3–SrTiO3
Authors: BASMAJIAN J. A. , DeVRIES R. C.
Published: June 2006

Phase equilibria in the binary system BaTiO3–SrTiO3 were studied above 1200°C. This system is characterized by a complete series of solid solutions with a minimum at 2.5 mole % SrTiO3 and 1585°C. The hexagonal BaTiO3 phase is suppressed to a region extending no farther than 0.5% SrTiO3 at 1600°C. No immiscibility gap was found.
Characterization of Sinterable Oxide Powders: I, BeO
Authors: QUIRK J. F. , MOSLEY N. B. , DUCKWORTH W. H.
Published: June 2006

The discovery of readily sinterable BeO powder facilitated the production of dense, high‐strength BeO ceramics and created interest in the properties and preparation of sinterable BeO. BeO powders prepared by the thermal decomposition of Be(OH)2 were studied in an effort to relate sinterability with other more basic characteristics of the oxide powder. Different BeO powders made from analyzed hydroxides showed a wide range of sinterability. The temperatures required for sintering the powder compacts to theoretical density ranged from 2300° to above 3200°F. Lattice parameters, thermal decomposition, surface areas, and refractive indices were determined on these powders after calcination in air at 750°, 1470°, 1830°, and 2190°F. Although unexpected variations in these properties were observed, no simple relation with sinterability was found. Occluded and surface impurities appeared to have a critical effect on sintering behavior.
Phase Equilibrium Relationships at Liquidus Temperatures in the System FeO–Fe2O3–Al2O3–SiO2
Authors: MUAN ARNULF
Published: June 2006

Phase equilibrium data at liquidus temperatures are presented for mixtures in the system FeO–Fe2O3–Al2O3–SiO2. The volume located between the 1 and 0.2 atm. O2 isobaric surfaces of the tetrahedron representing this system was studied in detail. Scattered data were obtained at lower O2 pressures. Results obtained in the present investigation were combined with data in the literature to construct a phase equilibrium diagram, at liquidus temperatures, for the entire system FeO–Fe2O3–Al2O3–SiO2. Methods for interpretation of the diagram are explained.
Glass Formation
Authors: WINTER A.
Published: June 2006

The ability to form a glass, i.e., the ability to form bonds which lead to a vitreous network, appears periodically in the classification chart of the elements. Thus simple glasses containing only one kind of atom are formed by the elements of Group VI of the periodic table (O, S, Se, and Te). Only these elements are known to form monatomic (primary) glasses and they retain the ability to form a vitreous network when mixed or chemically bound to each other. The elements of Group VI also form binary glasses, i.e., glasses containing two kinds of atoms, with the elements of Groups III, IV, and V. Experimental evidence of the glassforming capacities of these elements and compounds is given; about twenty new glasses suggested by the foregoing were prepared in the author's laboratory. Binary glasses are also known to exist composed of an element of Group VII (F, Cl, I, or Br) and an element of one of Groups II, III, and IV or a transition element. Experimental evidence for these glasses is presented.
Role of Grain Boundaries in Sintering.
Authors: BURKE J. E.
Published: June 2006

During sintering, grain boundaries act either as sinks or as diffusion paths for lattice vacancies. Thus the configuration of the grain boundaries will have an important effect on the rate of sintering. Grain growth during sintering changes the configuration of grain boundaries relative to pores and thus may markedly influence the shrinkage rate; for example, for uniformly distributed pores the shrinkage rate will increase as the grain size decreases. Impurity additions will increase the sintering rate if they increase diffusion rates, but they may also increase sintering rates by impeding grain‐boundary movement. Some experimental evidence is presented to support these conclusions.
Dielectric Studies in the System CdO‐Nb2O5
Authors: de BRETTEVILLE A. , HALDEN F. A. , VASILOS T. , REED L.
Published: June 2006

Results of studies on the effect of compositional changes and impurities on the electrical characteristics of single‐crystal, hot‐pressed, and dry‐pressed and fired cadmium niobate are presented. Specimens of compositions from CdNb2O6 to Cd2.1Nb2O7.1 were studied optically, electrically, and by X‐ray diffraction. Cadmium metaniobate remains paraelectric from –180° to +400°C. and acts primarily as a diluent to the ferroelectric properties of cadmium niobate. The Curie point of cadmium niobate occurs at approximately –85°C. with a dielectric constant peak of 6600 for a [110] crystal cut. Indications of antiferroelectricity are discussed. Room‐temperature measurements in the paraelectric phase at 21 kilomegacycles indicate a dielectric constant of 150 with a dissipation factor of less than 0.002 as compared with the high losses of BaTiO3 in this frequency range.
Fundamentals of Glass‐to‐Metal Bonding: II, Reactions of Tantalum and Sodium Silicate Glass
Authors: MITOFF STEPHAN P.
Published: June 2006

A compound, identified by X‐ray diffraction analysis as sodium metatantalate (Na2Ta2O6), was found at the interface between a sodium silicate glass and tantalum metal which had been heated in vacuum to 1000°C. Thermodynamic calculations, followed by further experimental evidence, were used to determine the chemical reaction between tantalum and sodium silicate which resulted in the formation of Na2Ta2O6. The compound was synthesized by other methods and its structure was investigated.
Effects of Ceramic Parameters on Microwave Properties of Nickel Ferrite
Authors: BLUM S. L. , ZNEIMER J. E. , ZLOTNICK H.
Published: June 2006

A simple apparatus is described for measuring the magnetic loss as a function of magnetic field for ferrites at a frequency of 10,000 mc. The width of the ferromagnetic resonance curve is as important a factor in designing microwave devices as is the resistivity of these materials. The method of preparing ferrites and the physical properties of polycrystalline nickel ferrites as affected by preparation and firing techniques are discussed. It is shown that pores in the ferrite body substantially increase the width of the ferromagnetic resonance curve. The direct‐current resistivity can be made to vary from 10 ohm‐cm. to 109 ohm‐cm. by changing the firing temperatures. The variation in the relative permeability with the bulk density of the body is discussed with reference to domain rotation and domain wall movement.
Properties of Some Calcium Aluminate Cement Compositions
Authors: GITZEN W. H. , HART L. D. , MacZURA G.
Published: June 2006

The properties of some high‐purity calcium aluminate cement compositions in that portion of the lime‐alumina system from 64 to 86% alumina were investigated. The laboratory preparation of seven hydraulic compositions in this system is described. Methods of appraising the properties, both in the neat cement and in castable formulations, are given. Data on bond strength, setting properties, heat of hydration, refractoriness, and aging characteristics are presented. A cement composition represented by the empirical molar formula CaO 2. 5Al2O3 was found to be optimum for balanced bond strength and refractoriness in high‐temperature castables.
Activities in Borosilicate Melts: I, Some Melts in the System CaO–B2O3
Authors: KNAPP W. J. , FLOOD H.
Published: June 2006

Several types of structural models were evaluated for some calcium borate melts by calculating melt activities. The calculated activities were compared with values determined from calorimetric heats of fusion. An ionic model was the most valid for the melts studied. The presence of (BO2)33– rings in melts of calcium metaborate was indicated.
Structure of Borate Glasses
Authors: HUGGINS MAURICE L. , ABE TOSlO
Published: June 2006

Anomalous thermal expansion and other properties of borate glasses have previously been given a structural explanation by Abe. This explanation is here reinterpreted and revised in terms of the structon theory of Huggins. In agreement with Warren, it is postulated that, in glasses containing, in addition to boric oxide, small relative amounts of an alkali or alkaline‐earth oxide, some of the boron atoms are surrounded by four oxygen atoms and all the oxygen atoms bridge between two boron atoms. At concentrations beyond that of the thermal expansion minimum, some oxygens are assumed to have only one boron neighbor. These ideas are formulated quantitatively and are used to interpret pertinent experimental data. From the concentrations where the property‐composition curves show breaks, conclusions may be drawn as to the average number of oxygens surrounding each metal atom.
Phase Equilibria in the System CaO‐Iron Oxide in Air and at 1 Atm. O2 Pressure
Authors: PHILLIPS BERT , MUAN ARNULF
Published: June 2006

Phase equilibrium data, obtained by the quenching technique, are presented for mixtures in the iron oxide‐rich part of the system CaO‐iron oxide in air and at 1 atm. O2 pressure. Present data are combined with data available in the literature to construct phase diagrams comprising the region from liquidus temperatures to temperatures slightly below the solidus.
Optical Properties of Diatomic Glasses
Authors: WINTER A.
Published: June 2006

The ability of elements to form glasses, the leading part played by the elements of Group VI (O, S, Se, and Te), and the possible influence of the elements of Group VII (F, Cl, Br, and I) are discussed. New glasses suggested by previous work were melted and the refractive index (n) and coefficient of dispersion (v) of some of them were measured. Inspection of the n, v plots of oxide, sulfide, selenide, and telluride glasses shows that the area corresponding to them extends toward high values of refractive index (nmax= 5.3) and low values of dispersion coefficient (vmin=4).
Detection of Reaction Products Between Water and Soda‐Lime‐Silica Glass
Authors: WANG FRANKLIN FU‐YEN , TOOLEY F. V.
Published: June 2006

A simulated extract approach was used to ascertain the identities of the products of reaction between a soda‐lime‐silica glass and water. The reaction between the glass and water was studied at 90° C. with reaction time periods up to 4 hours. The products of this reaction were found to be sodium metasilicate, calcium meta‐silicate, and metasilicic acid.
High‐Temperature‐Resistant Ceramic Adhesives
Authors: LEFORT HENRY G. , BENNETT DWIGHT G.
Published: June 2006

Ceramic adhesives were developed for bonding metal in the operational range 500° to 1000°F. When glassy‐bond adhesives were suitably prepared and properly applied to types 302 and 17–7 PH stainless‐steel specimens, shear strengths of the order of 2000 lb. per sq. in. were obtained at a test temperature of 800°F. and shear strengths of more than 800 lb. per sq. in. were obtained at 1000°F. Factors affecting adhesive strength included thermal‐expansion fit between ceramic adhesive and metal, metal or metallic oxide additions to the adhesive glass, and the use of metal screens of selected wire and mesh dimensions as carriers in the adhesive joint. The ceramic adhesive could be applied to a precipitation hardenable type of stainless steel during part of the precipitation hardening treatment, which included heating the metal for various times at temperatures up to 1750°F.