bluuebunny/crossref_metadata_2025 huggingface dataset:
Investigation of Structure of Glasses by Their Infrared Reflection Spectra
Authors: ANDERSON SCOTT
Published: June 2006

Infrared reflection spectra of a number of glasses are presented. It is apparent that in some cases such a method may be a useful tool in determining the atomic arrangement in glasses, especially when combined with quantitative measurements of the refractive index and extinction coefficient. The dispersion curves of barium‐containing silicate glasses show that the network of these glasses contains metals in at least two different types of coordination. One is obviously the silica tetrahedron and the other is probably a octahedrally coordinated barium. The latter is concluded by comparison with the reflection spectrum of benitoite. Reflection spectra of boric oxide glasses are presented. These indicate that pure boric oxide glass is not 100% triangularly coordinated and that the pure glass contains much more tetrahedral coordination than was previously concluded from X‐ray‐scattering data.
Dielectric Properties of Lead Zirconate and Barium‐Lead Zirconate
Authors: ROBERTS SMEPARD
Published: June 2006

Methods are described for preparing lead zirconate and mixtures of lead and barium zirconate in ceramic form. These compositions are shown to constitute a new class of ferroelectric materials having dielectric constants as high as 11,000. Dielectric constants are measured at 1 mc. per second in a temperature range 25° to 350° C. Nonlinear dielectric properties and piezoelectric effects are demonstrated.
Fundamental Study of Phosphate Bonding in Refractories: I, Literature Review
Authors: KINGERY WILLIAM DAVID
Published: June 2006

The literature on phosphate bonding in refractories is reviewed. Phosphate bonding is accomplished by three major methods: (1) the use of siliceous materials with phosphoric acid, (2) the use of oxides with phosphoric acid, and (3) the direct addition or formation of acid phosphates. Except for dental cements, no data on bond mechanism are available. Except for metaphosphate additions, no systematic study of phosphate bond properties has been made.
II, Cold‐Setting Properties
Authors: KINGERY WILLIAM DAVID
Published: June 2006

Experimental data indicate that cold‐setting bonds may be farmed from oxide‐phosphoric acid reactions, from phosphate‐phosphoric acid reactions, or by direct addition of liquid phosphate bond. In all cases acid phosphates are responsible for the bonding action. For optimum bonding, a weakly basic or amphoteric cation having a moderately small ionic radius is required so that a nonordered structure can be formed. The solidification process for a liquid phosphate bond has been determined. No weak temperature zone appears on heating these bonds because of the gradual loss of “combined” water and the gradual crystallization of the dehydration products.
Direct Gravimetric Determination of Aluminum with 8‐Hydroxyquinoline
Authors: KASSNER JAMES L. , OZIER MARY ALICE
Published: June 2006

Aluminum is determined by precipitating it with 8‐hydroxyquinoline in an ammoniacal solution containing tartrate, cyanide, and hydrogen peroxide. The method makes possible the direct precipitation of aluminum in the presence of all the substances normally found in the “mixed oxides” commonly called R2O3. The procedure has been successfully applied to synthetic samples containing iron and titanium and to National Bureau of Standards samples of clay, bauxite, and a fired refractory. The precision of the proposed procedure is about 0.5 part per 1000 and the accuracy is about 0.08%.
Some Studies on the Solarization of Glass
Authors: WHITE J. F. , SILVERMAN W.B.
Published: June 2006

This work covers the visible light transmission changes due to solar and high‐pressure mercury‐arc radiation for a soda‐lime glass when 0.15% of As2O3, CeO2, MnO2, and Sb2O3 are added. Each oxidizing agent exhibits characteristic color change after irradiation and Sb2O3 shows least color change. Effects of ultraviolet radiation on transmission in the infrared and ultraviolet are given. Differences in the depth of penetration of the color change for solar and arc radiation are pointed out. Replacement of Na2O or K2O by Li2O causes radical reduction in color change from mercury‐arc radiation. A Li2O ‐BeO‐SiO2 glass exhibits no color change when subjected to mercury‐arc radiation.
Changes in the Tensile Strength of Glass Caused by Water Immersion Treatment
Authors: STOCKDALE G. F. , TOOLEY F. V. , YING C. W.
Published: June 2006

An investigation was undertaken to determine quantitatively the effect of water immersion on the tensile strength of three commercial glasses. Test specimens were prepared by drawing sodalime, lead, and borosilicate glass rods down to constricted sections 0.011 to 0.012 in. in diameter. Substantial quantities of these carefully prepared constricted rods were broken in air and under water after varying periods of treatment in distilled water at 90°C. Breaking strengths of the test specimens are compared with strengths obtained on control specimens stored in a desiccator during the test periods. This comparative technique furnishes the most valid basis for comparison of results because the effects of any systematic errors in specimen preparation are minimized. Strength decreases of about 12% were found when freshly prepared specimens were broken under water. Extended water soaking treatments at 90°C. gave strength increases greater than 100% for the borosilicate glass. Interpretations of these results are discussed on the basis of the flaw theory of the weakness of glass.
A Study of Spalling Found in Porcelain Enamel After Repeated Freezing and Thawing in the Presence of Moisture
Authors: McEVOY R. J. , ANDREWS A. I.
Published: June 2006

A study was made of the spalling defect found on porcelain enamel liners in cold‐wall domestic refrigerators. A test machine was built to duplicate the environment of the enamel in the moist compartment of the cold‐wall type box. The test machine held ten 1‐ft.‐sq. test panels. The panels were fastened to freezing coils in the same manner as in a commercial box. A trough kept at a constant level of water provided the moisture. The thawing of the plates was done by ten 250‐watt heat lamps, each lamp focused on a test panel. The lamps were wired synchronously with the refrigeration circuit. It was found that enamels with a low bubble structure were superior in their spall resistance. Titanium enamel appeared better than other types, particularly when a clay of the kaolin type was used as the suspending agent.
Interference Films on Glass
Authors: ANDERSON SCOTT , KIMPTON D. D.
Published: June 2006

The change in refractive index and thickness of the leached film on a high barium‐silicate glass in 3N HCL has been studied as a function of etching time and temperature. The thickness change follows the form αt–βt2 where t represents the time of leaching. The refractive index decreases for a time and then increases with thickness increase. Some evidence is found that indicates the stain layer forms by a region of low refractive index moving into the glass.
A High‐Temperature Vacuum Induction Furnace
Authors: SMYTH HAROLD T. , MEINKEN ROBERT H. , WISNYI LEONARD G.
Published: June 2006

A furnace has been developed for use in a program of high‐temperature measurement of physical properties. The heat is developed by induction in a molybdenum or tantalum tube located inside a helix of water‐cooled copper tubing. Power is supplied from a vacum‐tube high‐frequency generator. The entire furnace is enclosed in a brass shell and operated in vacuum.
Diffusion of Ions in Some Simple Glasses
Authors: JOHNSON JAMES R. , BRISTOW ROBERT H. , BLAU HENRY H.
Published: June 2006

An investigation of the diffusion of ions in several glasses was made using radioactive tracer techniques. The resulting diffusion curves were analyzed to obtain the thermodynamic properties of the diffusion process. These properties are indicative of energy and structure changes in the glass networks. Interpretations of the results are advanced.
The Catalytic Effect of Kiln Atmosphere on Adsorption and Moisture Expansion of Fired Whiteware Bodies
Authors: SANDFORD FOLKE
Published: June 2006

The influence of various kiln atmospheres, including 10% CO + 90% N2, CO2, O2, N2, air, and steam, on unglazed bodies of vitreous china, and also on calcareous and other types of earthenware has been investigated in regard to (1) sorption isotherms for water vapor, and (2) elongation and increase of weight when treated with steam at 354°F. for 1 hour in an autoclave. The different kiln atmospheres were found to exert notable effects on these characteristics of the fired ware.
The Construction and Operation of Thoria Resistor‐Type Furnaces
Authors: LANG S. M. , GELLER R. F.
Published: June 2006

This paper describes in detail the construction, operation, and approximate cost of furnaces heated with oxide resistors of the Nernst filament type consisting essentially of thoria. The furnaces have been operated at temperatures up to 2050°C., with an atmosphere of air in the heating chamber.
Calcination Studies of Magnesium Oxides
Authors: EUBANK WILLIAM RODERICK
Published: June 2006

Magnesium carbonate, basic carbonate, and hydroxide were calcined at temperatures of 300° to 2000°C. for periods ranging from 120 hours at the low temperatures to a few minutes at the higher ones. The resulting magnesium oxides were studied by means of X‐ray powder diffraction and electron and petrographic microscopy. Only the cubic, periclase, crystal structure for MgO was observed. A small increase in the size of the unit cell was noted, however, for oxides obtained by low‐temperature calcination. Calcination of magnesium compounds was observed to take place in two distinct steps: (1) loss of gases at temperatures of 300° to 500°C. and (2) recrystallization or sintering at temperatures above 900°C. At the lower temperatures the loss of gases leaves a very porous structure with a large internal surface area and great reactivity (adsorptive power). Lattice dilation and imperfection is considered to account in part for the observed properties.
Effects of Chemical Additions on the Hydration Rate of Fired Quicklime (CaO)
Authors: CAHOON H. P. , JOHNSON P. D.
Published: June 2006

The effects of various oxide additions to specially prepared lime briquettes fired to 1625° and 1750°C. for 1‐ and 4‐hour periods are described as rates of hydration of the final product. The tests indicated that Fe2O3 was most effective in the reduction of the hydration rate. The method of incorporating the additive also controlled this rate. The studies included 1% increments up to a total of 5% of the following materials: Fe2O3, Cr2O3, V2O5, MnO2, CoO, TiO2, NiO, and Ca(PO3)2. Other oxides used without any noticeable effects were MgO, ZnO, Tho2, ZrO2, and SnO2.
A Method for the Measurement of Thermal Diffusivity of Molten Glass
Authors: VAN ZEE A. F. , BABCOCK C. I.
Published: June 2006

Thermal diffusivity data have been obtained on two typical soda‐lime‐silica glasses in the temperature range from 700° to 1400°C. The thermal diffusivity of a typical glass increases exponentially from 0.016 at 700° to 0.21 cm.2 per second at 1400°C. The measurement gives the total heat transferred by both conduction and radiation. The glass sample is held in a long crucible having cylindrical symmetry. A small sinusoidal temperature variation is superimposed on the mean temperature of the sample, and the time lag for the sinusoidal heat wave to travel radially from a point on the circumference of the sample to the center is measured. Furnace construction, method of controlling sinusoidal heat input, and methods of measurement are described.
Flame‐Fusion of Synthesis of Several Types Silicate Structures
Authors: BAUER W. H. , GORDON I.
Published: June 2006

The flame‐fusion technique is feasible for the growth of many anhydrous silicates. Successful syntheses were accomplished in four of the five classes of the general structural classification of silicates. There are several advantages for this type of growth technique, and an ideal opportunity is presented thereby for controlled experimentation in the study of natural and artificial crystalline structures, solid‐solution series, and the effects of minor additions.
A High‐Lime Refractory Resistant to Phosphate Melts—Studies in the System CaO–TiO2
Authors: FISK HENRY G.
Published: June 2006

Refractory crucibles, resistant to phosphate melts, were prepared from lime bonded with calcium titanate. The crucibles exhibited good spalling resistance and a relatively good stability to the slaking action of the atmosphere, indicating the possibility of other uses for the crucibles. It was found that the calcium titanate forming the bond in the crucibles and the protective coating on the lime grains has a lime content greater than the 1:1 ratio, probably 3CaO.2TiO2. The petrographic and X‐ray characteristics of this titanate are described.
Glaze Investigations: I, Effect of Various Silicas in Typical Glazes
Authors: RUSSELL RALSTON , ROWLANDS ROBERT R.
Published: June 2006

Four types of silica, namely potter's flint, diatomaceous earth, chalcedony, and fused silica, plus pyrophyllite, were substituted in typical fritted, Bristol, and porcelain glazes. After firing over a wide range of temperature, the following glaze characteristics were evaluated: maturing temperature, maturing range, surface texture, defects, and glaze fit. Results indicate that diatomaceous silica is decidedly superior to the other silicas as a primary glaze constituent. Chalcedony and fused silica also appear promising, whereas potter's flint and pyrophyllite are less satisfactory sources of constituent silica for glaze compositions.
Note on Decomposition of Glass by an Acid‐Leaching Solution
Authors: DICK E. F. , LOREY G. E. , SKINNER R. D. , SIMPSON H. E.
Published: June 2006

A method for determining the comparative rates of release of the soluble elements in glasses to an acid‐leaching solution (0.02 N HCl) was studied. The solution was run through a column of powdered glass at a temperature of 50°C. Soda and silica removed from the surface of the glass were determined by spectrographic analysis. By successive analyses of the leaching solutions, curves were obtained showing the amounts of soda and silica removed. Determinations were made on three glasses typical of those used in the flat glass industry: a plate glass and two window glasses.
Single‐Number Tolerances for Colored Glass Specifications
Authors: KREIDL NORBERT J. , PETT TYLER G.
Published: June 2006

Chromaticity data of glasses were measured by the Hunter Color‐Color Difference Meter and the results converted to single numbers representing distances in color space between each glass and a glass in the center of an appropriate specification. This simple evaluation gave as good a correlation to visual specifications as the more complicated evaluation of spectrophotometric data. A probable error of 5% existed for each method if the alternate method was regarded as correct. It was found that 1¾ Hunter units of color difference were equivalent to 1½ judds in a specification for a moderate yellow green series.
Anelasticity of Glass: IV, Correlation of Electrical Strain with Mechanical Strain in Glass
Authors: FITZGERALD J. V.
Published: June 2006

The residual charge and anomalous absorption current reported for certain glasses can be explained by making reference to internal friction peaks caused by the stress diffusion of sodium or potassium ions. When an electrical potential gradient or “electrical stress” is applied to any of these glasses, the “induced electrical strain” is associated with the time‐consuming formation of a new equilibrium distribution of sodium ions.
Determination of Boric Oxide in Glass by Direct Titration
Authors: WEBSTER P. A.
Published: June 2006

The work reported by Hollander and Rieman1, 2 is used as the basis for an improved procedure for quantitative determination of B2O3 in glass. After fusion, interfering elements are removed, and B2O3 is titrated with standard alkali in the presence of mannite. The procedure is rapid and accurate, making it particularly suitable for routine work.
High‐Temperature Bodies Derived from Mixtures of Mgo‐TiN‐NiO
Authors: HOWER L. D. , LONDEREE J. W. , UELTZ H. F. G.
Published: June 2006

Mixtures formulated from MgO‐TiN‐NiO were investigated in a search for a high‐temperature refractory material. Components were selected on the basis of their physical and chemical properties. Sintering was performed in a protective argon atmosphere. NiO was reduced or dissociated to nickel metal during the sintering operation. Titanium nitride was introduced to promote a bond between the metallic phase, nickel metal, and the ceramic oxide, MgO. Data is presented for three compositions evaluated for transverse strength, resistance to oxidation expressed as per cent weight gain, and thermal shock in terms of transverse strength. Several compositions exhibited increased transverse strength after being exposed to an oxidizing atmosphere.
Fundamental Study and Equipment for Sintering and Testing of Cermet Bodies: V, Fabrication, Testing, and Properties of 30 Chromium–70 Alumina Cermets
Authors: BLACKBURN A. R. , SHEVLIN T. S.
Published: June 2006

A cermet composition of 70% alumina–30% chromium has given very promising results as a new high‐strength, refractory material. Bodies of the alumina‐chromium composition with a particle size of 10 p and less were prepared and fabricated into test specimens under very closely controlled conditions of milling, pressing, and sintering. The fabricated specimens were tested in the laboratory, and results indicate that the material is extremely hard and resistant to oxidation and has outstanding strengths both at room and at elevated temperatures. Resistance to thermal shock indicates limited application possibilities, and impact resistance is low.
Differential Thermal‐Analysis Studies of Ceramic Materials: III, Characteristic Heat Effects of Some Sulfates
Authors: GRUVER R. M.
Published: June 2006

Differential thermal‐analysis studies were made of the thermal behavior of some sulfates used in the ceramic industry. Thermal‐analysis curves indicated the temperature of crystallographic inversions, decompositions, or melting points within the range room temperature to 1500°C.
Investigation of the Adherence of Glass to Metals and Alloys
Authors: DARTNELL R. C. , FAIRBANKS H. V. , KOEHLER W. A.
Published: June 2006

This investigation made use of the kinetic adherence test devised by Kapnicky1 for testing the adherence of molten glass to heated metal samples. This testing apparatus attempts to simulate the conditions of the automatic forming machines of the glass‐container industry. Several commercially pure metals and alloys plus a carbon‐iron series were run for their adherence temperatures. It was found that as the per cent carbon in iron was increased the adherence temperature was decreased. Heat‐treating of a modified brass sample decreased its adherence temperature. Persistence tests were run using tungsten, nickel, and Monel with clear and amber soda‐lime glass. The persistence test consisted of holding the temperature of the metal constant below its adherence temperature and dropping molten glass beads on the heated metal surface until adherence occurred. The amber glass used gave higher persistance values than the clear soda‐lime glass, although the adherence temperatures checked very closely. Monel metal heated to 900°F. gave a persistence of more than 800 molten glass contacts using amber glass at the rate of one glass contact per minute.
Islanding—A Surface Characteristic of Some Porcelain Enamels
Authors: BLANCHARD M. K. , DERINGER W. A.
Published: June 2006

The observations made during an investigation of a porcelain enamel surface characteristic called “islanding” are presented. The appearance and characteristics of islanded enamel surfaces are described and possible modes of formation are considered. Results of corrosion tests on islanded and nonislanded surfaces are included to show the nonhomogeneity of some porcelain enamels.
A Method for Determining Young's Modulus of Glass at Elevated Temperatures
Authors: McGRAW D. A.
Published: June 2006

Because of the experimental difficulties imposed by the prominence of delayed elastic and viscous effects, little investigation has been made of the instantaneous elastic modulus of soda‐lime‐silica glasses above approximately 500°C. The method described in this paper provides a means of measuring the Young's modulus of such glasses. The method is applicable from room temperature to 680° or 700°C. The sample, a cylinder of glass encased in a thin‐walled metal tube, is mounted vertically in a furnace and bent as a cantilever beam by horizontal application of load at the top of the sample. The instantaneous deflection of the composite rod is measured and recorded by a suitable extensometer and oscillograph circuit. Young's modulus is calculated from the difference between the load‐deflection characteristics of the composite sample and those of an empty tube of the same metal. Data are presented for three soda‐lime‐silica glasses in the range 25° to 700°C.
Long‐Time Load Tests on Commercial Classes of Fire‐Clay Brick
Authors: CROOKSTON J. A. , TORGESON D. R.
Published: June 2006

The load‐bearing characteristics of commercial superduty, high duty, and siliceous fire‐clay classes of refractories were studied and the results discussed in terms of optimum testing methods and possible service applications. Standard 9‐in. straights were tested, using an electrically heated (Globar) furnace designed to permit simultaneous testing of two brick placed on end. The brick were subjected to a load of 25 lb. per sq. in., and the continuous vertical linear change was measured with revolving‐drum kymographs. The brick were tested under the following conditions (a) 11/2‐hour hold at 2460°F., (b) 24‐hour hold at 2400°F., (c) 100‐hour hold at 2200°, 2400°, and 2500°F., and (d) 500‐hour hold at 2200°F.
Oxidation Products Which Contribute to the Oxidation Resistance of Tic‐Base Cermets
Authors: GREENHOUSE HAROLD M.
Published: June 2006

The oxidation of Tic‐base cermets can be minimized if two processes are stopped: (1) diffusion of oxygen into the cermet body and (2) diffusion of cermet components through the oxide to the oxide‐air interface. Two methods of curtailing these diffusion processes are considered: (1) the formation of an amorphous glassy oxide and (2) the formation of oxidation products which enable certain types of crystalline oxides to occur in a definite order. Both these methods are discussed by means of representative examples. The cermet TiC‐TiB2‐CoSi represents the first method; the cermet (Ti, Ta, Nb)C + Co represents the second method.
Properties of Graphite
Authors: HOWE JOHN P.
Published: June 2006

The structure, thermal properties, electrical characteristics, and mechanical behavior of graphite are reviewed and the highly anisotropic character of graphite crystals is emphasized. The interesting properties of graphite are due in large measure to the strong semimetallic bonds between carbon atoms in plane layers and to the relatively weak binding between planes. Details of its structure are due in part to the Frank dislocation mechanism for growth of crystals. Thus graphite has a low vapor pressure and approximately two‐dimensional electrical and thermal conductivity. It is easily deformed in slip on the basal plane, but in polycrystalline form it is relatively strong at high temperature. Its lamellar nature is emphasized by its reaction with alkali metals and bromine.
Relations Among Certain Specification Properties of Building Brick and Effects of Differences in Raw Materials and Methods of Forming
Authors: McBURNEY J. W. , RICHMOND J. C. , COPELAND M. A.
Published: June 2006

Strength, absorption, and saturation‐coefficient relations were analyzed on 3205 brick whose individual properties were reported in Building Materials and Structures Report BMS60. These brick included examples of all commercial types of forming and represented a wide range of raw materials. The analysis consisted of classifying the specimens into groups throughout a range of one property and calculating the averages of other properties thus associated. Similar analyses were made of subgroups selected on the bases of raw material and method of forming. Plotting these averages gave smooth and regular curves for the relation of one property to another. Characteristic differences among the relations of certain properties were found among groups classified according to raw material and method of forming.
Relative Importance of Various Sources of Defect‐Producing Hydrogen Introduced into Steel During the Application of Porcelain Enamels
Authors: MOORE DWIGHT G. , MASON MARY A. , HARRISON WILLIAM N.
Published: June 2006

Deuterium (heavy hydrogen) was used to trace the source of defect‐producing hydrogen in steel. The deuterium was introduced, in turn, as a replacement for protium (regular hydrogen) in the pickling acid, the milling water, the quenching water, the chemically combined water in the clay, and the dissolved water in the frit. The gases evolved during fishscaling of the coated steel specimens from each experiment were collected and analyzed for deuterium and protium with the mass spectrometer. The data showed that the principal source of defect‐producing hydrogen was the dissolved water in the frit. Experiments in which the presence or absence of lifting and fishscaling served as criteria confirmed the tracer work. Other experiments demonstrated that reboil in ground‐coat enamels is closely associated with the water content of the coating.
Fundamental Study of Clay: XII, A Note on the Effect of the Surface Tension of Water on the Plasticity of Clay
Authors: SCHWARTZ BERNARD
Published: June 2006

The effect of lowering the surface tension of water on the plasticity of a clay was evaluated from stress‐strain diagrams. Lowering the surface tension decreased the yield point, maximum strength, and workability of the plastic clay. A theoretical explanation for these phenomena is presented.
Fundamental Study of Phosphate Bonding in Refractories: IV, Mortars Bonded with Monoaluminum and Monomagnesium Phosphate
Authors: KINGERY WILLIAM DAVID
Published: June 2006

Mortar compositions containing monoaluminum phosphate and monomagnesium phosphate have been investigated. Five compositions developed have been tested for workability, water retention, strength, shrinkage, and appearance in mortar joints at temperatures up to 1500°C. Results obtained indicated that these mortars are equivalent to or superior to commercial mortars for which comparable data are available in the literature. It was found that retardation of phosphate bond migration by ground clay decreased bond strength.
Apparatus for Differential Thermal Analysis Under Controlled Partial Pressures of H2O, CO2, or Other Gases
Authors: STONE ROBERT L.
Published: June 2006

An apparatus was designed so that an atmosphere (a continuously flowing atmosphere) containing any partial pressure of the active vapor such as H2O, CO2, or SO3, could be maintained around the particles of a mineral powder while the differential thermal analysis was being run. The sample holder and its attendant parts were mounted on a movable vertical shaft so that the assembly could be lowered into or raised out of the furnace. The gas was carried to the powders under very slight pressure through 1/2‐in.‐diameter porcelain tubes, called the injector, which fit snugly into the sample holder cavities. The bottoms of the cavities were the ends of two 4‐hole porcelain tubes which carry the thermocouples and also support the sample holder. Two types of sample holders were used, (1) Inconel tubes, 1/2 in. in outside diameter and 3/4 in. long with a wall thickness of 0.008 in., and (2) a solid Inconel block 3/4 in. in diameter and 3/4 in. long with two symmetrically placed holes 0.234 in. in diameter drilled parallel to the length. These sample holders accommodate about 0.15 gm. of clay or 0.20 gm. of alumina as the reference material. There were four 28‐gauge thermocouple wires in each cavity. In the sample cell, two wires were one leg of the differential couple and the other two wires were dummies to balance the cell. In the reference cavity were the other leg of the differential couple and the measuring couple. All four wires in each cell were fused into a single bead and the wires were spread as far apart as possible, forming a sturdy unit. The furnace was 41/2 in. square and 5 in. long with an Alundum tube core, 11/16 in. in outside diameter, on which 45 ohms of 28‐gauge Nichrome V wire was noninductively wound. A motor‐driven Powerstat was used to control the temperature rate at 16°C. per minute.
Differential Thermal Analysis of Kaolin Group Minerals Under Controlled Partial Pressures of H2O
Authors: STONE ROBERT L.
Published: June 2006

Differential thermal analyses of samples of Kamec (N. C.) kaolin, Tako (Ala.) kaolin, an English kaolin, dickite (Ouray, Colo.), halloysite (Eureka, Utah), and diaspore (Chester, Mass.) were run under dynamic conditions in atmospheres containing water vapor of known partial pressures ranging from 5.0 to 760 mm. The differential thermal analysis curves of all kaolins showed the first indication of dehydration (that is, the beginning of the endothermic peak) at about 400°C., the halloysite at 320°C., the dickite at 500°C., and the diaspore at 465°C. in dry air. In steam atmosphere, the starting temperatures of the endothermic peaks were 470°, 485°, 585° and 510°C., respectively. The peak temperatures of the endothermic peaks were only slightly affected by the atmospheres, hence the peaks were more intense and covered a narrower temperature spread in the steam atmosphere. All kaolin‐group minerals showed the exothermic peak at 1000°C. in dry air and 970° to 980°C. in steam atmosphere. The data on In p H2O vs. 1/T for each mineral were plotted according to the van't Hoff equation. The straight line of dickite above In p H2O = 5.30 was used to calculate the heat of dehydration. The value is 137 cal. Per gm. The van't Hoff lines for the kaolinites and for diaspore, although straight lines, are in error since the recorded temperatures are considerably above the equilibrium temperatures because the rates of reaction are too slow at or near equilibrium. Actually kaolinite will decompose extremely slowly in the dry air at about 250°C., but in the steam atmosphere it will not decompose until about 475°C.
Experimental Refractory Bodies of High‐Melting Nitrides, Carbides, and Uranium Dioxide
Authors: CHIOTTI P.
Published: June 2006

A procedure for the preparation of the nitrides and carbides of several metals and the preparation of refractory bodies from them is described. The investigation shows that reasonably strong and dense bodies can be prepared from these materials as well as from UO2. Evidence showing the tendency of Be3N2, TaN, and ThN toward instability at high temperatures is presented. Evidence is also given indicating that the hexagonal structure reported by others for TaN is actually that for Ta2N. A lattice for Th2N3 is proposed. The melting points of ThN, UN, and UC are determined to be 2630 ± 50°C., 2650 ± 100°C., and 2590 ± 50°C., respectively.
Wetting of Al2O3‐SiO2 Refractories by Molten Glass: I, Measurement of Wetting
Authors: COMEFORO J. E. , HURSH R. K.
Published: June 2006

The wetting of alumina‐silica refractories by a soda‐lime‐silica glass at 1200°C. was studied by taking measurements from enlarged photographs of a glass drop on the refractory surface after various time intervals. The values calculated for the contact angles were in agreement with those obtained by direct measurement of the solid‐glass‐air interfaces. A review of the theoretical considerations validating the use of the contact angle as a means of measuring the wetting tendency is presented. The physical conditions which can influence the magnitude of the contact angle are also discussed, as is the method of calculating the contact angle. The rate at which the contact angles decreased indicated that an appreciable difference exists in the tendency of the molten glass to wet the various alumina‐silica refractories. A comparison is made of the wetting behavior of the refractories studied.
Reactions of Sodium Sulfate with Alumina‐Silica Refractories
Authors: LAMBERTSON WINGATE A.
Published: June 2006

By measurements of loss of weight, checked by water extraction of unreacted salt, it was found that at high temperatures liquid sodium sulfate reacts with mullite more rapidly than with alumina. A study of the structures involved explains this. Nephelite is the principal product of reaction. Experiments indicate that the resistance of high‐alumina firebrick to soda attack can be improved with a refractory coating, particularly one composed of alumina, nephelite, and sodium aluminate.
Composition of Low‐Alkali Glass
Authors: YOSHIKI BUMPEI , YOSHIDA RYOZO
Published: June 2006

This research was performed with a view to manufacturing a new chemical‐ware glass with no boric oxide content. A glass composition which contains little alkali and which melts easily, following the ternary melting diagram of albite‐diopside‐wollastonite, was produced. This low‐alkali glass shows little difference in practical melting and workability from ordinary borosilicate glass. Its water resistivity is even higher. Production of this glass on an industrial scale has been accomplished by utilizing natural rocks yet unexploited and using no soda ash at all.
Annealing of 517: 645 Borosilicate Optical Glass: II, Density
Authors: KREIDL NORBERT J. , WEIDEL ROBERT A.
Published: June 2006

The density of a 517:645 optical borosilicate glass increased by more than 1% when samples quenched from the highest temperature at which no further decreases in density were observed were annealed at the lowest temperature at which increases were observed within reasonable time. Conversely, stabilization times increased with decrease of stabilization temperature. This behavior was in agreement with that exhibited by this and other glasses in respect to other properties. The increase in density caused a much smaller increase in refractive index than expected from conventional refraction‐density relations. This was interpreted to mean that in glasses packed to a high density, the specific refraction decreased in relation to the tightening of the electronic structure. It may then be said that the refractive index of a fine annealed glass was the result of two opposing trends‐the increasing density tended to increase it, the decreasing specific refraction indicative of a tight and less responsive electronic system tended to decrease it. The net result is the moderate increase observed in previous studies.
Fluoride Model Systems: II, The Binary Systems CaF2–BeF2, MgF2–BeF2, and LiF–MgF2
Authors: COUNTS W. E. , ROY RUSTUM , OSBORN E. F.
Published: June 2006

Data obtained by quenching, thermal, and high‐temperature X‐ray techniques are presented for the three binary systems CaF2–BeF2, MgF2–BeF2, and LiF–MgF2. The systems CaF2–BeF2 and MgF2–BeF2 are presented as weakened models of the systems ZrO2–SiO2 and TiO2–SiO2, respectively. The compound CaBeF4 is a model of ZrSiO4 (zircon). New data obtained for the system LiF–MgF2 explain many discrepancies among the results of previous authors. Solid solution is almost complete between LiF and MgF2 at elevated temperatures, but a small gap occurs at the eutectic (735°C.) with extensive exsolution at lower temperatures.
Factors Influencing Premature Failure of Ceramic Digester Linings in Sulfite Pulp Mills
Authors: KELLY HAL J. , MAINHARDT ROBERT , STRANDBERG KARLE G.
Published: June 2006

Improved resistance to forces that destroy digester lining brick was made possible by careful firing to achieve a delicate balance between (a) strength and acid resistance and (b) thermal shock or fatigue resistance. To determine this balance, bulk density, modulus of elasticity, and acid resistance were established as reliable criteria. Of the brick now being used, those having a bulk density of 2.17 or more with a modulus of elasticity of 2.6 × 106 1b. per sq. in. indicate optimum firing. Similar brick, prepared in the laboratory, successfully withstood laboratory tests simulating digester conditions and are now undergoing final testing in actual service.
Viscosity and Electrical Resistivity of Molten Alkali Borates
Authors: SHARTSIS L. , CAPPS W. , SPINNER S.
Published: June 2006

The viscosity and electrical resistance of members of the systems Li2O–B2O3, Na2O–B2O3, and K2O–B2O3 have been measured in the approximate temperature range 600° to 1000°C. The log viscosity isotherms in the range 700° to 800°C. showed a minimum in the low‐alkali region followed by a maximum as the alkali concentration was increased. This behavior could be explained by postulating an equilibrium between two antithetical effects caused by the addition of alkali oxide to B2O3. The log electrical resistance isotherms decreased rapidly with increased alkali content up to about five equivalents of alkali ions per liter and decreased less rapidly in a linear fashion with further increase in alkali ion concentration. The equivalent conductance increased with alkali concentration, indicating behavior rather typical of liquids of low dielectric constant. The rate of increase of equivalent conductance was greater in the concentration region where the viscosity was increasing than where the viscosity was decreasing, thus illustrating that viscosity is not a controlling factor in electrical conduction. A plot of log R vs. log gave straight lines whose slopes decreased with alkali content. The hypothesis that electrical resistance and viscosity of each glass were both related to the concentration of weak bonds in that glass was advanced to account for the constancy of the relation between the temperature coefficients of the two properties.
Thermal Capacity of Vitreous Silica
Authors: SMYTH HAROLD T. , SKOGEN HAVEN S. , HARSELL WILLIAM B.
Published: June 2006

It is assumed that the atoms in vitreous silica can be regarded as independent oscillators. Each silicon atom is taken as having three independent equal frequencies and each oxygen as having two equal transverse frequencies and one different longitudinal frequency. Reasonable values assigned to these frequencies give a calculated thermal‐capacity curve which is a fairly good approximation of the experimental curve except at very high and very low temperatures. These data also throw light on the reason for the very low thermal expansion of vitreous silica.
Uranium Oxide Phase Equilibrium Systems: I, UO2–Al2O3
Authors: LAMBERTSON W. A. , MUELLER M. H.
Published: June 2006

The UO2–Al2O3 phase equilibrium system was found to contain no new compounds or solid solutions. Uranium dioxide melted at 2878°± 22°C. and Al2O3 melted at 2034°± 16°C. The eutectic temperature was approximately 1930°C. There is an indication that two immiscible liquids formed above the eutectic temperature between 53 and 74 mole % Al2O3.
Effect of TiO2, Fe2O3, and Alkali on Mineralogical and Physical Properties of Mullite‐Type and Mullite‐Forming Al2O3‐SiO2 Mixtures: I
Authors: SKINNER KENNETH G. , COOK W. HOWARD , POTTER RALPH A. , PALMOUR HAYNE
Published: June 2006

This report gives the results of the first phase of an investigation to determine the effects of TiO2, Fe2O3, and alkalis on mullite‐forming Al2O3‐SiO2 mixtures. Preliminary tests indicated that the effects of TiO2 might depend on the Al2O3‐SiO2 ratio. Therefore an Al2O3‐SiO2‐TiO2 sub‐system was studied which indicated that 5% TiO2 might be beneficial. Test bars with a composition of 5 TiO2, 65 Al2O3, 30% SiO2 not only had the highest mullitization but also had satisfactory physical properties. A second series of tests was made in which Fe2O3 and/or alkali was substituted for all or part of the 5% TiO2. Fe2O3 and TiO2 reacted similarly in quantities up to 2 or 3%; however, more than 2% alkali was generally harmful. More TiO2 could be tolerated than Fe2O3, especially in the presence of more than 1% alkali. These conclusions are based only on data for sintered materials and may not apply to fused materials.
The Polymorphism of Cordierite
Authors: KARKHANAVALA M. D. , HUMMEL F. A.
Published: June 2006

During the course of a broader investigation on the cordierite‐spodumene join in the system Li2O–MgO–Al2O3–SiO2, a clearer picture of the relationships between the various reported polymorphs of cordierite has been developed. Three forms of cordierite have been recognized.*α‐Cordierite is the stable high‐temperature form commonly found in nature and in ceramic bodies. The other two forms are much less common and can be prepared only under special conditions. μ‐Cordierite, found by Rankin and Merwin, forms metastably by crystallization of glass in air below 900°C. and then reverts somewhat sluggishly to the α form when heated above this temperature. μ‐Cordierite has been found to be structurally analogous to β‐spodumene. Stable β‐cordierite forms hydrothermally below 830°C. from glass or from the two other crystalline forms. The equilibrium inversion temperature of β→α cordierite is given by Yoder as 830°C.
Metal‐Ceramic Interactions: II, Metal‐Oxide Interfacial Reactions at Elevated Temperatures
Authors: ECONOMOS G. , KINGERY W. D.
Published: June 2006

Interfacial reactions of various metals (Be, Mo, Nb, Ni, Si, Ti, and Zr) with dense oxide specimens (Al2O3, BeO, MgO, ThO2, and TiO2) were investigated at temperatures up to 1800°C. The reactions in general occurred in the same order as thermodynamic stabilities indicated. Four general types of behavior were observed. There was little or no reaction at 1400°C., but considerable reaction took place in many systems at 1800°C.
Relation Between Roughness of Interface and Adherence of Porcelain Enamel to Steel
Authors: RICHMOND J. C. , MOORE D. G. , KIRKPATRICK H. B. , HARRISON W. N.
Published: June 2006

Porcelain enamel ground coats were prepared under conditions that gave various degrees of adherence, and adherence and roughness of interface were evaluated. A positive correlation was found between adherence and roughness of interface, and it was concluded that roughness of interface is a necessary, but not a sufficient condition for the development of good adherence between a porcelain enamel ground coat and iron. Most of the roughness that is associated with good adherence apparently develops during the firing process.
Influence of Impurities on Electrical Conductivity of Rutile
Authors: JOHNSON G. H.
Published: June 2006

Electrical conductivity can be produced in rutile (1) by replacing an occasional Ti4+ ion with another cation having a positive charge higher than four or (2) by incorporating small cations, such as the Be2+ ion, into interstitial positions in the crystal lattice. This excess positive charge must be balanced by “available electrons,” which then form a constituent of such an impure rutile crystal. The insulating properties of such a contaminated rutile crystal can be partly restored by incorporating into its lattice cations of a lower valency, such as trivalent aluminum and yttrium. Under these conditions a couple, Nb5+Al3+, takes the place of two Ti4+ ions and the crystal does not need to retain extra electrons that are available for conductivity.
Cellulated Ceramics for the Structural Clay Products Industry
Authors: NICHOLSON C. M. , BOLE G. A.
Published: June 2006

Cellulated clay products suitable for structural uses and having fine, uniform cellulation, low density, high strength, accurate dimensions, large unit size, open or closed cells, and high or low absorption have been developed. Materials, methods of manufacture, and properties of foamclay, a lightweight material for interior applications, are presented together with the results of a pilot‐plant operation. Compositions and firing techniques are given for the manufacture of large firebloated units from buff‐burning fire clays. The firebloated products are characterized by low density and high strength and can be produced with either high or zero absorption. The industrial applications and future possibilities of these products are discussed.
Preparation of Refractories from Uranium Dioxide
Authors: CORWIN R. E. , EYERLY G. B.
Published: June 2006

The preparation of refractories from uranium dioxide is governed by certain properties of the material that require special consideration. Significant among these properties are (1) the oxidation characteristics, which necessitate firing in a hydrogen atmosphere, (2) the nonplastic nature, which presents forming problems, (3) the chemical reactivity, and (4) the radioactivity, which necessitates special precautions in handling to avoid health hazards. Crucibles and shapes are formed both by pressing and by slip casting. Pressing is performed without binders of any kind and therefore entails limitations in die design, close control of water content and pressure, and extreme care in handling the green ware. Slip casting is made possible by leaching the finely ground UO2 in concentrated hydrochloric acid solution, followed by thorough washing to remove the excess acid. A binder to increase dry strength is helpful and may assist in deflocculation. If Carbowax‐4000W is used as a binder, very thin crucibles (1/16 in. thick) can be cast. The slip must be carefully controlled for successful casting and special attention must be given to mold design and casting technique. A molybdenum furnace with a hydrogen atmosphere is used for firing all UO2 refractories. The usual firing temperature is 1750°C. At this temperature shrinkage is approximately 15% and density is more than 80% of the maximum theoretical density. Shrinkage and density increase abruptly at higher temperatures.
Subsolidus Reactions in Oxide Systems in the Presence of Water at High Pressures
Authors: OSBORN E. F.
Published: June 2006

Phase equilibrium studies at subsolidus temperatures, made in the presence of an aqueous phase at high pressures, are briefly reviewed for the systems eucryptite–silica, Al2O3–Ga2O3, MgAl2O4–Al2O3, and TiO2. Low‐temperature equilibrium relations have been largely clarified for the first three systems because of the greatly increased reaction rate in the presence of a fluid phase. For the system TiO2, however, hydrothermal techniques appear to be inadequate for the determination of stability relations. The hydrothermal syntheses of forsterite at 500° to 700°C. from magnesia and silica or from dolomite and silica, and of mullite at 500°C. from clay minerals, are mentioned as reactions of possible industrial significance. A further acceleration of reaction rate at low or moderate temperatures is being achieved by grinding at elevated temperatures and pressures.
Effect of Molten Aluminum on Alumina‐Silica Refractories
Authors: BRONDYKE K. J.
Published: June 2006

All commercial alumina‐silica refractories were found to be wetted and subsequently penetrated on exposure to molten aluminum. Penetration and silicon pickup by the aluminum was independent of porosity, grade of refractory, and source of the refractory material. The rate of penetration was governed by the diffusion of aluminum and silicon. The adherence of build‐up to alumina‐silica refractories is related to the silica content of the refractories.
A High‐Temperature Laboratory Catenary Kiln
Authors: ECONOMOS GEORGE , VINAL FRANCIS E.
Published: June 2006

The catenary curve was analyzed to find the dimensions at which a self‐supporting arch can be obtained. For kiln construction, a height‐to‐base ratio of 1 to 1 was found to be advisable. Detailed construction data are given for a kiln with a 0.5‐cu. ft. chamber. A parallel heating element system with a low‐voltage, high‐ampere power circuit is described and the advantages of the arrangement are noted. Excellent temperature uniformity is reported, and 1400°C. can be attained at a rate of 65°C. per hour with 3‐kw. power input. An itemized cost of construction is also given.