bluuebunny/crossref_metadata_2025 huggingface dataset:
PRELIMINARY STUDY ON PORTIONS OF SYSTEMS Na2O‐CaO‐AI2O3‐Fe2O3 AND Na2O‐CaO‐Fe2O3‐SiO2*
Authors: Eubank W. R. , Bogue R. H.
Published: June 2006

Abstract

Portions of the quaternary system Na2O‐CaO‐Al2O3‐Fe2O3 have been studied by the exploration of (1) the plane CaO‐4CaO.Al2O3°Fe2O3‐(Na2O + 3Al2O3) and (2) planes above the base system CaO.5CaO.3Al2O3–2CaO.Fe2O3 which contain successively increasing amounts of Na2O up to 6%. A portion of the quaternary system Na2O‐CaO‐Fe2O3‐SiO2 has been studied by the exploration of a plane containing 5% of Na2O above the base system CaO‐2CaO.SiO2‐CaO.Fe2O3.

In the pseudosystem CaO‐4CaO.Al2O3.Fe2O3‐(Na2O + 3A12O3) the compound Na2O.‐8CaO.3A12O8 was found to exist as a primary phase, and the area in which the plane cuts the Na2O.8CaO.3A12O3 primary‐phase volume was established. Three points on uni‐variant curves were located. The iron phase (4CaO.A12O3.Fe2O3 solid solution) was observed to exist in a solid‐solution series.

In the system Na2O‐CaO‐5CaO.3Al2O3‐‐2CaO.Fe2O3 it was found that the compound Na2O.8CaO.3Al2O3 appears at an Na2O concentration of 4.2%. As soda, however, is taken into solid solution by other phases, it was not feasible at this time to determine the invariant point for Na2O.8CaO.3A12O3, 3CaO.Al2O3, 5CaO.3A12O3, and 4CaO.Al2O3.‐Fe2Oa solid solution.

In the system Na2O‐CaO‐2CaO.SiO2‐CaO.Fe2O3 no ternary compounds were observed up to the 5% limit of Na2O employed. A soda‐containing phase occurred in solid solution with α‐2CaO.SiO2, which may precipitate on cooling, forming inclusions in the ß‐2CaO.SiO2, or enter into reaction with the glassy phase.
DETERMINATION OF FACTORS AFFECTING SIZE VARIATION IN CLAY PRODUCTS*
Authors: Hursh R. K. , Morgan W. R.
Published: June 2006

Abstract

Factors which cause variations in the finished size of clay products are determined. These are classified in the order of their importance, and limits are established within which the factors must be controlled to reduce these variations to a point which is consistent with the commercial production of modular products.

The factors found to have the greatest effect on the finished size are soaking temperature and soaking time. Those factors having a lesser effect are (1) firing atmosphere, (2) relative amounts of clay mineral and quartz present in the clay in the different parts of the pit, (3) grain size of the clay produced by grinding or weathering, and (4) deairing treatment.
INFLUENCE OF VARIOUS DEAIRING AND COMPRESSED‐AIR TREATMENTS ON WEARING QUALITIES OF MILL BALLS AND MILL‐BRICK LININGS*
Authors: Schurecht H. G.
Published: June 2006

Abstract

It was found that the wearing qualities of mill balls and mill‐brick linings may be governed to a large extent by deairing and compressed‐air treatments. It appears that the auger destroys some of the benefits gained by deairing, while the piston‐extrusion machine retains many of these benefits. Deairing the freshly pressed mill balls was found to be beneficial if the blanks were extruded from a deairing machine, but was found to be harmful if the blanks were extruded without deairing.

On the other hand, subjecting the mill balls which have been deaired after forming to a compressed‐air treatment improved the mill balls made of blanks extruded without deairing, but proved to be somewhat harmful to mill balls made of blanks extruded from a deairing machine.
ELECTRICALLY CONDUCTING GLASSES*
Authors: Green Robert L. , Blodgett Katharine B.
Published: June 2006

Abstract

Glasses containing lead, bismuth, or antimony oxides or combinations of these become conducting after several hours’ reduction in hydrogen. The electronic surface conductivity is both stable and reproducible. The magnitude of the conductivity depends on the nature and amounts of the reducible oxides, the temperatures at which reduction is carried out, and the electrical influence of the nonreduced portions of the glasses.
CHANGES IN THE INDICES OF REFRACTION AND LIQUIDUS OF A BARIUM CROWN GLASS PRODUCED BY THE PARTIAL SUBSTITUTION OF SOME OXIDES*
Authors: Hamilton Edgar H. , Grauer Oscar H. , Zabawsky Zeno , Hahnbr C. H.
Published: June 2006

Abstract

Optical glasses with high indices of refraction and Abbe values are very desirable for wide angle lenses. In order to determine the range of compositions in which glasses of this type could be produced, oxides of lithium, beryllium, calcium, boron, lanthanum, or thorium were substituted for barium oxide or silica in a three‐or‐four component base glass. Substitutions were made on a mole‐for‐mole basis. The indices of refraction for the C, D, F, and G lines and the liquidus were determined for each glass. Experimental glasses with indices of refraction (nD) and Abbe values from 1.600 to 1.714 and 62.2 to 52.7, respectively, were made in small platinum crucibles.
EFFECT OF THE SULFATE ION ON THE PLASTICITY OF BRICK CLAYS*
Authors: Johnson A. L. , Hughes George B.
Published: June 2006

Abstract

Two red‐firing Iowa brick clays were analyzed for sulfate (SO4−) content by a method suitable for plant‐control tests. From this datum the amount of barium carbonate required to react with this ion can be calculated. Plasticity measurements on (1) samples treated with the amount of barium carbonate indicated by SO4− analysis, (2) untreated samples, and (3) samples treated with normal plant additions show significant differences in this property. These differences can be explained using the modern concepts of the factors which influence the zeta potential.
DETERMINATION OF IRON IN GLASS SAND*
Authors: Diamond J. J.
Published: June 2006

Abstract

The 0‐phenanthroline method for the colorimetric determination of iron has been adapted to the analysis of glass sand. The sample taken for analysis was decomposed by treatment with HF and H2SO4, followed by fusions of any insoluble material with Na2CO3 and finally with K2S2O7. An aliquot was then adjusted to the proper pH by a simple procedure, the iron reduced by hydroxylamine hydrochloride, the 0‐phenanthroline complex formed, and the transmittancy of the solution measured spectrophotometrically. The method is simple and rapid, and compares favorably in precision and accuracy with other available methods.
EFFECTS OF VARIOUS CLAYS USED IN MILL ADDITIONS ON PROPERTIES OF A TITANIA‐OPACIFIED ENAMEL*
Authors: Marbaker Edward E. , Saunders Hollis S. , Baumer Leon N.
Published: June 2006

Abstract

In the course of investigations made in connection with the development of titania‐opacified enamels, it was observed that color, reflectance, and acid resistance were influenced by the clay used in the mill additions. In a subsequent search for a clay which would produce the best over‐all enamel properties, a study of the effects of twenty clays of different types was made under standardized conditions of milling, spraying, and firing. Coatings sprayed at 30 gm. per sq. ft. were examined for bisque strength, brushing behavior, and tearing. After firing for 3 minutes at 1540°F., and at 1640°F., the reflectance, color, gloss, and acid resistance of the enamels were observed. It has been concluded that the success or failure of an enamel is determined to an important degree by the clay used in the mill addition.
Synthetic Sapphirine and Its Stability Relations in the System MgO‐Al2O3‐SiO2
Authors: FOSTER WILFRID R.
Published: June 2006

A compound corresponding in optical properties and in X‐ray powder pattern with the natural mineral sapphirine has been synthesized by repeated sintering of the constituent oxides at atmospheric pressure. The most probable formula for this synthetic compound is 4MgO.‐5Al2O3· 2SiO2. An unidentified crystalline phase previously noted in certain magnesia‐aluminasilica porcelains has been shown to be identical with this synthetic sapphirine. There is reason to believe that sapphirine possesses a small field of primary crystallization on the liquidus surface of the ternary system MgO‐Al2O3‐SiO2. Some revision of the earlier work on this system therefore appears to be necessary. Experiments designed to prove the existence of sapphirine as a synthetic mineral, and to determine its thermal behavior and its stability relations with other crystalline phases in the ternary system, have been carried out. The results indicate that synthetic sapphirine melts incongruently at or near 1475 °C. to yield spinel and liquid, and that immediately below that temperature sapphirine is compatible with cordierite, spinel, and mullite, and at still lower temperatures with corundum also. On the basis of these results a revision of the equilibrium diagram for the system MgO‐Al2O3‐SiO2 has been made.
ThermaIly Resistant Whiteware
Authors: SMOKE E. J.
Published: June 2006

Thermal endurance in the field zircon‐calcium zirconium silicate‐clay was evaluated together with those physical properties that should contribute most to this characteristic. The coefficient of thermal expansion was similar throughout the field, resulting in an area of high thermal endurance which coincided quite closely with that of high transverse strength. The best compositions did not fail until the 500 °F. quenching cycle (one cycle at each temperature) and withstood 30 cycles from 400°F. Petrographic analysis revealed that good thermal endurance could be attained over a wide range of compositions.
Investigation of Various Properties of Zircon and of Stabilized Zirconia at Elevated Temperatures, I–III
Authors: CURTIS CARL E. , LAURIE DOMINIC
Published: June 2006

The reactions of zircon and of stabilized zirconia in contact with each of fourteen commercial refractories at temperatures ranging from 2400° to 3600°F. were studied. A heating schedule of 4 hours with 1 hour at maximum temperature was used, and the safe upper limits to avoid reaction between both zirconia and zircon and the various refractories were established. To correlate this information with commercial high‐temperature furnace installations, tests were made to determine the heat‐transfer rates through stabilized‐zirconia brick of both the dense and the insulating types. The hot‐load resistance of the commercial refractories was determined, using a small oxyacetylene‐fired furnace in which 1‐in.‐cube samples were heated from all sides under a 25–1b. load. Studies were made of the effect on hot‐load resistance of variations in (a) load, (b) holding temperature, and (c) dimensions of the test piece. Other tests were designed to demonstrate the large increase in hot‐load resistance obtained when the specimen was heated from one side only, as in a furnace wall.
Systematic Study of Simple Titania‐Bearing Porcelain Enamels
Authors: FRIEDBERG A. L. , PETERSEN F. A.
Published: June 2006

An extensive composition study of titania enamels and their properties is described. The compositions investigated contained only six constituents, namely, Na2O, K2O, SiO2, B2O3, TiO2, and F2. Systematically and over a wide range, the contents of SiO2, B2O3, TiO2, and alkali were varied. One hundred enamels in all were made and the resulting properties were determined. Properties noted included flow, expansion, color, percentage of anatase, gloss, reflectance, and acid resistance at various firing temperatures.

Enamel Y12, representing a small area in this large composition field, exhibited the properties requisite for a good hollow–ware white cover–coat enamel. Compared with previously studied titania enamels, this enamel is “softer”; i.e., it fires at lower temperatures, has the desired higher flow and expansion, yet still possesses the required properties of color stability, reflectance, gloss, acid resistance, and workability.
Design of a High‐Temperature Resistance Furnace
Authors: McRITCHIE F. H. , AULT N. N.
Published: June 2006

An electric resistance furnace is described that is capable of operating at temperatures up to 3770 °F. (2075°C.) in vucuo or in hydrogen or noble‐gas atmospheres. Problems of outgassing and atmosphere contamination by furnace materials are largely circumvented by eliminating insulation.
A Thickness Gauge for Ceramic Coatings
Authors: GORDON CHARLES C. , RICHMOND JOSEPH C.
Published: June 2006

An instrument has been developed for the purpose of measuring the thickness of protective coatings of ceramic materials applied on nonmagnetic metal bases. This instrument provides a nondestructive method of measurement and can be used on metallic backings having a wide range of electrical conductivities. Also, the thickness measurement refers to a restricted area and is, therefore, applicable to curved surfaces. Although this instrument was developed primarily for the measurement of the thickness of ceramic coatings on turbine blades and other high‐temperature parts of aircraft power plants, it should be generally useful in thickness measurements of paint, plastic, and other nonconducting films.
The Influence of Base Composition and of Minor Constituents on the Coloration of Carbon‐Sulfur Amber Glasses
Authors: LYLE A. K.
Published: June 2006

Compositions of commercial amber glasses are reviewed briefly. Experimental results for variations in coloring ingredients are shown to affect not only the color, but also the fining. One of the major factors in determining color is the base composition which, contrary to previous reports, is shown to require high silica and low alkali contents for greatest intensity and stability of color. Other results show that color is intensified by the presence of fluorides and that added iron is unnecessary to the development of strong stable colors.
Design and Performance of Electric Furnaces with Oxide Resistors
Authors: DAVENPORT W. H. , KISTLER S. S. , WHEILDON W. M. , WHITTEMORE O. J.
Published: June 2006

Oxide heating elements for electric furnaces, conditions for electrical stability within an element or a group of elements, and end connection problems are discussed. A description is given of a resistance furnace which will operate at 1600°C. in air, a resistance furnace for 2200°C. in hydrogen, and an induction furnace for 2200°C. in air.
Note on Beta‐Alumina Occurrence in Glass Tank Refractories
Authors: BOR LESLIE
Published: June 2006

The occurrence of β‐alumina in glass tank refractories is discussed, and its identifying features are described.
A Note on the Determination of Sodium and Potassium in Clays
Authors: OSTHAUS B. B.
Published: June 2006

By combining existing procedures, direct determination of sodium and potassium can be accomplished without resort to a carbonate‐chloride fusion. Analytical results are reported for the National Bureau of Standards clay sample No. 98.
III, Phosphate Adsorption by Clay and Bond Migration
Authors: KINGERY WILLIAM DAVID
Published: June 2006

The adsorption of monoaluminum phosphate on Florida plastic kaolin was found to be 13.3 m.e. per 100 gm., whereas North Carolina kaolin adsorbed 9.6 m.e. per 100 gm. The effects of time, solution concentration, and pH were slight. Ball milling of North Carolina kaolin for 98 hours reduced the particle size of the clay considerably and increased the adsorption to 92.5 m.e. per 100 gm. A logarithmic plot of adsorption of monodisperse fractions of the ground material vs. equivalent spherical diameter gave a straight line, indicating the phenomenon to be surface adsorption. The ground material had a higher adsorption capacity than unground material of the same particle size. The rate of drying and of migration of sodium chloride and monoaluminum phosphate with unground clay and clay ground 98 hours was determined. The rate of drying of sodium chloride solutions depended on the salt content and was similar for ground and unground materials, as was the final salt distribution. Ground monoaluminum phosphate having a high adsorption capacity showed almost no salt migration, a rate of drying like that of water, and no surface deposition of monoaluminum phosphate.
Refractory Castables: Preparation and Some Properties
Authors: HEINDL R. A. , POST Z. A.
Published: June 2006

Refractory castables in this investigation contained (a) aggregate made from unused high‐duty fire‐clay brick or calcined Kentucky flint clay and (b) domestic or imported high‐alumina hydraulic cement. The bulk densities were determined for different mixtures of grog passing through (a) a 3/8 in. sieve and retained on a No. 10 sieve, (b) a No. 10 on a No. 40, and (c) a No. 40 (including fines). The bulk densities of a large number of such mixtures were plotted on triaxial diagrams and contour lines were drawn. One each of the more dense combinations containing fire‐clay brick grog and calcined flint‐clay grog was selected for making tests of batches containing from 10 to 30% of hydraulic cement. The tests indicated the effect on strength of (1) the curing treatment to which the specimens had been subjected, (2) the length of time the mixed batches remained unmolded, and (3) the varying cement: water ratio. The pyrometric cone equivalents of batches containing from 5 to 30% of cement, in increments of 5%, were determined.
Corrosion Resistance of Pure Alumina as a Glass Refractory
Authors: DAY FRANK , AMBUOSONE J. P.
Published: June 2006

Small corrosion test samples were cut from nonporous, single‐crystal, gem‐and‐bearing‐type sapphire boules. These, along with similar samples of “Corhart ZAC”* refractory, were placed in contact with a common lime glass for various lengths of time at temperatures between 1400° and 1550°C. The results of metal‐line cut measurements show that, at a given temperature, the corrosion resistance of a pure, nonporous single crystal of alumina is less than that for a commercially available refractory composition.
Variation, with Temperature, of the Cracking Velocity of Glass
Authors: DIMMICK H. M. , McCORMICK J. M.
Published: June 2006

The limiting velocity of fracture for a soda‐lime glass was measured as a function of temperature over the range of 80° and 475°K. The value of the fracture velocity was obtained by electronically measuring the time necessary for the crack to travel between two platinum lines fired into the surface of the glass specimen. The value of the fracture velocity for this glass was found to be 1485 m. per second at 300°K. with the velocity decreasing slightly with increasing temperature over the range studied. The results indicate a temperature coefficient on the order of –0.15 m. per second per °K.
Fundamental Study of Clay: XI, Note on the Effect of Fluoride Ions on a Clay Suspension
Authors: KINGERY WILLIAM DAVID
Published: June 2006

The effect of fluoride ions on the viscosity, yield point, pH, and conductivity of hydrogen‐clay slips and a calcium‐clay slip is shown. These data indicate that fluoride ions deflocculate hydrogen‐clay slips by the same mechanism as hydroxyl ions because these ions are isoelectric and approximately the same size. The data tend to confirm the electrocratic theory of deflocculation. The fluoride ion was not effective for deflocculating the calcium‐clay slip.
The Location of Sodium by Nuclear Activation in Glass‐Corroded Tank Block Refractories
Authors: LAING K. M. , EMHISER D. E. , FITZGERALD J. V. , JONES R. E.
Published: June 2006

The location and concentration of sodium in refractory samples tested in molten plate glass was shown by two nuclear physics techniques, activation and isotope tracing. Detection of the radioactive atoms was accomplished by photographic plates (autoradiography). Corrosion by molten glass was carried out either in a small glassmelting tank or in hot glass in a platinum crucible. Clay‐grog and fused‐cast refractories were tested. The results were anomalous, but illuminating.
Some Semiempirical Methods for Estimating the Entropies of Oxides, Silicates, and the Prediction of Reaction Equilibria and Yields
Authors: KNAPP W. J. , VAN VORST W. D.
Published: June 2006

Several methods are reviewed for computing the entropies of crystalline inorganic oxides, silicates, and titanates. A method relating entropies with molecular weights is used for oxides. The entropies of silicates and titanates may be estimated with the sums of the entropies of oxides with which they may be considered to be formed. Calculations are suggested to obtain free energy changes for reactions in systems of ceramic materials. Free energy calculations will allow for the prediction of reaction equilibria and yields. An example is given for the reaction at 1100°C. between calcia and silica to form calcium silicate.
Mineral and Chemical Changes in Periclase Brick Under Conditions of Steel Plant Operation
Authors: WELLS R. G. , VAN VLACK L. H.
Published: June 2006

Periclase refractories develop definite zones while in service in steel plant furnaces. These zones represent a concentration gradient through the brick that results from (1) the thermal gradient across the brick and (2) the absorption of material from the furnace atmosphere. A silicate liquid, which forms a network nearly surrounding the periclase grains, is concentrated chiefly in a zone of about 1500°C. This liquid probably weakens the structure of the brick sufficiently to permit cracks to form under the stresses of furnace operation. These in turn lead to major refractory losses by spalling.
Thermal Expansion of Some Glasses in the System MgO–Al2O3–SiO2
Authors: HUMMEL F. A. , REID H. W.
Published: June 2006

The thermal expansion coefficients of five magnesia‐alumina‐silica glasses were measured in the range 25° to 700°C. by the use of the interferometer. The glasses included the 1345° and 1360°C. eutectic compositions and three compositions having molecular ratios of 1 : 1 :4, 1 : 1 :6, and 1 : 1 : 10. The relation of the data to other glasses, porcelain glaze formulation, and the firing of cordierite ceramics is discussed.
Reaction of Vaporized Sodium Sulfate with Aluminous Refractories
Authors: GOW KENELM V.
Published: June 2006

A method was devised and tested whereby the action of an alkali salt, in the vapor or in the liquid state, on refractory materials may be studied under controlled conditions of temperature and pressure. Using Na2SO4, the progress of reaction was followed by (1) change of weight, (2) determination of SO3 by precipitation, and (3) determination of Na2O by flame photometer. The materials studied were a commercial‐grade high‐alumina brick (88% Al2, 11 % SiO2) * and fused crystalline alumina (99.5% Al2O3).

The dissociation of sodium sulfate, reacting in contact with high‐alumina refractory materials, is speeded more by the presence of SiO2, probably as the compound mullite, than by crystalline alpha‐alumina. The ultimate product in the commercial brick is probably nephelite, NaAl‐SiO4; in the alumina, sodium alumina, NaAlO4.

Exposure at 1200°C. in a vacuum of 150 μ of mercury approximately doubles the rate of deposition of sodium sulfate on the brick studied and adds one‐third to the rate on fused alumina, as compared with the rate in air at atmospheric pressure.
Colorimetry of Glazes
Authors: O'BRIEN PHILIP F.
Published: June 2006

Some color characteristics of ceramic glazes that are important in industrial design and specification are described in terms of the fundamental parameters of colorimetry. Algebraic expressions are developed to relate the spectral reflectance of a specularly transmitting glaze on an opaque bisque with the glaze thickness, interfacial reflectance, absorption coefficient, and colorant concentration. These expressions are shown to describe accurately the spectral reflectance of some test tile. Changes in dominant wave length, purity, and luminous reflectance are considered with glaze thickness as the independent variable. The dichroic effect associated with glaze‐thickness difference in a purple tile is illustrated. A relationship between glaze‐thickness difference and allowable color tolerance is outlined.
Radiation‐Absorbing Glasses
Authors: BREWSTER GORDON F. , KREIDL NORBERT J.
Published: June 2006

Glasses of high X‐ray, thermal‐neutron, or combined X‐ray and thermal‐neutron absorptivity and satisfactory technological properties were developed: lead tantalum (niobium, thorium) borate, phosphate, and germaniate glasses for X rays, cadmium‐titanium‐zirconium borates for thermal neutrons, and lead cadmium borates for their combination. These glasses were compared with known absorbers.
Preliminary Study of the Compressive Stress Relief of Titania‐Opacified Cover‐Coat Enamels
Authors: BOWMAN D. C. , SHARON A. V.
Published: June 2006

Titania‐opacified cover‐coat enamels applied over ground‐coated sheet metal are subject to varying amounts of compressive stress. The initial stress as well as the stress after annealing at 550°F. of eight titania‐opacified enamels of different fusibilities was investigated by means of expansiometer rings. A general relationship between compressive stress relief due to annealing and fusibility of the enamels was established.
Lattice Constants and Dielectric Properties of Barium Titanate—Barium Stannate—Strontium Titanate Bodies
Authors: DUNGAN R. H. , KANE D. F. , BICKFORD L. R.
Published: June 2006

Lattice constants and temperatures corresponding to maximum dielectric permittivity were investigated for compositions in the barium titanate‐rich portion of the system barium titanate–barium stannate–strontium titanate. Substitution of tin for titanium increases the lattice constant at room temperature, and substitution of strontium for barium decreases this parameter. Both types of substitution decrease the Curie temperature; tin is about twice as effective as strontium in this regard. Properties of bodies containing both tin and strontium are intermediate between those of bodies containing either alone.
A Study of Gases in Porcelain Enameling
Authors: CHU P. K. , KEELER J. H. , DAVIS H. M.
Published: June 2006

Gas evolved from all delayed enamel defects was found to be substantially pure hydrogen. By the method of microscopic‐gas‐bubble analysis, gas from individual reboiling blisters in ground‐coat enamel was shown to contain more than 84% of hydrogen. The water‐iron reaction is an ever present source of hydrogen in enameling. The water is supplied by the dried enamel slip, not only as structural water in clay, but also as part of the glass structure of the frit. Clays containing high percentages of structural water and having high decomposition temperatures tend to increase the production of gas‐formed defects. Enclosed‐system experiments revealed that hydrogen is absorbed by steel‐enamel interfacial material at 500°C. Similarly an enamel containing 3.0% of Sb2O3 will absorb hydrogen very readily at 500° to 700°C. A study was made of gas evolution in the heating of enamel slip or frit separately or with steel. Heating the dried frit with steel produced hydrogen. The roles of water and hydrogen in the enameling process and the mechanism of the formation of reboiling blisters and delayed defects are discussed.
Dielectric Bodies in the Quaternary System BaTiO3–BaSnO3–SrSnO3–CaSnO3
Authors: COFFEEN WILLIAM W.
Published: June 2006

Dense bodies were prepared of compositions in the quaternary system BaTiO3–BaSnO3–SrSnO3–CaSnO3 containing from 3 to 60 mole % stannate. The general effect of the stannate addition to barium titanate was to decrease the Curie temperature and broaden the peak. On a molar basis the three stannates were approximately equivalent in their effect on the dielectric properties of barium titanate, although the rate of shift of the Curie temperature was slightly greater when SrSnO3 was used. Bodies containing calcium or strontium stannate had lower power factors than those containing barium stannate. Bodies compounded with calcium stannate matured most readily and at lower temperatures. Bodies having dielectric constants (K) of 2300 to 2800 at 1 kc. with low positive temperature coefficients up to about 55°C. were obtained with a 3 mole % addition of stannate. Bodies with minimum K's of 3000 to 4000 at 1 kc. over the range 25° to 85°C. were obtained from BaTiO3 with an addition of about 6 mole % BaSnO3, SrSnO3, or CaSnO3. Bodies with negative temperature coefficients of K ranging from about 13,000 to about 1000 p.p.m. per °C. were obtained with stannate additions of from 10 to 60 mole %.
Some Properties of the System Na2O‐NaF‐B2O2‐H2O
Authors: KING BURNHAM W.
Published: June 2006

It was first shown that the enamel slips which have the best suspnding characteristics contain equal amounts of Na2O and B2O3 and at least a moderate amount of NaF. The solubilities of mixtures of Na2O, NaF, and B2O3 were then investigated. The pH of these solutions and the primary crystalline phases separating on evaporation also were determined. The solubility data obtained at room temperature were summarized. When the solutions were evaporated, NaF was the first crystalline phase to separate from a large proportion of the mixtures investigated. It was concluded that the desirable handling characteristics of enamels whose mill liquors contain the proper proportion of Na2O, NaF, and B2O3 are not due to the formation of complex salts but to the following combination of properties: (1) the presence of salts with a moderate solubility which changes very slightly with temperature, (2) a moderate pH of about 10 in a probably well‐buffered solution, (3) a relatively stable crystalline material, NaF, as a primary phase, and (4) a secondary phase which crystallizes slowly with relatively little shrinkage.
Effects of Zirconium‐Type Opacifiers on Properties of Glazes
Authors: JACOBS C. W. F. , BALDWIN W. J.
Published: June 2006

The use of various zirconium‐type opacifiers such as zircon, zirconia, and the alkaline‐earth silicates of zirconium in fritted and raw glazes maturing in the range cones 06 to 04 and cones 9 to 11, respectively, and the properties of the resulting slips and fired glazes were investigated. Substitution of the various opacifiers was in each instance based on the molecular glaze composition. In the fritted glazes maturing at cones 06 to 04 where the use of all types of zirconium opacifiers was not possible without altering the molecular composition, optimum properties were obtained with zircon. In the raw type of glaze maturing at cones 9 to 11, in which a greater variety of opacifier substitutions could be made, combinations of the alkaline‐earth silicates of zirconium as opacifiers produced a marked improvement in slip properties and a definite reduction in opacifier segregation compared with glazes opacified with zircon or with zirconia. Use of the alkaline‐earth silicates of zirconium did not impair other fired properties such as opacity, gloss, texture, and finish.
Shrinkage of High‐Calcium Limestones During Burning
Authors: MURRAY JAMES A. , FISCHER HERMAN C. , ROLNICK LEONARD S.
Published: June 2006

The shrinkage characteristics of forty‐three commercial high‐calcium limestones, calcined at four different temperatures above the dissociation temperature, were studied by means of bulk‐density measurements of the stones and their respective calcines. Chemical, spectrographic, and petrographic analyses could not be correlated with the shrinkage data
Liquidus Relationships on 10% MgO Plane of the System Lime‐Magnesia‐Alumina‐Silica
Authors: PRINCE A. T.
Published: June 2006

The system CaO‐MgO‐Al2O3‐SiO2 is well known for its importance in many fields of ceramic technology, especially in the field of industrial refractories. The present study, although providing additional data on the liquid phases in basic refractory materials, was undertaken primarily to determine the composition‐melting‐ point behavior of iron blast‐furnace slags. About 95% of the composition of blast‐furnace slags generally can be expressed in terms of CaO, MgO, Al2O3, and SO2, the additional constituents being FeO, MnO, and S. The MgO content of these slags depends on the type of “stone” used as a flux, which may be essentially pure limestone, dolomitic limestone, or a mixture of limestone and dolomite as determined by economic factors related to sources of raw materials. The amount of MgO usually varies between 2 and 10% in the final slag, and it is often important to know the effect on the melting point of a substitution of MgO for CaO. In the present study one hundred and two glass compositions were prepared for liquidus and in some cases secondary‐phase temperature determinations by the quenching method. The investigation was confined chiefly to the central part of the plane adjacent to the lime‐silica‐magnesia face of the tetrahedron. Primary fields of s'lica, diopside, anorthite, pseudowollastonite, cordierite, melilite, spinel, mullite, merwinite, dicalcium silicate, periclase, and corundum were encountered in the course of the work. Liquidus temperatures ranged from a minimum of 1230°C. at the diopside‐anorthite‐tridymite intersection to a maximum of about 1650°C. in the dicalcium silicate field, which was the upper safe limit for the equipment. Petrographic and X‐ray diffraction methods were used to identify phases.
Adaptation of Replica Technique to Measurement of Surface Durability of Glass
Authors: SIMPSON H. E.
Published: June 2006

A replica technique was developed for reproducing the corroded surface of glass containers. Before this development a wide variety of techniques had been studied which involved the use of various sheet plastics, such as ethyl cellulose, and various solvents. Most of the methods tried were of little value for curved surfaces because of the difficulties in pressing the plastic sheet uniformly upon the irregular contour of the bottle glass sample. A liquid plastic composed of Vinylite dissolved in methyl isobutyl ketone or acetone gave encouraging results when it was properly applied and dried. The previously weathered samples of bottle glasses were dipped in the plastic solution; after careful drying under controlled conditions, the plastic film was stripped from the surface to give an accurate reproduction of the corroded glass surface. The degree of surface deterioration, as shown by the replica, was then determined with a photoelectric haze meter. Some typical results taken from a study of various container glasses indicated that, as a rule, the inside of the container deteriorated; more rapidly than the outside. The pattern of corrosion on the outside of the container was quite irregular and was distinguished by long flowing lines, such as feeder marks, cutter marks, and mold marks. The inside of the container showed considerably fewer irregularities. Differences were found in the per cent haze vs. time curves for container glasses of varying composition. It was shown that these differences were generally associated with changes in the alumina and magnesia content of the glass.
Influence of Particle‐Size Distribution on the Properties of Nepheline Syenite
Authors: KOENIG C. J.
Published: June 2006

Samples of nepheline syenite prepared by conventional and by fluid‐energy reduction methods were studied to determine (1) their fundamental properties and (2) the characteristics they impart to vitreous bodies. Fluid‐energy grinding methods make it possible to obtain materials which pass a 325‐mesh sieve and yet do not have excessive amounts of extreme fines. The absence of large flux particles is conducive to a uniform distribution of the resultant glassy phase which permits a closer approach to equilibrium conditions and improves the physical properties of whiteware bodies.
High‐Temperature Centrifuge for Separation of the Liquid Phase from Refractories: I, Background Studies
Authors: BIRCH RAYMOND E.
Published: June 2006

Evidence for the migration of the liquid phase in refractories is reviewed, and consideration is given to means of separating the liquid from refractory specimens to allow its study. Methods include absorption by porous media and gravity flow into platinum crucibles (the latter unworkable). Centrifuging at high temperatures is judged to be the most practical, and room‐temperature experiments are described which show that liquid (glycerine) of 1000‐centipoise viscosity can be removed by centrifuging.
An Automatically Recording Thermal‐Expansion Apparatus
Authors: KELLY HAL J. , HARRIS HENRY M.
Published: June 2006

An automatic thermal‐expansion apparatus is described in which the device for sensing sample dilation is a linear variable differential transformer. The equipment plots temperature vs. expansion using a two‐function recording potentiometer. The linear variable transformer was chosen because of insensitivity to thermal changes and to horizontal misalignment, flexibility of range and sensitivity, and small size. Performance data are presented for a number of tests and the advantages and disadvantages of the equipment are discussed. The electrical circuit necessary for adapting the sensing device to this particular use is also described.
Determination of 1600° and 1700°C. Liquidus Lines in CaO‐2Al2O3 and AI2O3 Stability Fields of the System CaO—Al2O3—SiO2
Authors: LANGENBERG FREDERICK C. , CHIPMAN JOHN
Published: June 2006

The 1600° and 1700°C. liquidus lines in the CaO·2Al2O3 and A12O3 stability fields of the system CaO‐Al2O3‐SiO2 are determined from the chemical analyses of saturated slags at these temperatures.
Temperature Inversions of Anhydrous Gallium Orthophosphate
Authors: PERLOFF ALVIN
Published: June 2006

Crystalline GaPO4 was prepared in a hydrothermal bomb at 200° to 300°C. It was found to be isostructural with the berlinite form of AlP04. Thermal analysis and high‐temperature X‐ray techniques were utilized to show that the analogy extends to some of the polymorphic forms of AlPO4 as well. Three forms of GaPO4, corresponding to the berlinite, high‐cristobalite, and low‐cristobalite forms of the A1PO4 system, were observed. No evidence was found to indicate the existence of a tridymite form.
Cermets: III, Modes of Fracture and Slip in Cemented Carbides
Authors: PARIKH N. M.
Published: June 2006

The modes of fracture and slip in cemented carbides were observed. Fracture and slip patterns in cemented carbides were found to vary with the microstructures which in turn were determined by the relative surface energies of various phases. The influence of particle size and metal binder content in cemented Tic and WC was also investigated. The fracture and slip in these systems are discussed in terms of the role of the metal film surrounding the carbide grains.
Mathematical Treatment of Multicomponent Systems
Authors: HEATH D. L.
Published: June 2006

Systems of five or more components cannot be represented in three‐dimensional space. In working with these multicomponent systems, a method must be devised where it is not necessary to visualize the system. A general equation for a system of any number of components is presented. The derivation of the constants by the use of a unity coefficient is demonstrated for hypothetical and for actual systems. Relationships in the quinary system Na2O–Fe2O3–Al2O3–SO2–CaO are derived and the transformation equations are discussed.
Viscous Flow in Glass‐to‐Metal Seals
Authors: HAGY H. E. , RITLAND H. N.
Published: June 2006

Birefringence measurements were made on glass‐to‐metal seals with simple geometries during cooling at various rates. Thermal contraction data were also obtained on the metal and on the glass while cooling at the same rates. Using these data, the viscosity of the glass during cooling at a constant rate was calculated. The viscosity deviates markedly from the equilibrium curve and is a function of cooling rate in this temperature region. Viscous flow in the seal is measurable as much as 125°C. below the strain point.
Effect of Stress and Temperature During Forming on Strength of Glass
Authors: LYNCH E. D. , TOOLEY F. V.
Published: June 2006

The effect of mechanical stress during the drawing process on the strength obtained was determined for large‐diameter fibers of soda‐lime‐silica glass. Fibers were formed by down‐drawing cane at a constant rate, using loads of from 100 to 8000 gm. Tensile strength was determined by transverse loading on annealed specimens. The results showed that the variation of temperature and load during forming increased the strength of the drawn fiber as much as 62%. The tendency toward increased strength persisted, but to a lesser extent, after the surface of the fibers was abraded.
Stress Measurement in Cylindrical Vessels
Authors: RITLAND H. N.
Published: June 2006

An analysis is presented of the birefringence patterns observed in the walls of cylindrical glass objects when viewed tangentially in a matching index fluid. The patterns to be expected from a combination of parabolic and bending stresses, resulting from asymmetric cooling, are calculated. Experimentally measured patterns are shown to illustrate the theory. A simple method is presented whereby the stresses at the outside and inside surfaces of tempered ware can be calculated from the observed pattern.
Role of Cuspidine (3CaO.2SiO2.CaF2) in the System CaO–SiO2–CaF2
Authors: BRlSl CESARE
Published: June 2006

Cuspidine is a well‐defined ternary compound with a stability field in the subsystem CaF2–CaSiO3–Ca2SiO4. Cuspidine is easily formed by solid‐state reactions in the subsystem mentioned and is stable above its apparently congruent fusion point if heated in welded platinum containers. Above 1450° decomposition and the formation of a mixture of CaF2 and Ca2SiO4 is observed. Cuspidine also is easily formed by secondary reactions in solid mixtures of the subsystem CaF2–CaSiO3 and in ternary mixtures of these with free SiO2 if heated in open crucibles. The existence of double compounds of CaF2 and CaSiO3 is not confirmed.
Magnetic and Magnetostrictive Properties of Magnesium‐Nickel Ferrites
Authors: HOFFMANN PAUL O.
Published: June 2006

The purpose of this study was to determine whether or not the magnetic and magnetostrictive properties of mixed Ni‐Mg ferrites having various compositions were superior to those of a simple Ni ferrite. The preparation of the ferrites and the test methods are described briefly. The properties tested were Young's modulus, the remanence, the coercivity, the reversible permeability, the static magnetostriction, the electromechanical coupling coefficient, and the dynamic magnetostrictive constant. The results of the tests showed that the Ni ferrite was superior to the Ni‐Mg ferrites as far as magnetic and magnetostrictive properties were concerned.
Dielectric Loss and the States of Glass
Authors: RINEHART D. W.
Published: June 2006

Specimens of commercial plate glass were compacted at 900°F. and cooled slowly to room temperature. Power loss was determined as the specimens were reheated and quenched from various temperatures within the range 200° to 1200°F. Irreversible increases in tan δ were found to occur at quenching temperatures below the transformation range as well as within it. The increases below the transformation range are considered to result from changes in the Na + ion distribution, established during cooling, among the interstitial holes. As shown by density measurements, the increases within the transformation range are associated with configurational changes in the basic silica network. A glass property that depends on the mobility of a constituent ion is determined by at least two states: (1) a configurational state of the silica network and (2) a distribution state of the mobile ion. The extent of compaction is clearly indicated in a family of curves of tan δ vs. quenching temperature, with compacting time as a parameter.
Grain Growth in Nickel Ferrites
Authors: LEVESQUE PASCAL , GERLACH LAWRENCE , ZNEIMER J. E.
Published: June 2006

A discussion of continuous and discontinuous grain growth in nickel ferrites is presented. Experimental evidence indicates that the presence of polyphase material is favored by excess nickel oxide and that discontinuous grain growth can be accounted for by excess iron oxide. Quantitative measurements of isothermal grain‐growth rates in stoichiometric nickel ferrite yielded an energy of activation of 90 kcal. per mole for the process.
Volatility Studies of Lead Silicate Melts
Authors: HALLSE ROBERT L. , COOK RALPH L.
Published: June 2006

The volatility of various lead silicate melts was determined by measuring the loss in weight at various temperatures from 800° to 1300° C. Platinum crucibles containing the melts were Suspended from an analytical balance into a vertical Global furnace. The crucible studies showed that the loss of lead oxide from melts could be decreased by as much as 80% when lead oxide was combined with silica in monosilicate melts and by as much as 95% when combined with silica in bisilicate melts. Comparative trials on raw lead glazes showed that most of the volatilization occurred in the early stages of glaze melting.
Role of Structural Defects in the Sintering of Alumina and Magnesia
Authors: JONES JOHN T. , MAITRA PRANAB K. , CUTLER IVAN B.
Published: June 2006

Alumina and magnesia compositions containing additions of titanium, chromium, manganese, iron, and zirconium oxides were sintered in atmospheres of oxygen, nitrogen, and hydrogen. Diffusion promoted by lattice defects was observed by measurements of bulk density. Color, atmosphere, and X‐ray diffraction indicated the nature of the structural defects resulting in increased rates of material transport.
Theory of Ion Exchange and Development of Charge in Kaolinite‐Water Systems
Authors: LAWRENCE W. G.
Published: June 2006

Crystal‐chemical concepts applied to cation adsorption on kaolinite crystals in a water medium permit the calculation of bond energies. These values place the cations in the proper sequence of replacing power. Comparison of bond energies with thermal energy makes possible the calculation of charge on the particle and explains much of the observed behavior of kaolin‐water systems.
Hydrogen Treating Process for Steel
Authors: HEALY J. H. , SULLIVAN J. D.
Published: June 2006

Steel is exposed to cathodically generated hydrogen until a decrease in density and an increase in porosity is obtained. The change in structure may be noted by ultrasonic mechanical vibrations. Upon the removal of a substantial portion of the hydrogen, glass may be applied to the steel and it will be free of high‐ and low‐temperature hydrogen defects. This process permits the use of (a) nonpremium steels, (b) nonbubbly mill additions, and (c) ground‐coat compositions that have greater corrosion resistance than conventional ground coats.
Quantitative High‐Temperature Oxidation of Porcelain Enameled Iron
Authors: LEFORT H. G. , FRIEDBERG A. L.
Published: June 2006

A continuous gain‐in‐weight method was used to measure quantitatively the oxidation taking place at elevated temperatures for long periods of time on enameled and unenameled iron. The oxidation was studied as a function of time and temperature on both bare and enameled iron. Specimens were subjected to variations in (1) enamel thickness, (2) thickness of electroplated‐nickel deposit, and (3) metal surface preparation of the iron. The rate of oxidation of enameled iron was lower than that of bare specimens at all temperatures. This effect was most significant at lower temperatures; it decreased in extent as the test temperature was increased to 1850°F. An increase in enamel thickness was very effective in reducing the rate of oxidation. To a lesser extent, an increase in nickel‐plate thickness on both enameled and unenameled specimens, and the use of sandblasting instead of mechanical abrasion and chemical cleaning as a method of metal preparation before enameling, also reduced the rate of oxidation. After the initial oxidation had proceeded at a linear rate, the oxidation rate of enameled and unenameled specimens followed a parabolic relation.
Subsolidus Relations Between Mullite and Iron Oxide
Authors: BROWNELL WAYNE E.
Published: June 2006

The subsolidus relations between mullite and iron oxide were studied to increase the understanding of the properties of fired clay products. Solid solutions of ferric oxide and mullite were measured in the temperature range 1000° to 1300°C. The solid solutions were characterized by an increase in the lattice dimensions of mullite, by increases in the indices of refraction, and by changes in color. Ferrous oxide did not enter into solid solution with mute but reacted with it to form ferrous aluminate and ferrous silicate. The exsolution of ferric oxide from mullite also was studied. The results were applied to the explanation of the fired color of clay products and to the control of these colors. The effect of the solution and exsolution of iron oxide on the dimensional changes occurring during the firing of clay products was noted.