bluuebunny/crossref_metadata_2025 huggingface dataset:
Design and Construction of a Self‐calibrating Dilatometer for High‐Temperature Use
Authors: LIEBERMAN A. , CRANDALL W. B.
Published: June 2006

A dilatometer has been constructed with minimum expense that operates with a specimen ¼ to ½ in. high, is self‐calibrating, indicates a motion of 2 × 10–6 in. accurately throughout a range of 0.10 in., is used to a temperature of 1400°C., and records its data automatically.
Viscosity Studies of System CaO–MgO–Al2O3–SiO2: III, 35, 45, and 50% SiO2
Authors: MACHIN J. S. , YEE TIN BOO , HANNA D. L.
Published: June 2006

In this continuation of previous papers on viscosity in the system CaO–MgO–Al2O3–SiO2, data are presented for melts containing 35% SiO2, 45% SiO2, and 50% SiO2 with varying percentages of the other three oxides that make up the system.
Boron Carbide as a Base Material for a Cermet
Authors: HAMJIAN H. J. , LIDMAN W. G.
Published: June 2006

An investigation was conducted to determine the bonding phenomenon in cermets after exposure at temperatures above the melting temperature of the metal. The experiments conducted with boron carbide and each of three metals showed that nickel, cobalt, and iron formed a bonding zone between the metal and the ceramic. The elevated temperature properties of a boron carbide cermet containing iron were investigated in the temperature range of 1600° to 2600°F. The properties evaluated were room‐ and elevated‐temperature modulus of rupture, resistance to fracture by thermal shock, oxidation characteristics, and density. These properties were compared with those of hot‐pressed boron carbide.
The Role of Titania in Silica Glasses
Authors: TURNBULL R. C. , LAWRENCE W. G.
Published: June 2006

A series of glasses in the system Na2O–SiO2–TiO2 were melted. Density measurements and refractive indices were determined. Molar refractions of the various glasses were calculated using the Lorentz‐Lorenz relationship. The partial molar refraction of TiO2, as determined in glass, corresponds closely with the values obtained from crystalline compounds and indicates that the Ti4+ ion exists in sixfold coordination. Interionic distances were calculated using the Kordes equation, the calculated Si–O distance being 1.60 a.u. and the Ti–O distance, equal to 2.01 a.u.
A Rapid Liquid‐Phase Adsorption Method for the Determination of the Surface Area of Clays
Authors: ORR CLYDE , BANKSTON P. T.
Published: June 2006

A relatively simple, rapid, and reliable method for the determination of the surface area of clays has been developed. The liquid‐phase adsorption of stearic acid, a surface active agent which under the proper conditions forms a unimolecular layer of orientated molecules on the solid surface, was employed. The method should be of value in making predictions regarding properties such as total adsorptivity, coloring power, and catalytic activity.
Significant Aspects of Certain Ternary Compounds and Solid Solutions
Authors: HUMMEL F. A.
Published: June 2006

The discovery of the thermal contraction of β‐eucryptite has introduced some new problems regarding the basic assumptions upon which previous thermal expansion theory has been based. These problems are presented together with a discussion of the chemical control of the thermal expansion of β‐eucryptite‐β‐spodumene solid solutions. The relationship of the solid solutions to the physical control of the thermal expansion of ceramic mixtures is presented.
Density Changes in Thermometer Glasses
Authors: LIBERATORE LAURENCE C. , WHITCOMB HELEN J.
Published: June 2006

A study was made of the density changes in the thermometer glasses, Corning 0041, 7560, 1720 and an experimental glass, Corning EXP175EK. Thermometers fabricated from these glasses were given similar heat‐treatments in their respective annealing ranges. Measurements were then made of the ice point changes at various fixed temperatures from room temperature to the normal upper useful limits of the glasses. Holding periods extended to 1 year. The ice point change in a thermometer is a measure of the per cent density change in the glass from which the bulb is fabricated. The relation of this change in density to temperature for a given duration of roasting appears to be well represented by two curves of the form of a constant times a temperature to a power. The value of the power appears to change rather abruptly at some temperature, T0, in the neighborhood of 150°C. below the strain point temperature and to be constant in the regions on either side of T0. At equal temperatures below the strain point the behavior of the glasses is quite similar.
On the Role of Nickel in Porcelain Enameling
Authors: KEELER J. H. , CHU P. K. , DAVIS H. M.
Published: June 2006

Nickel applied to a sheet steel as a nickel flash endures in the surface through several de‐enamelings and re‐enamelings. The attendant improvement in the enameling behavior of the steel is similarly persistent. Heat‐treating experiments with and without nickel lead to the conclusion that, while the fired ensemble is cooling, nickel oxide at the interface is reduced by hydrogen issuing from the steel, forming water which enters the enamel and diminishing the hydrogen available for defect production. In this function, a cobalt layer is comparatively ineffective.
Fused Stabilized Zirconia and Refractories
Authors: WHITTEMORE O. J. , MARSHALL D. W.
Published: June 2006

Production of fused stabilized zirconia directly from ores in an electric are fusion furnace is described. By this method, stabilized zirconia containing as low as 0.19% SiO2 has been made in one furnacing from an ore containing 33% SiO2. Various properties of refractories made from fused stabilized zirconia are listed. Uses have included linings for furnaces operating to 2500°C., setters for firing titanates, containers for steel and platinum, and resistors for oxide resistor furnaces.
Comparison of Warpage, Cross‐Bend, Torsion, and Expansiometer Ring Tests on Titania Enamels
Authors: LOCHRIDGE JAMES F. , MILLER GRANT E.
Published: June 2006

The fit of titania enamels as determined by warpage and the expansiometer ring tests is compared to torsion and cross‐bend failures. Tests were selected on the basis of normal use and acceptance by the industry. Titania enamels used for the tests cover a wide range of warpage values from low to high compression in the enamel. The major part of the work was conducted with the normal system of ground coat and cover coat. However, some comparative results are given for enamels applied directly on a titanium‐bearing steel. The data obtained are shown graphically.

It was found that warpage values and expansiometer ring values vary directly with the weight of application, and expansiometer ring values and warpage values are proportional. Cross‐bend values vary inversely with weight of application, and higher warpage enamels have higher cross‐bend values. Cross‐bend values are lower when enamel is applied directly than when the cover coat‐ground coat system is used; they are not affected by adherence variations. Torsion values in either system vary inversely with thickness. Torsion values do not vary according to warpage, ring value, or cross bend.
A Radioisotope Study of Cobalt in Porcelain Enamel
Authors: HARRISON WILLIAM N. , RICHMOND JOSEPH C. , PITTS JOSEPH W. , BENNER STANLEY G.
Published: June 2006

A typical porcelain enamel ground coat containing a small amount of radioactive cobalt as oxide was prepared, applied to sandblasted enameling iron blanks, and fired under conditions selected to give underfired, normally fired, and overfired coatings, respectively. Examination of these specimens revealed that a cobalt‐bearing metallic deposit had been formed at the enamel‐metal interface during firing, and that the enamel layer was depleted in cobalt oxide near the interface. The amounts of such deposit and depletion were found to vary directly with the severity of the firing treatment. The amount of metallic deposit was extremely small, on the order of 0.01 μ thick if computed as a continuous layer of metallic cobalt in the case of the normally fired specimens.
Influence of Al2O3, ZnO, and K2O on the Opacity of Fluoride‐Opacified Glasses
Authors: CALLOW R. J.
Published: June 2006

In the glass SiO2 71, Na2O 17, CaO 12% with 7.5 parts per hundred of fluorine added to the batch, substitution of up to 6% ZnO for CaO produced a great increase in the opacity; substitution of Al2O3 for SiO2 or of K2O for Na2O produced much smaller effects, which were dependent on the composition and were inappreciable in the presence of 6% ZnO. Despite the differences in opacity, no differences in fluorine content were detected. No support was found for the belief that Al2O3 is essential to the successful opacification of a glass by means of fluorides.
Wetting of Al2O3‐SiO2 Refractories by Molten Glass: II, Effect of Wetting on Penetration of Glass into Refractory
Authors: COMEFORO J. E. , HURSH R. K.
Published: June 2006

This portion of the investigation indicates the importance of the wetting behavior of molten glass to its rate of penetration into the same refractories studied in Part I. The principles concerning the penetration of liquids into porous solids are discussed. The rate of penetration of the glass into the refractories was evaluated by two methods with good correlation. Further information concerning the penetration of the glass into the refractories was obtained from a study of sections of the glass‐refractory interfaces. The relative resistance of each of the refractories to the penetration of the glass was evaluated. By a modification of the “pressure displacement method,” the effective pore sizes of the refractories were determined. The average pore radii of the refractories tested are compared. A break was observed in the relationship between the rate of penetration and the pore size of 99% alumina bodies with two liquids of markedly different properties. An explanation for this sudden change in the rate of penetration has been given, based upon the change in pore volume with change in pore radius.
A Method for Measuring the Flow Point of Glass
Authors: LILLIE HOWARD R.
Published: June 2006

The need for a new reference point for glasses, at a temperature substantially above the softening point, is discussed from the standpoint of development of. new glasses, control of properties, and behavior in applications where reworking is required. An apparatus and a procedure are described by which a fiber elongation test indicates the “flow point,” or temperature at which a glass reaches a viscosity of 105 poises. A short section of a glass fiber, nominally 0.65 mm. in diameter, is heated under specified conditions of load and heat application. The heating time required for the fiber to draw down to a thread indicates the temperature attained. When properly standardized with one or more known glasses, the precision is equivalent to from 1°C. for soft glasses to 5°C. for hard glasses. The effect of infrared absorption by the sample is examined, and a correction curve is given for use when such absorption is abnormally great.
Surface Tension of Molten Alkali Borates
Authors: SHARTSIS LEO , CAPPS WEBSTER
Published: June 2006

The surface tensions of a series of lithium, sodium, and potassium borate melts were measured by a maximum pull‐on‐cylinder method. All the alkali oxides raised the surface tension. In the high‐alkali range the order Li+ > Na+> K+ was observed for surface tension and for the algebraic value of the temperature coefficient of surface tension. In the low‐alkali range (up to 15 mole %) the order of surface tension was K+ > Na+ > Li+ and the temperature coefficients of surface tension, independent of the type or concentration of alkali ion, had approximately the same value as that of B2O3. This behavior was interpreted as a tendency toward immiscibility limited to surface phenomena. Correlation was observed between alkali content, volume expansivity, and temperature coefficient of surface tension.
Study of Silica Brick from a Glass Tank Crown
Authors: CHRZAN E. S. , PETRIE E. C. , SWAIN S. M.
Published: June 2006

Silica brick after service in the crown of a glass tank were carefully examined for alteration. Test specimens were selected by color zones and other evidence of change. The results show appreciable absorption of soda, which lowers the refractoriness of the brick but also promotes growth of large crystals of tridymite or cristo balite. A tentative explanation of “rat‐holing” is given and a means of reducing the attack is suggested.
Fundamental Aspects in Research on Titania‐Opacified Enamels
Authors: COLE SANDFORD S.
Published: June 2006

Vitreous enamels opacified by titanium dioxide were shown to be affected by the composition of the glassy matrix, solubility of titanium oxide in the matrix, viscosity of the glass, and concentration of titanium oxide in the glass. The color and opacity of these enamels are influenced by the particle size of the precipitated oxide, crystalline form of the oxide, and type of nuclei. The cationic and anionic addition agents were shown to influence crystal habit, color, and nucleating properties.
Some Applications of the Fluorescent X‐Ray Spectrometer in Ceramics
Authors: PATRICK ROBERT F.
Published: June 2006

The theory behind fluorescent X‐ray spectroscopy is briefly reviewed. X‐ray spectrometers are designed for the rapid qualitative and quantitative analysis of elements having an atomic number greater than 22 (titanium). This technique has been used to determine quantitatively the nickel plated out in nickel pickling and the amounts of cobalt and nickel deposited on the base metal during the firing of enamel ground coats. The method has been used to determine the lead content of a glaze frit. The X‐ray spectrometer can be used satisfactorily for the analysis of specific elements, above titanium in atomic number, in virtually any raw material. For example, iron in pyrophyllite and niobium in titania have been determined quantitatively. The advantages and disadvantages of this technique are discussed.
Calculated X‐Ray Mass Absorption Coefficients of Glass Components
Authors: BREWSTER GORDON F.
Published: June 2006

X‐ray mass absorption coefficients of some elements and oxides used in glassmaking have been computed from 0.01 a.u. (1234 kv.) to characteristic K absorption edges. Using these values, the absorption of X rays by a glass in the wavelength range considered can be readily calculated from its composition expressed in weight fractions of oxide components and its density.
Glaze Investigations: II, Effect of Composition Variation in Glazes Containing Diatomaceous Silica
Authors: RUSSELL RALSTON , ROWLANDS ROBERT R.
Published: June 2006

An investigation was made of the effect of variations in RO constituency and in Al2O3 and SiO2 contents of Bristol‐type glazes in which diatomaceous earth was the primary source of silica. The effects on appearance and glaze fit were determined, with particular emphasis on the relation between ware strength and glaze stress. It is indicated that there is a limit to the ware strength improvement which may be effected by an increasing degree of glaze compression. It is also significant that the use of diatomaceous silica as a primary glaze constituent affords extreme flexibility in the choice of glaze compositions yielding a satisfactory combination of maturation, appearance, and glaze‐fit characteristics.
Application of Rate‐Process Theory to Glass—Electrical Conductivity
Authors: STUART DERALD A. , ANDERSON ORSON L.
Published: June 2006

The electrical conductivity of glass has long been known to be a function of temperature and composition, this fact being first established empirically by Foussereau in 1882. The temperature dependence of the resistivity would seem, however, to follow different laws at high and at low temperatures. Using the rate‐process theory, an equation is developed giving the dependence of the resistivity versus temperature. It is shown that at high and low temperatures the equation is reducible to the known empirical forms. It is also shown that glass may be nonohmic in character at low temperatures, as reported by Poole. Poole's equation for the dependence of the resistivity on field strength furthermore is shown to be a direct consequence of the theory.
Some Ceramic Properties of Halloysite
Authors: HAMPEL BRUCE F. , CUTLER IVAN B.
Published: June 2006

The analysis of four clays originating in Utah indicates that they consist almost entirely of the mineral halloysite. Extruded specimens of these clays show particle alignment and on firing produce large differential shrinkages. The properties of one of the clays were investigated after a low‐temperature calcination process. In all cases excessive shrinkages were observed that may be explained on the basis of particle structure.
Uranium Oxide Phase Equilibrium Systems: II, UO2–MgO
Authors: LAMBERTSON W. A. , MUELLER M. H.
Published: June 2006

A slight oxidation of UO2 by MgO was found to occur at high temperatures although no compounds or solid solution were detected. The eutectic was between 70 and 80% MgO at about 2100°C.
Ferroelectric Properties of Lead Metaniobate
Authors: GOODMAN G.
Published: June 2006

Ferroelectric lead metaniobate, Pb(NbO3)2, is structurally distinct from the ABO3 perovskite‐type ferroelectrics presently known. Dielectric and dilatometric data indicate a 570°C. Curie point. In ceramic form the material can be polarized to retain a piezoelectric constant of the same order of magnitude as that of barium titanate.
Weight Loss and Oxidation Behavior of Structural Bodies During Firing
Authors: VAN DER BECK R. R. , EVERHART J. O.
Published: June 2006

A thorough study of the factors which affect the firing behavior of structural clay materials is reported. The twenty materials which were investigated for length‐change behavior previously (J. Am. Ceram. Soc., 34 [12] 361–65 (1951)) were studied for oxidation behavior. The methods of investigation which were used on these materials included differential thermal analyses, oxidation‐rate determinations, and length‐change determinations. The technique employed in securing the data, as well as a discussion of the results, is given. Particular emphasis is placed on the manner in which the information was used to draft firing schedules. Changes in fuel and time are cited. It was found that the carbon oxidation rate is influenced considerably by temperature; some types oxidize rapidly at 1000°F.; others oxidize slowly at 1000°F. and rapidly at 1400°F.
Some Effects of Titania on Refractory Clays
Authors: WILDER DAVID R. , DODD C. M.
Published: June 2006

The amount of titania a clay can contain without appreciably lowering its refractoriness was determined. A soft flint fire clay, a hard flint fire clay, and a kaolin with varying percentages of titania added were fired to 2840°F. and examined. The influence of titania on the glassy material formed was found to be the same in each of the three clays considered. This was indicated by both apparent porosity determinations and examination of thin sections under the petrographic microscope. The most rapid increase in the development of glassy material occurred when from 3 to 4.5% titania was added to the clay.
Dependence of Ultimate Strength of Glass Under Constant Load on Temperature, Ambient Atmosphere, and Time
Authors: STUART DERALD A. , ANDERSON ORSON L.
Published: June 2006

It is widely known that the strength of glass specimens is strongly dependent on many factors, including (1) the flaws and/or scratches on the surface, (2) the ambient atmosphere, (3) the temperature, (4) the duration of the test, and (5) the type of stress system imposed on the specimen. In this paper the authors develop several equations that relate the average strength of glass under constant load to the duration of the test, to the temperature of the test, and to the ambient atmosphere. The data of T. C. Baker and his co‐workers are used to calculate the various parameters which appear in the resultant equations. Additional experiments are suggested as a basis for further verification and/or modification of the theory.
Density and Expansivity of Alkali Borates and Density Characteristics of Some Other Binary Glasses
Authors: SHARTSIS L. , CAPPS W. , SPINNER S.
Published: June 2006

The densities of liquids in the systems Li2O–B2O3, Na2O–B2O3, and K2O–B2O3 were measured by a counterbalanced‐sphere method over the approximate temperature range 600° to 1000°C. The room‐temperature densities of alkali borate glasses were also measured. Density increased with increasing percentages of alkali oxide below 30 mole %. At high temperatures the density‐composition curves showed maxima at about 30 mole % alkali oxide. Expansivities over various temperature ranges were calculated from change of density with temperature. Expansivities in the liquid range increased with alkali content. In the low‐alkali region, expansivity in the liquid range decreased with rising temperature whereas contrary behavior was noted in the high‐alkali region. The most striking effect caused by the addition of alkali to B2O3 was a volume contraction. Some reasons were found to account for the lack of agreement with experimental observations of the methods of Huggins and Stevels for calculating densities.
Use of Free Energy Data in the Construction of Phase Diagrams
Authors: KNAPP W. J.
Published: June 2006

A review is given of the use of free energy‐composition curves in binary systems for determining the range of composition over which a phase, or combination of phases, is stable at a specified temperature (at constant pressure). Phase boundaries may be constructed in the usual temperature‐composition phase diagram from reference to free energy‐composition curves for several temperatures. Examples are given of the construction of phase diagrams for the systems Ca2B2O5–CaSiO3 and Al2O3–Cr2O3. The method described involves an assumption of ideal solution behavior, and is limited in application to systems where ideal solutions are approximàted.
Clay‐Slip Testing with the Vibrating‐Plate Viscometer
Authors: PHELPS G. W. , WOODWARD J. G. , MAGUIRE S. G.
Published: June 2006

A series of artware and sanitary‐ware slips was tested using the vibrating‐plate viscometer. Results obtained with this instrument are in the form of “casting curves” that depict slip consistency as a function of time during the casting operation. Various features of the casting curves are compared with data obtained by more conventional test procedures. Correlations are found between casting‐curve parameters and such factors as initial slip fluidity, casting rate, retained water, and quality of finished cast. The physical significance of certain aspects of the casting curves is discussed.
Induction Firing in the Study of Furnace Atmospheres
Authors: PLANKENHORN W. J. , ANDREWS A. I.
Published: June 2006

A method involving induction heating was devised whereby porcelain enameled specimens were fired in gastight glass tubes in which the atmosphere could be controlled and the gases and vapors collected. The progress of the processes of oxidation of the metal and volatilization of the coating were followed by carefully weighing specimens heated under varied conditions. The results confirmed the general conceptions with regard to the effects of oxidation on enamel adherence and structure. Volatilization of the enamel was evidenced by the deposition of an extremely fine powdery material on the walls of the firing chamber which was studied by spectrographic and X‐ray diffraction techniques.
Electrical Resistance of Some Refractory Oxides and Their Mixtures in the Temperature Range 600° to 1500°C.
Authors: HENSLER J. R. , HENRY E. C.
Published: June 2006

Measurements of electrical resistance in the composition systems Al2O3–SiO2, SiO2–TiO2, Al2O3–Cr2O3, and MgO–NiO were made using, in general, dry‐pressed disks about 3 cm. in diameter and 0.4 cm. thick and fired to 1500°C. In the Al2O3–SiO2 series minimum resistance was shown by the samples containing 50% SiO2, 50% Al2O3. The resistance of Al2O3 was increased by the addition of small amounts of Cr2O3. The same effect was observed in the higher temperature range with small additions of NiO to MgO. In other instances the addition of the relatively inert SiO2, Al2O3, and MgO to the semiconductors TiO2, Cr2O3, and NiO resulted in a dilution effect. The resistance of Cr2O3 was decreased by the addition of a slight amount of MgO.
Helium Diffusion Through Glass
Authors: NORTON FRANCIS J.
Published: June 2006

Using the mass spectrometer as an analytical tool and as a means of rate measurement, the rates of helium diffusion through nine types of glass were measured. The temperature range covered was from –80° to 600°C. The highest rates were for fused silica and Vycor brand glass; the lowest were for the lead glasses. The rate at 100°C. decreased by a factor of one million as the percentage of glassformers (SiO2, B2O3, P2O5) decreased in the glass composition. A few measurements are also given for hydrogen, deuterium, and neon rates through fused silica and estimates are made of the upper limit for argon, oxygen, and nitrogen at 700°C.
Prestressed Ceramics as a Structural Material
Authors: JOHNSTON R. D. , CHIPMAN R. D. , KNAPP W. J.
Published: June 2006

The compressive strengths of most ceramic products are seven to ten times greater than their respective tensile strengths. If ceramic structural members are kept in compression by prestressing, they are capable of carrying much larger loads than members with no prestressing. Through application of the principle of prestressing, tensile stresses are avoided. Results of preliminary experiments with prestressed ceramic members are described. The test findings indicate that prestressing gives marked improvement in resistance to failure in both static and impact loadings. Some possibilities are suggested for using prestressing methods with ceramic materials.
Temperature Gradient Method for Determining Firing Range of Ceramic Bodies
Authors: Stone Robert L.
Published: June 2006

An improved version of Steger's temperature gradient method of studying the firing behavior of ceramic bodies, clays, and glazes is given. The test specimen (8 in. long) is subjected, from one end to the other, to a temperature gradient of several hundred degrees. Such properties as shrinkage, hardness, bloating, crazing, and color are observed for the entire range of temperature. Furnace design and method of plotting results are given.
Some Factors Affecting the Testing of Surface Durability of Flat Glass
Authors: SIMPSON H. E.
Published: June 2006

The surface durability of flat glass was studied by subjecting the glass to cycles of surface fogging and clearing. The total transmission and the amount of scattered light of the weathered samples were measured with a photoelectric haze meter, the relative amount of scattering being considered as a measure of the amount of haze or surface deterioration. Some factors influencing the test were considered, especially the age of the samples and previous conditions of storage. Comparisons were made between ground and polished surfaces and fire‐polished surfaces. The effects of acid and alkali treatment on the durability of the surfaces were also studied.
Metallographic Examination of Ceramic‐Metal Seals
Authors: PINCUS A. G.
Published: June 2006

The making of taper sections of ceramic‐to‐metal seals is described. Their usefulness is illustrated by applications to (1) research into adherence mechanisms and (2) production trouble shooting. The laboriousness and pitfalls in taper‐section preparation and interpretation are stressed. In spite of them the technique has been the most productive approach to understanding and controlling the seal art.
Note on Modulus of Rupture of Cylindrical Ceramic Rods When Tested on a Short Span
Authors: MILLIGAN LOWELL H.
Published: June 2006

It is known that for rectangular bars corrections are necessary for the simple modulus of rupture farmula to obtain true cross‐bending strengths when the ratio of span to bar depth is less than about 10:1. The experiments described in this note develop empirical data on this subject for cylindrical rods of low span‐to‐diameter ratios.
A Theory of Cation Exchange Reactions with Clay Minerals
Authors: CUTLER IVAN B. , COOK MELVIN A.
Published: June 2006

A consideration of the possible cation exchange reactions with clay‐mineral surfaces in aqueous media leads to an equilibrium expression with which it is possible to obtain a good correlation of data in the literature. Free‐energy considerations based on approximate equilibrium constants also support the theory. The ionic‐strength contribution of the various clay minerals is shown to be large enough to account for displacement of curves due to differences in clay‐water concentration.
Interference Films on Glass: II, Some Observations During Acid Leaching of X‐Ray Plate Glass
Authors: ANDERSON SCOTT , KIMPTON D. D.
Published: June 2006

The variation of the infrared reflection spectrum of acid stain films on X‐ray shield glass has been studied as a function of leaching time in HCl. This work supports the conclusion that the major process involved in film formation on this glass is the diffusion of lead (in modifier position) out of the glass surface. It is indicated that a small portion of the lead is in the original glass network in definite coordination with oxygen. The spectra reveal that this lead is removed with considerably more difficulty than the lead in modifier positions. If it is postulated that the modifying lead ions can diffuse more readily through the skeleton network of the film when the coordinated units are present than after they are removed, it is found that the rate of stain formation should proceed initially along a straight line followed by a growth proportional to t1/3. This agrees with the observed rates.
Electrical Conductivity of Some Commercial Refractories in the Temperature Range 600° to 1500°C.
Authors: CHIOCHETTI V. E. J. , HENRY E. C.
Published: June 2006

The electrical resistance of specimens cut from commercial refractory brick was measured in the temperature range 600° to 1500°C. Log of resistivity plotted against reciprocal absolute temperature gave curves that are compared with those obtained by Hensler for sintered c.p. oxide mixtures. Curves for c.p. alumina‐silica mixtures, fire‐clay brick, high‐alumina brick, mullite‐type brick, and fused‐cast alumina brick containing some chromite are straight lines such as are obtained for material following the Rasch and Hinrichsen rule, ρ=AeB/T. Silica brick, fused‐cast alumina brick, and high‐silica mixtures show slight deviation from this rule. Fused‐cast alumina brick containing both α‐ and β‐Al2O3 and basic brick and basic oxide mixtures exhibit a different type of curve. A plot of log ρ vs. 1/T(°K.) is presented for each material tested, accompanied by pertinent data.
Fluoride Model Systems: III, The System NaF–BeF2 and the Polymorphism of Na2BeF4 and BeF2
Authors: ROY DELLA M. , ROY RUSTUM , OSBORN E. F.
Published: June 2006

A revised equilibrium diagram is presented for the system NaF–BeF2, a weakened model of the system CaO–SiO2. The compound Na2BeF4 has four structural modifications corresponding to the γ, β, α', and α forms of Ca2SiO4. Inversion temperatures were found to be as follows: α→α’= 320°C., γ→α’= 225°C., α’→β (metastable) = 115°C. The quartz form of BeF2 was found to have a high‐low inversion at 220°C. The high‐quartz form exists in equilibrium with liquid in binary fluoride systems up to the melting temperature of BeF2, as closely as can be determined. The cristobalite form appears to have only a metastable existence, and a tridymite form has not been found. The compound NaBeF3 has a structure similar to β‐CaSiO3 below 343°C., with a different structure (not that of α‐CaSiO3) above this temperature.
Sonic Analysis for Solid Bodies
Authors: AULT NEIL N. , UELTZ H. F. G.
Published: June 2006

A method is described for determining the variation of the modulus of elasticity of solid bodies with respect to temperature. Sonic frequencies of various ceramic materials made into bar specimens were determined at various temperatures, and modulus of elasticity values were then calculated. The effect on the modulus of elasticity of a crystalline inversion within a bar was apparent even though the inverting material was a small percentage of the bar composition. Various other effects that change Young's modulus with temperature were also observed. Examples of the method are given and an analysis of results is presented.
Permeability and Some Other Properties of a Variety of Refractory Materials: I
Authors: MASSENGALE G. B. , MONG L. E. , HEINDL R. A.
Published: June 2006

Flatwise, edgewise, and endwise permeabilities, bulk densities, moduli of elasticity, and porosities were determined for the following types of refractory brick as received from the manufacturers: fire‐clay, insulating, mullite, silica, kaolin, high‐alumina, acidproof, magnesite, unburned magnesite‐chrome, and unburned chrome‐magnesite. These properties were determined also for specimens (1) of the unburned brands of the chrome‐magnesite and magnesite‐chrome brick after heat‐treating at 925° and at 1600°C., (2) from the side wall of a clay pot after heat‐treating at several temperatures, and (3) from the side walls of two other pots and the bottom of one after heat‐treating at 1400°C. only. For refractory brick, flatwise permeability was least and edgewise greatest; permeability was not closely related to the other determined properties. Sintering caused larger increases in the permeability than the (partial) decomposition of the chemical binder of unburned basic brick. Of the determined properties of specimens cut from the pots, permeability was the most sensitive to heat‐treatment and was the best criterion of resistance to molten glass. Permeability, modulus of elasticity, and bulk density increased whereas bulk volume and porosity decreased with successively higher heat‐treatments for the pots.
Further Evidence Against the Orientation of Structure in Glass Fibers
Authors: BRANNAN RALPH T.
Published: June 2006

The elastic properties of fine glass filaments of high strength lend no support to the view that the strong bonds are preferentially oriented. In particular, Poisson's ratio has a normal value very similar to that of massive glass. Furthermore, heat‐treatment of these fibers does not change Poisson's ratio.
Effect of Partial Devitrification on the Electrical Resistivity of Sodium‐Bearing Glasses
Authors: JOYNER BOBBY L. , BELL WILLIAM C.
Published: June 2006

The effect of partial devitrification on the electrical resistivity of three sodium‐bearing glasses has been determined. Resistance measurements were made over a range of temperatures from 130° to approximately 550°C. The resistivity of the glasses studied was found to be influenced by partial devitrification; the nature of this change was found to be proportional to the change in Na2O content of the glassy phase remaining after devitrification. The results show that the change in resistivity can be predicted by phase equilibrium diagrams.
Study of Some Phenomena Associated with the Adherence of Sheet Iron Ground Coats
Authors: PATRICK R. F. , PORST E. G. , SPENCER‐STRONG G. H.
Published: June 2006

Cobalt and nickel are deposited on the surface of the base metal during the firing of sheet iron ground coats. These deposits, which are metallic in nature, at least at higher firing temperatures, increase with increasing firing temperature. They also increase with the amount of cobalt and nickel present in any one frit and with the fluidity of the enamel. One reason why cobalt is generally considered a better adherence agent than nickel is that cobalt has a greater tendency to deposit during firing. Ground‐coat adherence is generally associated with a certain amount of deposition of cobalt and nickel on the metal surface. This deposition in turn is associated with a roughening of the metal surface which is believed to be a large contributory factor in enamel adherence.
Galvanic Corrosion Theory for Adherence of Porcelain Enamel Ground Coats to Steel
Authors: MOORE D. G. , PITTS J. W. , RICHMOND J. C. , HARRISON W. N.
Published: June 2006

The galvanic corrosion theory of adherence between ground‐coat enamels and steel was investigated as a part of a broad study of the bonding mechanism between ceramics and metals. The theory, which is outlined in this report, is based on the mechanical anchoring of the enamel into the pits formed by the galvanic attack of the enamel on the steel surface. The theory was first examined from the standpoint of the data on adherence obtained in earlier studies at the National Bureau of Standards. In addition, several experiments were performed which demonstrated that galvanic corrosion of the metal base could occur during the short firing times encountered in enamel processing. On the other hand, certain inconsistencies were observed in the data which indicated that the mechanism of galvanic attack followed by mechanical anchoring was not the only important factor affecting the bond strength.
Phase Equilibria in the System Lithium Metasilicate–β‐Eucryptite
Authors: KRISHNA MURTHY M. , HUMMEL F. A.
Published: June 2006

A phase equilibrium study of the join lithium metasilicate–β–eucryptite in the system Li2O–Al2O3–SiO2 was made by the quench method. The phase diagram was found to be a simple binary with a eutectic at 1070°C and 57% eucryptite. The relationship of these data to the ternary system is discussed.
Energy Relations in Binary Alkali Borates
Authors: SHARTSIS L. , CAPPS W.
Published: June 2006

The heats of solution of glasses and devitrified alkali borates in the systems Li2O–B2O3, Na2O—B2O3, and K2O–B2O3 were measured in 2 N nitric acid with a simple vacuum‐bottle calorimeter. The standard deviation was 0.35 cal. per gm. for approximately 130 determinations. From these data, together with available thermodynamic data, heats of formation were calculated for alkali borate glasses and devitrified alkali borates from two combinations of possible reactants. All the curves for the heats of solution of glasses showed minima at 20 mole % alkali oxide, but similar curves for devitrified alkali borates showed minima at 20 mole % for potassium and sodium borates only. The curve for devitrified lithium borates showed a minimum at 25 mole % alkali. The conclusion was drawn that there is probably no congruently melting Li2O.4B2O3 compound.
Application of Sonic Moduli of Elasticity and Rigidity to Testing of Heavy Refractories
Authors: WILLMORE T. A. , DEGENKOLB R. S. , HERRON R. H. , ALLEN A. W.
Published: June 2006

The application of A.S.T.M. C 215‐51 T (Tentative Method of Test for Fundamental Transverse Frequency of Concrete Specimens for Calculating Young's Modulus of Elasticity) to the nondestructive testing of 1‐ by 1‐ by 7‐in. laboratory fire‐clay specimens and standard 9‐in. fire‐clay and high‐alumina refractory brick is reviewed. Both room‐temperature measurements and hot sonic modulus of elasticity measurements to 1700°F. are analyzed. Sonic moduli of elasticity and rigidity are compared with modulus of rupture by a theory of measurements and statistical analysis. The limits of uncertainty of the average of modulus of rupture are shown to be a function of the degree of verification whereas in the case of both sonic moduli they are not. Limits of uncertainty of the average of sonic moduli data are usually of the same order as errors calculated from the precision of measurements. In the case of modulus of rupture of well‐vitrified clays, the uncertainty of the average is much greater than calculated error limits. Sonic moduli differentiate statistically between two samples of 60% alumina brick whereas modulus of rupture does not. If Poisson's ratio is assumed to be zero rather than the conventional one‐sixth, ratios of sonic modulus of elasticity to rigidity are shown to approximate the theoretical ratio more closely. Effects of nonuniform density to displace normal nodes are illustrated. Hot sonic modulus of elasticity is shown to reflect changes due to crystallographic inversions, deterioration of chemical bond in unfired brick, and development of sintered bond in unfired brick.
Some Properties of Hafnium Oxide, Hafnium Silicate, Calcium Hafnate, and Hafnium Carbide
Authors: CURTIS C. E. , DONEY L. M. , JOHNSON J. R.
Published: June 2006

The behavior of hafnium oxide was studied particularly in the temperature range 1500° to 18OO°C. Properties of HfO2 at these temperatures and its reactions with ZrO2, SiO2, and CaO are given in terms of lattice and other physical measurements, many of which are new. Mono‐clinic hafnium oxide is stable to 1700°C., which is 600° higher than the corresponding inversion temperature of zirconia. Otherwise HfO2 closely resembles ZrO2 (a) in its lattice dimensions and sintering behavior, (b) in forming a high‐temperature tetragonal phase closely resembling tetragonal ZrO2, (c) in forming a continuous series of solid solutions with ZrOz, (d) in forming with silica a single compound (HfO2.SiO2) similar to zircon, (e) in forming a carbide, (f) in uniting with up to 40% CaO to form cubic solid solutions; thereafter a compound CaO.Hf O2 appears which is very similar to the corresponding zirconia compound.
Dielectric Bodies in Metal Stannate‐Barium Titanate Binary Systems
Authors: COFFEEN WILLIAM W.
Published: June 2006

Ceramic and dielectric properties of bodies in the binary systems of barium titanate plus the stannates of magnesium, lead, bismuth, zinc, nickel, copper, cadmium, cobalt, manganese, and iron have been investigated. Bodies in the system tin oxide‐barium titanate also have been evaluated. Additions of tin oxide, lead stannate, cadmium stannate, zinc stannate, and copper stannate progressively decrease the Curie temperature of the body. Lead stannate bodies exhibit somewhat flatter peaks than the others and show much less variation of dielectric constant with temperature than do similar bodies prepared with the stannates of barium, calcium, or strontium. Additions of magnesium stannate, bismuth stannate, and nickel stannate greatly depress the Curie peak of barium titanate bodies. Bismuth stannate is particularly effective in producing bodies with very low temperature coefficient of dielectric constant. Bodies having dielectric constants of 4000 to 5000 (+25%, −50% from −60° to 85°C.) may be obtained from compositions containing about 15 mole % PbSnO3. Bodies having dielectric constants of 2000 to 2300 (+ 10%, −40% from −60° to 85°C.) may be obtained from compositions containing about 4 or 5 mole% of either MgSnO3or NiSnO3. Bodies having dielectric constants of 1000 to 1200 (−4% from −60° to 85°C.) may be obtained from compositions containing about 5 mole % Bi2(SnO3)3. Limited data indicate that the aging of various compositions apparently increases with level of dielectric constant. Non‐linearity with d.‐c. bias is greatest for high peak‐K bodies. Up to the limits investigated, additions of CaSnO3, PbSnO3, MgSn03, and Bi2 (SnO3)3 are absorbed in BaTiO3 bodies as solid‐solution‐type simple cubic structures with slightly expanded lattices.
Surface Tension, Density, Viscosity, and Electrical Resistivity of Molten Binary Alkaline‐Earth Borates
Authors: SHARTSIS LEO , SHERMER H. F.
Published: June 2006

Results of an investigation of some properties of the systems CaO‐B2O3, SrO‐B2O3, and BaO‐B2O3 are reported. The formation of two liquids at low RO concentrations limited the range of compositions which could be measured. The values of surface tension and temperature coefficient of surface tension obtained for compositions where two immiscible liquids exist corresponded closely to those for pure B2O3. At RO concentrations above the two–liquid regions the surface tension rose sharply with increasing RO content. The densities in the liquid range as well as at room temperature were in the order Ba > Sr > Ca. The introduction of RO into B203 caused contractions in the glass network; the order of the contracting effect was Ca > Sr > Ba. Neither the method of Huggins or of Stevels was satisfactory for representing the density behavior of these glasses. The viscosity isotherms of barium borate liquids in the temperature range 850° to 950°C. showed maxima at about 22 to 23 mole yo BaO; the other two systems were too fluid for the counterbalanced sphere apparatus used in this work. The equivalent conductance increased with RO concentration; the order for both specific and equivalent conductance at corresponding concentrations was Ba > Sr > Ca.
Variables in the Load Test for Fire–Clay Refractories
Authors: BROWN WILLIAM E. , SOSMAN ROBERT B.
Published: June 2006

The so–called load test, as applied to refractory fire–clay brick, was studied from two points of view. The present A.S.T.M. standard test procedure is found to give results, on specimens smaller than the standard size, that depend on the cross section and length of the specimen. A more informative and more reliable test, constituting the second part of the study, consists in recording the curve of deformation against time at a constant temperature. The deformation of fire–clay brick at 2100° to 2550°F. is an exponential function of temperature, and the flow up to 24 hours fits the equation for flow of glass. At constant temperature, between 2100° and 2550°F., the permanent deformation after cooling is proportional to the load for the range 15 to 40 lb. per sq. in.
Experimental study of Fractue of Glass: II, Experimental Data
Authors: SHAND ERROL B.
Published: June 2006

Original studies and experiments that support the concept of the close association between fracture origin and flaws in glass are presented. The effect of temporary overstresses, fracture velocities during the later development of the process, and evaluation of the critical stress are discussed. Data are presented which show that temporary overstresses may weaken glass permanently and that this effect results from the slow propagation of fracture flaws. The study of fracture surfaces reveals that the velocity of the fracture crack across the section is not necessarily uniform and that the velocity characteristics of each individual fracture are determined by factors such as degree of load relaxation occurring during the dynamic phase of the process. The critical stress is estimated to be between 2.5 and 5 million lb. per sq. in., and, for any particular glass, this stress is independent of test conditions.
Calculation of Activation Energy of Ionic Conductivity in Silica Glasses by Classical Methods
Authors: ANDERSON O. L. , STUART D. A.
Published: June 2006

An equation for the activation energy of ionic conduction in silica glasses is developed. The approach uses the classical ideas of ionic crystal theory and elasticity theory. The equation finally derived involves the radius and valence of the modifier ion, the lattice constant of the glass, the electronic charge, the shear modulus, and three arbitrary parameters. Two of these parameters are shown to be related to the geometry of the silica network and are exactly determined from diffusion of gases in glass data. The other parameter is shown to be approximately numerically equal to the dielectric constant. he theory is compared with the experimental results of 140 glass compositions.
Fundamental Study of Clay: XIII, Drying Behavior and Plastic Properties
Authors: KINGERY W. D. , FRANCL J.
Published: June 2006

The effects of nonionic, anionic, and cationic surface‐active agents on yield point, plasticity, drying and firing shrinkage, dry and fired density, and rate of drying have been experimentally determined. These and other factors have been correlated on the basis of a comprehensive theory of the plastic properties and drying behavior of clay‐water masses.