bluuebunny/crossref_metadata_2025_split huggingface dataset:
IMPROVING THE QUALITY OF EXTRUDED MILL BRICK*
Authors: SCHURECHT† H. G. 
Published: June 2006

AbstractIn the production of extruded brick for lining ball mills, unevenness of the brick such as (1) bow, (2) diagonal twist, (3) sunken faces, (4) depressed and bulged ends, and (5) underfired and cracked centers were reduced by (1) adjusting the die, (2) using grids behind the die, (3) controlling the drop from the die to the cutting table, (4) adjusting the tilt of the cutting table, and (5) stacking the brick during drying. The specific gravity was increased as much as 3.3% by using improved methods of setting the brick in saggers.
MEASUREMENT OF ENAMEL‐SLIP CONSISTENCY BY MEANS OF THE BROOKFIELD VISCOSIMETER*
Authors: Oliver Evan M. 
Published: June 2006

AbstractAn instrument commonly employed to measure the viscosity of truly viscous liquids was tested to determine its applicability for evaluating consistencies of enamel slips which are solid suspensions in a water medium. Within wide limits of specific gravity differences and variations in set resulting from electrolyte additions, the Brookfield vis‐cosimeter afforded comparable information with the pick‐up and slump tests employed as references.
A NEW METHOD FOR STUDYING FRACTURES OF PORCELAIN ENAMELED SPECIMENS*
Authors: Petersen F. A. , Jones Rodney A. , Allen A. W. 
Published: June 2006

AbstractA process is described which locates microscopic cracks in an enamel layer. This method shows great promise in the study of different types of fractures of porcelain enameled specimens. An analysis of the stress conditions in the enamel‐iron‐enamel system before, during, and after thermal shock is also included.
VISCOSITY STUDIES OF SYSTEM CaO‐MgO‐Al2O3‐SiO2: II, CaO‐Al2O3‐SiO2*
Authors: Machin J. S. , Yee Tin Boo 
Published: June 2006

AbstractViscosity data are presented covering those compositions in the CaO‐Al2O3‐SiO2 system which are liquid at 1500°C. The pattern of isokoms on the CaO‐Al2O3‐SiO2 face of the compositional tetrahedron which represents the CaO‐MgO‐Al2O3‐SiO2 system is a system of lines which roughly parallel the lines along which the lime content is constant. There are, however, considerable deviations from this parallelism in regions of very low and very high alumina content.
SOME ENERGY RELATIONS IN THE SYSTEMS PbO‐B2O3 AND PbO‐SiO2*
Authors: Shartsis L. , Newman E. S. 
Published: June 2006

AbstractHeats of solution of a series of glasses in the system PbO‐B2O3 were measured in 2 N nitric acid with a simple vacuum‐bottle calorimeter. Heats of solution of a series of glasses in the system PbO‐SiO2 ranging in composition from 6 to 35% of SiO2 were measured in a mixture of HF and 2.5 N nitric acid with an electrically calibrated isothermal jacket calorimeter. From these data and heats of fusion available in the literature, calculations were made of the heats of reaction of the component oxides in either amorphous or crystalline states in forming glasses in these systems.
EFFECT OF SIZE AND SHAPE OF TITANIUM OXIDE CRYSTALS ON SPECTROPHOTOMETRIC PROPERTIES OF TITANIUM‐BEARING PORCELAIN ENAMELS*
Authors: Friedberg A. L. , Fischer R. B. , Petersenr F. A. 
Published: June 2006

AbstractColor changes of three titanium enamels given varied firing treatment were investigated. The size and shape of titanium oxide particles were studied with the electron microscope, the relative amounts of anatase and rutile were determined from X‐ray analyses, and spectrophotometric curves of the fired panels were made.Electron micrographs showed that rutile particles recrystallized as needles or “sticks,” whereas anatase appeared as ill‐defined, irregularly shaped, rounded particles. With increasing firing temperature or firing time (1) rutile particles showed a greater increase in size than anatase particles, (2) the amount (by weight or volume) of anatase crystals decreased and the amount of rutile crystals increased, and (3) a color change from blue‐white to cream‐white was observed.The change in color seemed to be related to the scattering of blue light by small particles at lower temperatures or shorter periods of firing. As the size of opacifying particles increased, the scattering of blue light decreased, and the characteristic absorption of visible light in the shorter wave lengths was more apparent. In enamels containing both anatase and rutile, the smaller anatase crystals were predominant at lower and the larger rutile crystals at higher temperatures, so that sharp changes of color were observed as the firing temperature was increased.
Some Physical and Chemical Properties of Experimental Glazes for Vitrified Institutional Whiteware
Authors: KOCH W. J. , HARMAN C. G. , O'BANNON L. S. 
Published: June 2006

The influence of the calculated oxide composition, batch composition, and application and firing techniques on the hardness, scratch resistance, resistance to attack by solutions of alkaline detergent materials, and other properties of glazes for vitrified institutional whiteware is discussed.The Knoop hardness of a reference glaze was increased by (a) the removal of lead, (b) the replacement of lead, potassium, or sodium oxides by lithia or by lithia and beryllia, (c) the addition of zinc oxide or lithia to the composition, (d) the substitution of beryllia for calcium oxide, and (e) the direct addition of calcium oxide to the glaze formulation. The resistance to attack by solutions of alkaline detergent materials was improved by (a) the substitution of lithia and beryllia for the oxides of lead, potassium, and sodium, (b) the substitution of zirconia for alumina, (c) the substitution of lithia for potassium oxide and sodium oxide, and (d) the addition of beryllia to the composition. In general, glazes that had outstanding resistance to abrasion, as determined by means of a sandblast test, failed to show a corresponding increase in resistance to attack by solutions of alkaline detergent materials. Of particular interest was the observation that the hardness of a glaze did not appear to be the factor governing the resistance of the glaze to scuffing in a simulated service test.
Some Physical Properties of Eight Refractory Oxides and Carbides
Authors: GANGLER JAMES J. 
Published: June 2006

An investigation of eight hot‐pressed refractory oxides and carbides for possible gas‐turbine application was undertaken. The properties, short‐time tensile strength at elevated temperatures, thermal‐shock resistance, coefficient of linear expansion, and density, were determined. The compositions of the ceramics included beryllium oxide, magnesium oxide, stabilized zirconia, zircon, boron carbide, 85% silicon carbide plus 15% boron carbide, titanium carbide, and zirconium carbide. The short‐time tensile strengths of these ceramics were determined at 1800° and 2200°F. Resistance to thermal shock was determined by rapid cooling in air to room temperature from 1800°, 2000°, 2200°, and 2400°F. The thermal‐expansion characteristics of these materials were studied from room temperature to 1100°F.Zirconium carbide was the strongest material at 2200°F. with a maximum short‐time tensile strength of 15,850 lb. per sq. in.; however, it exhibited extremely poor resistance to oxidation. Boron carbide had a short‐time tensile strength of 22,550 lb. per sq. in. at 1800°F., and was the strongest material at this temperature. Boron carbide also had very poor resistance to oxidation and was among the worst compositions investigated in its ability to resist fracture by thermal shock. The evaluation of strength of boron carbide at 2200°F. was unsuccessful because it fluxed with the grips. Titanium carbide had the best resistance to thermal shock, and had strengths of 15,850 lb. per sq. in. at 1800°F. and 9400 lb. per sq. in. at 2200°F. It was the most promising of the eight compositions investigated. Hot‐pressing of these eight highly refractory bodies indicated that a density of at least 93% of theoretical density could be obtained by this fabrication method.
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.
Phase Equilibria in the System BaTiO3‐SiO2
Authors: RASE D. E. , ROY RUSTUM 
Published: June 2006

The system BaTiO3–SiO2 is characterized by two congruently melting compounds and a compound having a subsolidus stability maximum. A barium analogue of the mineral sphene, BaTiSiO5, was shown to melt congruently at 1400°C, and BaTiSi2O7 melted congruently at 1250°C. The gem mineral benitoite (BaTiSi3O9) was synthesized hydrothermally and was shown to decompose below the solidus to form BaTi‐So2O7 and SiO2 when heated above 965°C, hydrothermally or above 1050°C, dry. Three eutectics in the system were determined: at 1245°C. and 70 mole % SiO2, at 1246°C. and 63% SiO2, and at 1260°C. and about 29% SiO2. Glasses with high refractive indices were obtained over a limited range of compositions. The cubic‐hexagonal transition temperature in barium titanate was raised sharply by small additions of silica. The maximum inversion temperature observed was 1575°C. and must have been due to limited solid solution of SiO2 in BaTiO3.SummaryThree intermediate compounds have been shown to exist in the system BaTiO3‐SiO2. The barium analogue of sphene, BaTiSiO5, melts congruently at 1400°C, and BaTiSi2O7 melts congruently at 1250°C. The compound BaTiSi3O9 (benitoite) was found to dissociate to form BaTiSi2O7 and SiO2 at 1050°C, under dry conditions and at 965°C, hydro‐thermally. This important gem mineral was synthesized from completely melted and quenched stoichiometric mixtures treated hydrothermally below 965°C, and at a water pressure of 5000 lb, per sq. in.There are three simple eutectics in the system: one between BaTiSi2O7 and SiO2 at 1245°C, and 70 mole % SiO2; one between BaTiSi2O7 and BaTiSiO5 at 1246°C, and 63% SiO2; and one between BaTiSiO5 and BaTiO3 at 1260°C, and about 29% SiO2.It was fairly easy to obtain glasses having refractive indices between 1.70 and 1.88 over a composition range of 50 to 75% Silica.The data pertaining to the cubic‐hexagonal transition in barium titanate were best explained on the basis of limited solid solution. As a result of the solid solution, the cubic‐hexagonal transition temperature is raised sharply from 1460°C. for the pure barium titanate to about 1575°C. by small additions of silica. The limits of solid solubility are approximately 8 and 4% SiO2 for the cubic and hexagonal forms, respectively.
A Tungsten Coil Furnace for High‐Temperature X‐Ray Diffraction Investigations
Authors: McKEAND I. J. , HURSH R. K. 
Published: June 2006

A furnace with a tungsten coil as the heating element has been designed and built for use with the X‐ray diffraction spectrometer in the study of phase changes and equilibria at high temperatures. Tests indicate that temperatures up to 2000°C. can be reached and maintained for long periods of time in a neutral atmosphere. Materials which are not readily affected by the tungsten vapors that are present can be heated successfully in this type of furnace.SummaryWith this furnace, samples may be heated to and held at temperatures up to 2000° C. while X‐ray spectrometer data are obtained. Phase changes and equilibrium conditions existing at temperatures considerably above those obtainable with Pt alloy elements and at different time intervals at constant temperatures can thus be readily and positively determined. It should be noted, however, that materials which are readily reduced by tungsten vapors cannot be satisfactorily heat‐treated in this particular type of furnace.
Ceramic Coatings for Nuclear Reactors A Progress Report
Authors: RICHMOND JOSEPH C. , LEFORT HENRY G. , WILLIAMS CHARLES N. , HARRISON WILLIAM N. 
Published: June 2006

Ceramic coatings were prepared from materials having low absorption coefficients for thermal neutrons. They were specifically designed for application to typical high‐temperature alloy parts for use in nuclear reactors. Best results were obtained with boron‐free coatings of the frit‐refractory type, in which a high‐barium frit containing small amounts of phosphate, beryllia, lime, zinc oxide, and titania was milled with additions of ceria or mixtures of chromic oxide and ceria. Coating compositions and test data are given.Summary and ConclusionsA total of 85 new frits and more than 200 new coatings were prepared and tested in the development of ceramic coatings for the protection of high‐temperature alloys against oxidation in air at elevated temperatures. The coatings which were designed especially for use in nuclear reactors, where only materials of low absorption coefficients for thermal neutrons can be used, may be suitable for more conventional purposes. The development work is still in progress, but the results to date may be summarized as follows:(1) Boron‐free frits have been developed and tested that have average neutron absorption coefficients in the range 0.15 to 0.50 barn, fritting temperatures of 2600°F. or below, and fiber‐deformation softening temperatures of 1450°F. or above.(2) The best frits developed to date are of the barium silicate type and contain small amounts of BeO, CaO, ZnO, and P2O5. Some of them also contain TiO2.(3) Coatings containing these frits, with admixtures of clay and various refractory oxides, have been developed and tested. The firing temperatures of the most promising of these coatings are in the range 1850° to 2250°F.(4) Of the refractory oxides used as mill additions in the coatings, best results were obtained with Cr2O3 and CeO2 and mixtures of the two.(5) The best ratio of frit to refractory oxide for all frits is 65 to 35 parts by weight.(6) Coatings were applied and adhered well to all the following alloys: types 309, 310, and 321 stainless steel, Inconel, Nichrome V, Stellite 25, and S‐816.(7) The protection given to the various coated alloy specimens varied with the composition of the alloys as well as with the composition of the coatings. Type 321 stainless steel was the most difficult to protect, and Nichrome V and Inconel were the easiest to protect. Type 310 stainless steel was relatively easy to protect.(8) The best evaluation of the degree of oxidation of a coated specimen during long‐time heating in air was obtained by microscopic comparison of metallographic sections of tested and untested coated specimens and determinations of the depth of external oxidation, maximum depth of stringer penetration, and number of stringers per inch of specimen.(9) The better coatings reduced greatly both the depth of stringer penetration and number of stringers per inch on type 310 stainless steel tested at 1900°F. for approximately 150 hours.
Calibration of Pyrometric Cones
Authors: BEERMAN H. P. 
Published: June 2006

Pyrometric cones produced by the Standard Pyrometric Cone Company (now known as The Edward Orton, Jr., Ceramic Foundation) were calibrated at the National Bureau of Standards in 1926. Cones available from the 1926 calibration were recalibrated, and new working standards were obtained by calibrating specimens of present production from the Orton Foundation. Heating rates of 150° and 60°C. per hour were used in determining the end points of a series of large cones, whereas a rate of 300°C. per hour was employed for the small cones through cone 12. The pyrometric cone equivalent (P.C.E.) series was calibrated and extended down to cone 12.
Rheological Factors for Bentonite Suspensions
Authors: GABRYSH W. F. , EYRING H. , LIN‐SEN PAN , GABRYSH A. F. 
Published: June 2006

The flow behavior of bentonite colloidal suspensions is given in terms of the stress‐strain relations with respect to variables of concentration, suspension medium, hydrogen‐ion concentration, temperature, and the successive application of shear stress. Repeated cycling (successive reruns of upcurve and downcurve) caused thixotropic hysteresis loops which decreased in size to a final constant and reproducible flow curve. A hysteresis loop did not appear for a mixture of less than 20 wt% bentonite and glycerin. The flow curves are discussed in terms of bondings in “cardhouse” and “blockhouse” models for dilute and concentrated suspensions respectively. Eyring's rate theory of viscosity is discussed briefly in terms of the well‐known generalized viscosity equationwhich was applied successfully to given flow curves. Physical and chemical characterizations are compared in terms of thixotropic flow models for aqueous, glycerol, and oil (Bentone grease) suspensions.
Lattice Defects in Tetragonal ZrO2
Authors: HOCH MICHAEL 
Published: June 2006

The activity of zirconium in the tetragonal ZrO2 phase was measured at 2200° to 2300°K as a function of composition by studying the reaction
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From the variation of the zirconium activity with composition, the pairwise interaction energy E11 between vacancies in the oxygen lattice was evaluated at ‐4.6 ± 1.0 kcal per mole.
Compressive Creep of Uranium Carbide
Authors: STELLRECHT D. E. , FARKAS M. S. , MOAK D. P. 
Published: June 2006

The compressive creep rates of slightly hyperstoichi‐ometric uranium carbide were determined in vacuum at 1200° to 1600°C and 3000 to 10,000 psi. The equation best describing the minimum creep rates of uranium carbide over this range is:é= 1.8 × 10−3σ3 exp (‐90,000/RT)
Kinetics of the Graphite‐Uranium Dioxide Reaction from 1400° to 1756°C
Authors: LINDEMER T. B. , ALLEN M. D. , LEITNAKER J. M. 
Published: June 2006

The reaction of microspheres of UOz with graphite was studied from 1400° to 1756°C. When a spherically symmetrical layer of carbide was produced around the UO2 core, only UC2 was formed, and the diffusion of oxygen through this layer was rate‐controlling. The Arrhenius relation for this system is kD= 21.0 exp(−90, 000/RT) cm2/sThe reaction of a geometrically nonsymmetrical configuration of UO2 and UC2 was also studied. Comparison of the reactions in the symmetrical and nonsymmetrical systems demonstrated that the kinetic behavior of the two systems is quite different and that the conversion in the nonsymmetrical system was 2 to 5 times faster. The importance of these observations to kinetic results reported in the literature for analogous systems is discussed.
Evaluation of Lattice Site and Valence of Mn and Fe in Polycrystalline PbTiO3 by Electron Spin Resonance and Thermogravimetry
Authors: HENNINGS D. , POMPLUN H. 
Published: June 2006

The oxides of Mn and Fe or combinations of La2O3 with these oxides were incorporated into PbTiO3 under defined thermodynamic conditions. The substitution reaction of these additives was examined gravimetrically. At low partial pressures of O2 and PbO vapor, Mn2+ and Fe2+ are formed at the A sites, and Mn3+ and Fe3+ enter both A and B sites. At higher partial pressures of PbO, Mn4+ is most probably formed at the B sites.The Mn2+, Mn4+, and Fe3+ were determined by ESR.
Strength and Toughness of a Ceramic Reinforced with Metal Wires
Authors: ZWISSLER J. G. , FINE M. E. , GROVES G. W. 
Published: June 2006

Composites consisting of fine stainless steel fibers 6, 12, or 25 μm in diameter in a matrix of wustite were prepared by hot‐pressing. The fracture stress (σF) of unnotched beams and the critical stress‐intensity factor (K1C) for crack initiation in notched beams were measured; both increased linearly with the volume fraction of fiber. These improvements were attributed partially to the action of yielding fibers which bridged the crack surfaces; plastic deformation of fibers at the crack tip was thought to play a role. Large increases (largest for the 25‐μm fibers) in the total work of fracture (γF) were attributed to the work done in fracturing crack‐bridging fibers. For long cracks bridged by fibers, over a substantial fraction of the crack, the critical applied stress intensity factor for further crack propagation increased strongly with increasing bridged crack length. The form of this increase could be accounted for by considering the negative stress intensity factor resulting from the closure forces exerted on the crack by the bridging fibers.Based on a thesis submitted by J. G. Zwissler for the Ph.D. degree at Northwestern University, Evanston, III., June 1976.Supported by the U. S. Office of Scientific Research, Office of Aerospace Research, Grant No. AF–AFOSR–73–2431 and by a fellowship from the International Nickel Co.
Fabrication of Reaction‐Sintered Sialon
Authors: WILLS R. R. , STEWART R. W. , WIMMER J. M. 
Published: June 2006

A factorial design experiment was conducted to determine the major parameters affecting the densification of mixtures having the composition (in mol%) 50 Si3N4, 25 A12O3, and 25 A1N. Improved densities of the resulting sialon were achieved using a longer milling time and SN‐502 Si3N4 powder. However, sialon samples prepared from the SN‐502 powder contained some of the X‐phase, whereas those fabricated from AME Si3N4 powder did not. This difference is considered to be due to the higher SiO2 content of the SN‐502 powder and its greater susceptibility to partial hydrolysis during the milling process. Reaction‐sintered sialon (97.2% theoretical density) fabricated using AME powder had a room‐temperature bend strength of 352MN/m2 (51,000 psi) and exhibited slow crack growth at 1300° and 1400°C. It is suggested that this is not an inherent property of sialon but is due to the presence of a calcium‐containing grain‐boundary phase, as in hot‐pressed Si3N4.
The Stability of Bredigite and Other Ca‐Mg Silicates
Authors: ESSENE ERIC 
Published: June 2006

The phase Ca7Mg(SiO4)4, bredigite, is chemically and structurally distinct from α‐Ca2SiO4. Experiments on its lower stability limit represent a synthesis limit which is not likely to be an equilibrium boundary. Equilibrium experiments place its upper stability limit at 1372°C and 98 kPa by the reaction
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The experimental data also require a second reaction
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at the same pressure and temperature and imply that two other reactions relating these phases are located near 1372°C and 98 kPa. Location of these four reactions around an invariant point in P‐T space shows that bredigite is on the low‐pressure side of the reactions.