bluuebunny/crossref_metadata_2025 huggingface dataset:
THERMOCHEMISTRY OF NORTH CAROLINA OLIVINE IN THE MANUFACTURE OF FORSTERITE REFRACTORIES*
Authors: Stone Robert L.
Published: October 2006

Abstract

A review of the properties of forsterite refractories is presented, and the causes of their failure are discussed. The main cause of failure is incomplete conversion of the impurities as shown by photomicrographs. The figures also show the several stages of breakdown of the crude olivine and the stages of conversion to forsterite as dependent upon temperature. The relation of the thermochemistry of the olivine to the manufacture of high‐grade forsterite refractories is given.
SOME SHEET‐IRON ENAMEL DEFECTS TRACEABLE TO THE BASE METAL OR METAL FORMING OPERATION*
Authors: Howe E. E.
Published: October 2006

Abstract

Cross sections through defects that were encountered in different plants were studied for the possible causes of the trouble. The defects that were traceable to some faulty condition in the iron are reported. It was found that hairlines, depressed lines, and blisters in the enamel may originate from some unusual condition in the metal before enameling.
APPLICATION AND USE OF THE IRWIN CONSISTOMETER IN ENAMEL SLIP CONTROL*
Authors: Frost L. J. , Hunt J. F.
Published: October 2006

Abstract

The Irwin consistometer is used to determine the effect of various clays, electrolytes, opacifiers, finenesses of grinding, time of aging, percentage of water addition, and increase of Epsom salts additions and temperatures on ground‐coat, cover‐coat, and acid‐resisting enamel slips. All results are represented in curve form on consistency graphs, which determine the relative yield value and mobility of the respective slips.
VANADIUM AS A GLASS COLORANT*
Authors: Weyl W. A. , Pincus A. G. , Badger A. E.
Published: October 2006

Abstract

Vanadium, as a glass colorant, acts much like chromium. Ordinarily it leads to green tints which are due to the superposition of the green of trivalent vanadium and the yellow of pentavalent vanadium. Large excess of alkali leads to the formation of colorless vanadates. Under special conditions, solarization may be used to develop the lavender color of bivalent vanadium. The effect of melting conditions and changes in the base glass composition on the colors is discussed.
A STUDY OF DRY‐PROCESS CAST‐IRON GROUND‐COAT ENAMELS*
Authors: Danielson R. R. , Koenigt J. H.
Published: October 2006

Abstract

This investigation covers a study of varying firing treatment of ground coats for cast iron and the resulting effect on the quality of adherence and the tendency to blister of dry‐process enamels. Five ground coats have been used, composed of one and two frits and with varying clay and flint additions at the mill. Data on the impact resistance of the enameled specimens obtained with a pendulum‐type impact tester are included. Conclusions are noted on some of the factors affecting firing range, and plans for further studies are outlined.
FUNCTIONS OF MINOR CONSTITUENTS IN COMMERCIAL SELENIUM RUBY BATCH*
Authors: Shively R. R. , Weyl W. A.
Published: October 2006

Abstract

In addition to the chemicals essential to the formation of the colorant, the nature of which is well established, successful commercial selenium ruby batches commonly contain a number of characteristic minor ingredients. These are zinc oxide, cryolite or other fluorine compounds, bone ash, and minute amounts of copper or nickel oxide.

Laboratory experiments are described which helped to establish the functions of these minor constituents. Owing to the extreme insolubility of copper and nickel sulfide in silicate melts, these compounds form at high temperatures and provide nuclei for the cadmium sulfoselenide which requires a lower temperature for its formation.

Bone ash, especially in combination with fluoride, leads to a very insoluble phase, apatite, which enhances the striking of the selenium ruby.

Formation of cadmium sulfoselenide will not take place at high temperatures. Introducing fluorine into a silicate glass facilitates molecular rearrangements because of the weaker forces exerted by this monovalent anion as compared with divalent oxygen ions. Fluorides increase the low‐temperature mobility of the glass and speed up the striking process.

The chief function of zinc oxide is to retain sulfur and selenium in the melt.

Alkali sulfoferrite and selenoferrite produce a red‐brown color, and their formation in glasses containing strong reducing agents, such as carbon, accounts for the deep color of some glasses containing only small amounts of cadmium sulfoselenide.
OXIDATION AND REDUCTION OF GLASSES BY MEANS OF ELECTROLYSIS*
Authors: Rindone G.E. , Marboe Evelyn C. , Weyl W. A.
Published: October 2006

Abstract

The existing need for better understanding and influencing the state of oxidation of colored glasses led to an investigation of the possibilities of oxidizing or reducing a glass melt by means of electrolysis. A method was developed for the electrolytic oxidations of molten glass in which the anodic and cathodic reaction zones were separated by means of a refractory diaphragm. Low‐melting alkali‐borate and alkali‐phosphate glasses containing a minor addition of colorant were electrolyzed using voltages up to 10 volts. It was found that electrolysis could be used to lower the “gas content” of a glass as well as to produce color changes.
STAINING OF GLASS CONTAINERS IN CONTACT WITH IRON*
Authors: Marboe Evelyn C. , Weyl W. A.
Published: October 2006

Abstract

A wet glass surface brought in contact with metallic iron acquires a brown stain which cannot be removed easily. This phenomenon was observed by the industry interested in the automatic washing of glass containers.

Iron in contact with wet glass surfaces will produce a chemically detectable contamination in one minute and a visible stain in ten minutes. This reaction of the glass surface with iron is galvanic in nature. Iron immersed in water sends positively charged ferrous ions into solution and leaves the metal with a negative charge. In the neighborhood of the iron, a negative electrical potential is established in the glass surface which helps to attract the positively charged ions from the solution. The stain is a result of the interaction of the glass surface and the iron ions, thus leading through oxidation to the formation of an insoluble, colored ferric hydrosilicate.

The staining can be prevented by reagents which (1) prohibit the corrosion of the iron, (2) block the active centers of the silica gel, and (3) produce anionic iron complexes.
TOPAZ AS AN ADMIXTURE IN REFRACTORY CONCRETE*
Authors: LoBAUGH Frank E.
Published: October 2006

Abstract

The effect of finely ground topaz on the fired strength of refractory concrete was investigated. A quantity of topaz equal in weight to the cement was added to the commonly used mixtures of calcium‐aluminate cement and grog. When fired at 1600°F. and above, the mixtures with topaz developed strengths three to six times those of the mixtures without topaz. Comparable fired strengths were obtained when potter's flint or silica flour was substituted for one half of the topaz admixture. A.S.T.M. standard refractory tests, with some variations, were made on different refractory concrete mixtures. Results of tests are reported and applications where use of topaz admixture is advantageous are suggested.
PROPERTIES OF BARIUM‐STRONTIUM TITANATE DIELECTRICS*
Authors: Bunting E. N. , Shelton G. R. , Creamer A. S.
Published: October 2006

Abstract

The results on barium‐strontium titanates are given for heat‐treatment, absorption, shrinkage, thermal expansion, dielectric constant, K, at minus 60° to 85°C. and also for Q (the reciprocal of the power factor) at 25°C. for frequencies of 50 kc. per sec. to 20 mc. per sec. A few measurements of K and Q were made at 3000 mc. per sec. Specimens with an absorption of less than 0.l% matured at 1250° to 1430°C. K values ranged from 34 for BaO:4TiO2 to several thousand for specimens with compositions on the BaTiO3‐SrTiO3 join. The BaO: 5TiO2 specimens were unique in that their temperature coefficient of K was practically zero. O values ranged from 50 to 100 for test pieces containing more than 40% of BaO and from 400 to 10,000 for those with less than 40% of BaO. K values did not change appreciably with frequency. Linear thermal expansions (between 25° and 700°C.) ranged from 0.6 to 0.84%. Many of these specimens could be used in radio equipment.
EFFECT OF MAGNESIA AND ALUMINA ON RATE OF CRYSTAL GROWTH IN SOME SODA‐LIME‐SILICA GLASSES*
Authors: Swift Howard R.
Published: October 2006

Abstract

Measurements were made of the rates of crystal growth in a series of glasses with 74% SiO2, 16% Na2O, and 10% (CaO + MgO), the MgO replacing the CaO in 2% steps; and in a series of glasses with 17% Na2O, 12% CaO, and 71% (SiO2+ Al2O3), the alumina replacing the silica in 2% steps up to 8% Al2O3. A study was also made of the rate of crystal solution in the series with variable alumina. The results are explained qualitatively by considering the viscosity and crystallization temperature changes of the glasses as the composition varied.

The substitution of MgO for CaO to the composition with the minimum liquidus decreased the maximum rate of crystal growth of cristobalite (primary phase) and devitrite (secondary phase) and further substitutions increased the rate of crystal growth of diopside and Na2O·2MgO·6SiO2. Substitution of Al2O3 for SiO2, decreased the maximum rate of crystal growth of devitrite, and substitutions of more than 4% of Al2O3 increased the rate of crystal growth of wollastonite.
DEVELOPMENT OF ZIRCONIA RESISTANT TO THERMAL SHOCK*
Authors: Curtis Carl E.
Published: October 2006

Abstract

The effects on the crystal stabilization and other properties of pure zirconia were determined for additions of CaO, MgO, BeO, ThO2, and CeO2 in binary and ternary combinations. Complete stabilization was attained with the following compositions (in mol. %): 10 to 20 CaO, 14 MgO, 26 CeO2, 10 CaO + 5 ThO2, 10 CaO + 5 BeO, or 2 to 7 CaO + 4 to 6 to MgO. Cerium oxide produced partial stabilization, but BeO and ThO2 used alone were ineffective at 1927°C. Some strong, dense bodies were found which had good resistance to thermal shock, namely, those containing (mol. %) 8 to 12 CaO, 6.7 CaO + 3.7 MgO, or 2.3 CaO + 6.4 MgO; all of these compositions still had a small amount of inversion present.

This small inversion may be necessary for high resistance to thermal shock in ZrO2 ware because (a) the over‐all thermal expansion is then small and gradual and (b) with complete elimination of inversion, the expansion is large since the expansion curve is a straight line and the coefficient of expansion is rather high, 11 to 12 × 10‐6.
FABRICATION OF THIN CERAMIC SHEETS FOR CAPACITORS*
Authors: Howatt G. N. , Breckenridge R. G. , Brownlow J. M.
Published: October 2006

Abstract

A method for the fabrication of thin ceramic sheets for use as capacitor dielectrics is described. Electrical tests indicate that titanium dioxide and various titanate sheets so prepared are desirable for such applications.

A machine is described which extrudes a ceramic slip with a resin binder on a moving belt. The thin sheet is strong enough when dry to be stripped off and cut or punched to any desired flat shape and fired satisfactorily. The electrical properties of the material so produced have been determined and the assembly of the sheets into capacitors is discussed.
PURE BERYLLIUM OXIDE AS A REFRACTORY*
Authors: Norton F. H.
Published: October 2006

Abstract

The development of a pure BeO refractory is described, using pure Be(OH)2 as the starting material. The hydroxide is calcined at 1200° (low) to 1800°C. (high), depending on the crystal size desired. The calcine is ball milled wet in a steel mill and cast at pH 4.5 to 5.0, or the powder may be dried and mixed with 14% Carbowax 4000 added as a water solution for dry pressing at 20,000 to 30,000 lb. per sq. in. The pressed product is vitreous when fired at 1800°C. but is also volatile at that temperature.
LOW‐LEAD, BRIGHT OPAQUE GLAZES AT CONES 08 TO 06*
Authors: Danielson R. R.
Published: October 2006

Abstract

This investigation covered several systematic fields of opaque fritted glazes for cones 08 to 06 (1733° to 1841°F.) in which lead oxide was replaced by barium, strontium, and zinc oxides. All glaze ingredients except the kaolin and the Ultrox zirconium opacifier were incorporated in the frits. Glazes of low‐lead content as well as some lead‐free compositions were obtained which possessed excellent gloss and opacity on wall tile of low and of medium tale content. Barium oxide was the best substitute for lead oxide from the standpoint of gloss, although moderate amounts of strontium and zinc oxides can be used to advantage. The whitest and most opaque glazes were obtained with the use of zinc oxide.
BLACK LIGHT, FLUORESCENCE, AND CERAMICS*
Authors: Arrance Frank C.
Published: October 2006

Abstract

The sources of ultraviolet energy, the equipment available, and its application to the ceramic field are discussed. Examples of the use of fluorescent techniques in mining and prospecting, laboratory control, inspection, and research are given, and some commercial applications are discussed.
TRANSVERSE‐STRENGTH MACHINE BASED ON CHAINOMATIC PRINCIPLE*
Authors: Amberg C. R
Published: October 2006

Abstract

A new design for a cross‐breaking machine is described. The machine is well adapted for breaking bars of 1‐in. cross section in the ranges of strength encountered in both un‐fired and fired bars of ceramic compositions. The loading is practically vibrationless. The machine has proved a time saver for testing materials such as raw clay bars.
REACTION OF DIFFERENT CLAY MINERALS WITH SOME ORGANIC CATIONS*
Authors: Grim R. E. , Asllaway W. H. , Cuthbert F. L.
Published: October 2006

Abstract

Selected pure samples of kaolinite, illite, and montmorillonite were washed with 0.05 N HCl until free from replaceable bases, washed with water or methanol, and then reacted with sufficient KOH to saturate the exchange complex with K+ at pH 7. These K clays were given variable dosages of n‐butylamine acetate, dodecylamine acetate, and ethyldimethyloctadecenylammonium bromide. The conclusions are as follows: (1) additions of amines or other organic cations in amounts less than equivalent to the base‐exchange capacity of the clay are rather. completely adsorbed in base‐exchange reactions; amounts of large organic cations added in excess of the base‐exchange capacity of the clay tend to be adsorbed by a different reaction, probably dependent on the action of the van der Waals' forces; and (2) the ability of clays to absorb water is greatly reduced by treating the‘clays with certain compounds that furnish a large organic cation.
METHOD FOR DETERMINING TENSILE PROPERTIES OF REFRACTORY MATERIALS AT ELEVATED TEMPERATURES*
Authors: Bressman Joseph R.
Published: October 2006

Abstract

Equipment for testing ceramic materials to temperatures of 2000°F. was developed, and a method was devised for evaluating the bending stresses introduced by the test equipment. With this equipment, the tensile strength, stress‐to‐rupture characteristics, and modulus of elasticity of a sillimanite refractory were investigated at the Cleveland Laboratory of the National Advisory Committee for Aeronautics. The tensile strength varied from a minimum of 8000 lb. per sq. in. at 500°F. to a maximum of 19,000 lb. per sq. in. at 1800°F. Heat‐treating the tensile specimens for one half hour at 1800°F. increased the tensile strength 35% at room temperature and 70% at 500°F. No increase in strength was noted at or above 1400°F. The stress‐to‐rupture in 1000 hours at 1600°F. was 8500 lb. per sq. in. The modulus of elasticity at room temperature was 20.3 × 106.
TRANSLUCENCY METER FOR USE IN WHITEWARE RESEARCH*
Authors: Haldy N. L. , Wright J. H. , Todd F. C.
Published: October 2006

Abstract

A photoelectric light meter, based on a design by RCA, was developed for a research tool in investigations on whiteware, particularly chinaware. Since its development, it has also found use in work on enamels and on glass. The meter is described in this paper and results obtained with it on both laboratory‐prepared and commercially prepared chinaware are given. In addition to use in research, it may be of interest to chinaware manufacturers as a control instrument.

The chinaware bodies investigated followed Lambert's exponential law of light absorption.

The necessity for obtaining translucency data on pieces of the same thickness, even for relative values, is indicated.
ALUMINA‐SILICA RELATIONSHIP IN GLASS*
Authors: Safford Hurd W. , Silverman Alexander
Published: October 2006

Abstract

Assuming from a consideration of silicate minerals that aluminum should replace silicon in silicates, the authors investigated the system Na2O‐CaO‐SiO2‐Al2O3. Densities and refractive indices have been determined and molecular refractions have been calculated. Partial molecular refractivities of Al2O3 indicate a coordination number of 4 for aluminum and deviate appreciably from values for compounds in which aluminum has a coordination number of 6. Interionic distances have been calculated for Si—O and Al—O. As a result of these studies, it is concluded that the aluminum atom isomorphously replaces the silicon atom in the random fetrahedral network. With this replacement, Ca++ can increasingly replace Na+ in the interstices of the open structure.
MICROSCOPIC AND X‐RAY INVESTIGATION OF SOME STEATITE BODIES*
Authors: Rigterink M. D.
Published: October 2006

Abstract

Microscopic, and X‐ray examinations of a series of steatite compositions reveal that the body having the best dielectric properties Also has the simplest and most homogeneous physical structure. It is believed that the attainment of similar physical structures in other ceramic bodies will lead to improvements in dielectric properties.

This empirical finding is in accordance with present theories of conduction in crystals. It depends on the contribution to conductivity and dielectric loss made by imperfections of crystal structure. However, even in homogeneous materials, alkaline earth ions tend to cause less conduction under like conditions than alkali ions, and there are high‐dielectric constant materials like the titanates which, though homogeneous and pure, have a high loss.
DEVELOPMENT OF HARD GLASSES*
Authors: Pavlish A. E. , Mockrin I.
Published: October 2006

Abstract

This paper covers a phase of the work which was carried out for the Office of Production Research and Development of the War Production Board on the development of glasses of increased hardness for use as instrument bearings. A literature survey was made and a study started on the development of hard glasses for use in the manufacture of glass bearings. The data are of interest since information on the effects of a number of these oxides on the hardness of glass either have not been published previously or, in former studies, the amounts of oxides were not so large as those used in this work.

Practically all of the work reported here was done either in the alumina‐silica‐boric oxide‐calcium oxide system or on glasses derived from this system by substitution of various oxides, chiefly for silica. The Knoop hardness numbers of the glasses are reported. Data were not obtained on the working properties of the glasses described herein.

In addition to the footnote references, a comprehensive bibliography is given at the end of the paper.
EFFECT OF COMPOSITION ON PROPERTIES OF TITANIUM ENAMELS*
Authors: Friedberg A. L. , Petersen F. A. , Andrews A. I.
Published: October 2006

Abstract

The development of a superopaque, acid‐resistant titanium enamel is described. Different components of the batch were varied systematically and the properties, such as reflectance, color, flow, gloss, and acid resistance, were determined. Variations in composition, reflectance curves, and spectrophotometer curves are given for all of the enamels investigated. The stability of this type of enamel during firing and smelting was also studied.

Spectrophotometric analyses of this type of enamel show a characteristic low reflectance in the short‐wave length region of the visible spectrum, differing in this respect from superopaque antimony and zirconia enamels. Additions of as much as 0.5% Fe2O3 and 0.2% V2O5 to the titanium enamel did not cause any appreciable variations in color. Although some differences in the spectrophotometer curves were noted over the field of enamels investigated, the only major change in color occurred when minute amounts of Cr2O3 were present.

X‐ray diffraction patterns of enamels show that rutile crystals in most cases, or sometimes anatase, are the crystals causing opacity.
COMPARISON OF VARIOUS ANTIMONATES AS OPACIFIERS IN DRY‐PROCESS ENAMELS FOR CAST IRON*
Authors: Coffeen William W.
Published: October 2006

Abstract

Antimonates of potassium, lithium, barium, calcium, magnesium, strontium, zinc, aluminum, lead, and tin were substituted for sodium antimonate in an acid‐resisting dry‐process enamel for cast iron. The sodium antimonate content of this high‐lead enamel was also varied to permit comparisons of all antimonates with sodium antimonate, as a standard, on an equivalent antimony pentoxide basis. Reflectance, color, and acid‐resistance data on all enamels are presented.

A number of the antimonates were compared as replacements for sodium antimonate in non‐acid‐resisting enamels of the lead‐bearing and leadless types. Reflectance and color data are given.

In acid‐resisting enamels, antimonates of potassium and barium compared reasonably well with sodium antimonate in opacifying power without introducing objectionable colors. Barium antimonate also produced improved acid resistance.

In non‐acid‐resisting enamels, only barium antimonate produced results approaching sodium antimonate in both leadless and lead‐bearing types.

The data indicate that the antimonates do not contribute equally to opacity and color, even though all contain antimony in pentavalent form. Barium antimonate most closely approaches sodium antimonate in effectiveness. The behavior of the antimonates suggests an explanation for the variations often encountered with antimony oxide enamels.
WEATHER RESISTANCE OF PORCELAIN ENAMELS EXPOSED FOR SEVEN YEARS*
Authors: Harrison William N. , Moore Dwight G.
Published: October 2006

Abstract

A study of the weather resistance of porcelain enameled architectural panels was begun at the National Bureau of Standards in 1939. The study involved 864 one‐foot‐square panels and an equal number of 4‐ by 6‐in. laboratory specimens. A previous report (1942) gave the results after one year of exposure. The present paper describes the condition of the panels after seven years of weathering in Washington, D. C., St. Louis, Mo., Lakeland, Fla., and Atlantic City, N. J.

The results of the seven‐year inspection showed good correlation between the acid resistance of enamels and their resistance to weathering. When initial coverage was complete and no mechanical damage had occurred, protection of the metal by the enamel for all specimens was unimpaired after seven years. Colored enamels faded only on panels having poor acid resistance.
ONE‐FIRE WHITE ENAMELS*
Authors: King Burnham W. , Stull C. Wesley
Published: October 2006

Abstract

The problems encountered in the use of one‐fire white enamels are reviewed. The reactions and changes taking place during the firing of an enamel are described in some detail and are illustrated by photomicrographs of a one‐fire white enamel. Photomicrographs are also shown of various white enamels fired directly on steel. Several possible steel and enamel combinations are considered. Data are given regarding the reflectance and chemical resistance of various white enamels fired at 1300° and 1500°F. The importance of the end use of the enameled article is emphasized.
CORRELATION OF WEATHER RESISTANCE OF PORCELAIN ENAMELS WITH CHEMICAL‐TEST DATA*
Authors: Sweo B. J.
Published: October 2006

Abstract

Twenty‐one enameled specimens were exposed for approximately tea months in an industrial area arid were graded visually by ten observers for weather resistance based on appearance change as compared with an unexposed standard. Weight‐loss data were obtained on exposure to boiling solutions of (1) distilled water, (2) 6% citric acid, and (3) 5% sodium pyrophosphate. Acid‐resistance data were obtained by employing the Porcelain Enamel Institute research test. These data were correlated with the weather‐resistance gradings. Loss of weight on exposure to boiling 6%; citric acid appeared to give the best indication of weather resistance.
NOTCH SENSITIVITY AND LOW‐TEMPERATURE SPALLING OF FIRE‐CLAY REFRACTORIES*
Authors: Rose Ralph , Bradley† R. S.
Published: October 2006

Abstract

Attempts were made to correlate the physical properties of fire‐clay refractories with the phenomenon of low‐temperature spalling. A method of considerable promise was developed in which the relative flexural strength of fire‐clay refractories at 1500°F., in the notched and unnotched condition, indicated the resistance of these bodies to low‐temperature spalling. No purely mathematical relationship between the physical properties and low‐temperature spalling characteristics appeared to be valid.
FUNDAMENTAL STUDY, AND EQUIPMENT FOR SINTERING AND TESTING OF CERMET BODIES: IV, DEVELOPING AND TESTING EQUIPMENT*
Authors: Shevlin T. S. , Blackburn A. R.
Published: October 2006

Abstract

A relatively large molybdenum‐wound resistor furnace, a diamond‐wheel rod‐grinding machine, a tensile stress‐rupture machine, and thermal‐expansion equipment used for the development and testing of cermets are described. All are additions to equipment described previously, having been designed and used successfully during the past year.
FUNDAMENTAL FACTORS INFLUENCING EFFLORESCENCE OF CLAY PRODUCTS*
Authors: Brownell W. E.
Published: October 2006

Abstract

Samples of shale from the Sew York State Clay and Shale Survey were selected for the study of efflorescence. Some of the shales had no tendency to effloresce after firing whereas others produced slight to heavy efflorescence. A satisfactory means of qualitative and quantitative measurement of soluble salt content was applied to the raw and fired shale specimens. These analyses provided an indication of the liability to effloresce. The causes of the development of soluble salts in these materials were traced. It was found that soluble salts were formed in the ceramic body during firing by reaction with SO2 gas and by solid‐state reactions involving SO4 ions. The presence of insoluble mineral sulfides and sulfur‐bearing organic compounds in the raw materials were important causes of sulfate formation. The mechanism of sulfate formation was studied. Procedures for the prevention of efflorescence are discussed.
FLUID‐FLOW STUDY OF POROUS GLASS*
Authors: Schwertz F. A.
Published: October 2006

Abstract

The rate of penetration of air, water, and acetone through porous Vycor‐brand glass is used to calculate the specific surface area, the average pore diameter, and the pore‐population density of this material. The results are in approximate agreement with those obtained using the Brunauer‐Emmett‐Teller adsorption technique.
SLIP CASTING OF ALUMINUM OXIDE*
Authors: Hauth W. E.
Published: October 2006

Abstract

Fused alumina, after being subjected to ball milling and acid treatment, may be suspended in water to form a slip. Deflocculation is obtained by the addition of the proper amount and type of either an acid or a base. Both drain and solid castings can be produced successfully from acidic or basic slips. The casting behavior of the slips and the properties of the cast pieces are summarized for variations in pH and specific gravity, the range of pH being 3.00 to 12.50 and the range of specific gravity, 2.60 to 3.00. Although no extensive investigation of the firing behavior was made, sufficient firing was done to indicate that no special techniques are required.
EFFECT OF RINSING ON CHEMICAL DURABILITY OF A CONTAINER GLASS*
Authors: Lyon K. C.
Published: October 2006

Abstract

New soda‐dolomite lime‐silica glass bottles were rinsed with 0.001 N solutions of several chlorides, sulfates, and nitrates. The bottles were then rinsed with doubly distilled water and subjected to an autoclave test for alkali extraction by water. Of the compounds tested, those of copper caused the greatest reduction in alkali extraction. The effects of concentration and duration of treatment with copper chloride solution were studied.
THE WORD “CERAMIC”*
Authors: Russell Ralston , Watts Arthur S.
Published: October 2006

Absrract

A case is presented for wider acceptance of the word “ceramic” as a noun in the singular sense to complement the more common use of the word as a plural noun or singular adjective.
THE SYSTEM BaO–B2O3*
Authors: Levin Ernest M. , McMurdie Howard F.
Published: October 2006

Abstract

A phase‐equilibrium diagram of the system BaO–B2O3 has been constructed from data obtained essentially by the quenching method. Four congruently melting compounds were identified: BaO·4B2O3, melting at 879 ± 5°C.; BaO·2B2O3, melting at 900 · 5°C.; BaO·B2O3, melting at 1095 ± 5°C.; and 3BaO·B2O3, melting at 1383 ± 5°C. Some optical properties of these compounds were determined with the petrographic microscope, and X‐ray diffraction data suitable for their identification were obtained. Barium metaborate, BaO·B2O3, showed an inversion occurring between 100° and 400°C. Mixtures containing less than 30% BaO were found to separate, on fusion, into two liquid layers; one layer contained 30% BaO and the other was nearly pure B2O3. A curve showing indices of refraction of the quenched glasses is presented.
CASTING CHARACTERISTICS OF CLAYS: II, INFLUENCE OF SLIP PREPARATION METHODS ON PROPERTIÉS OF CAST WARE*
Authors: Russell R. , Mohr W. C. , Rice H. H.
Published: October 2006

Abstract

Data are presented to indicate the influence of slip preparation methods on the dry and fired properties of cast high‐voltage electrical porcelain. The factors investigated include length of mixing period, sequence of electrolyte addition, aging, blunging versus ball milling, micropulverizing of constituents before blunging, filtering and reblunging application of vacuum to slip, and use of heated water. Wet ball milling influenced the properties most markedly, yielding ware with improved dry and fired strengths and lower fired absorption. Further investigation of the wet ball‐milling preparation method indicated that (1) increased dry strength is due primarily to the milling of the clay or' plastic constituents, (2) increased fired strength is obtained by the milling of both plastic and nonplastic constituents, and (3) lower fired absorption is due primarily to the milling of feldspar and flint.
EFFECT OF SODA, POTASH, AND LITHIA ON PHYSICAL PROPERTIES OF A TITANIA COVER ENAMEL*
Authors: Cook Ralph L. , Essenpreis James F.
Published: October 2006

Abstract

The effect of the substitution of small amounts of lithia and variations in the amount and ratio of alkalis on the properties of a titania cover enamel was investigated. The flow characteristics, acid resistance, reflectance, gloss, and color of the enamels were determined. In addition, the recrystallization characteristics of several of the titanis cover enamels were studied. When Li2O was substituted for K2O, reflectance increased, fluidity decreased, and the color shifted toward the yellow‐white with no noticeable effect on gloss or acid resistance. When Li2O was substituted for Na2O, no appreciable improvements were noted in the properties of the enamels. Replacement of 1 part K2O by Li2O resulted in more complete recrystallization.
FUNDAMENTAL STUDY OF CLAY: IX, INFLUENCE OF PARTICLE SHAPE ON PROPERTIES OF SUSPENSIONS*
Authors: Couchanour L. W. , Sorton F. H.
Published: October 2006

Abstract

The flow properties of suspensions containing monodisperse particles of muscovite, kaolinite, halloysite, and orthoclase were measured at various concentrations to determine the influence of particle shape. It was found that the particle shape had a considerable effect in dispersed suspensions, the more isometric particles yielding the lower viscosity. Particle shape made no difference in flocced suspensions.
IMPROVED MOUNT FOR POWDERED SPECIMENS USED ON THE GEIGER‐COUNTER X‐RAY SPECTROMETER*
Authors: McCreery George L.
Published: October 2006

Abstract

Preparation of powdered specimens to achieve a high degree of random orientation and improved uniformity is described and illustrated. Patterns obtained on some commonly encountered ceramic minerals are included.
EVALUATING ADHERENCE OF BLUE SHEET‐IRON GROUND COATS*
Authors: McLauchlin J. L.
Published: October 2006

Abstract

Reflectance measurements are used to evaluate the adherence of blue ground coats on sheet‐iron plates which have been tested by the drop‐hammer impact machine. The values obtained show good correlation with visual estimations of adherence of enamel on steel with and without nickel flashing.
EVALUATION OF SURFACE FINISH OF PORCELAIN ENAMELS BY A REPLICA METHOD*
Authors: Richmond J. C. , Francisco A. C.
Published: October 2006

Abstract

A technique for making ethyl cellulose replicas of enameled and other surfaces is described. Photographic prints of a number of replicas made without the use of negatives are shown, and methods of analyzing the replicas are discussed.

The haze of rep1icas was used to evaluate 25 enamels abraded in the standard P.E.I. surface‐abrasion test. Graphs are shown comparing these ratings with those obtained by (1) the standard method, (2) visual estimates of the abrasion as seen on the enameled specimens, and (3) visual estimates of the abrasion as seen in the replicas. The haze‐of‐replica method appears to offer advantages for evaluating the amount of abrasion.
QUANTITATIVE ANALYSIS OF CUBIC AND MONOCLINIC ZIRCONIA BY X‐RAY DIFFRACTION*
Authors: Duwez Pol , Odell Francis
Published: October 2006

Abstract

The X‐ray diffraction technique presents a simple method for the quantitative analysis of mixtures of polymorphic forms of the same substance. The X‐ray spectrometer provides a rapid means for such work. In the case of zirconia, the relative intensities of the cubic (111) reflection and the monoclinic (111) and (111) reflections are related to the proportions of each form present. Details of the specimen preparation technique, instrument operation, and specific calibration curves are included.
SYSTEMATIC STUDY OF EFFECT OF OXIDE CONSTITUENTS ON VISCOSITY OF SILICATE GLASSES AT ANNEALING TEMPERATURES*
Authors: Poole James P. , Gensamer Maxwell
Published: October 2006

Abstract

Experimental low‐temperature viscosity data obtained by the fiber‐elongation method are presented for simple three‐ and four‐component alkali‐alkaline earth‐alumina silicate glasses. In this study, soda, potash, calcia, magnesia, strontia, baria, and alumina were systematically substituted molecularly for silica and each other. A wide range of compositions was studied, including most commercial silicate glasses. Factors, formulas, and charts derived from experimental data are presented that predict the viscosities of soda‐lime‐alumina silicate glasses within about 1%.
LOW‐TEMPERATURE VISCOSITY OF ALKALI SILICATE GLASSES*
Authors: Poole James P.
Published: October 2006

Abstract

Using an improved technique, precision measurements of viscosities in the annealing range of temperature were made on sodium, potassium, and sodium‐potassium silicate glasses containing from 10 to 40 mol % alkali. The viscosities of certain of those glasses that contain both Na2O and K2O reach minima, and the temperature coefficients of viscosity, which are nearly equal for the Na2O and the K2O glasses, become considerably smaller. These conditions may explain the practical advantages of certain glasses containing both Na2O and K2O.
AN EXPERIMENTAL GLASSMELTING FURNACE*
Authors: Poole James P.
Published: October 2006

Abstract

The design of a large‐scale glassmelting furnace with a rotating hearth is presented, along with a discussion of firing procedures and the techniques used to determine melting and fining times that are comparable to those obtained in the operation of a continuous tank furnace.
Temperature and Orientation Dependence of Plastic Deformation in GaAs Single Crystals Doped with Si, Cr, or Zn
Authors: SWAMINATHAN V. , COPLEY S. M.
Published: October 2006

Stress‐strain curves are presented for Si‐doped GaAs single crystals deformed in compression parallel to <100> and <111> at temperatures ranging from 250° to 550°C. In both orientations, slip occurs only on {111} <1&1bar;0>. Repeated‐yielding experiments on GaAs crystals, both undoped and doped with Si, Cr, or Zn, indicate that Si‐doped crystals (n‐type) have a greater yield stress than undoped crystals, that undoped crystals have a greater yield stress than Zn‐doped crystals p‐type), and that Cr doping does not significantly affect the yield stress. Extensive crack formation resulting from deformation was not observed. Compression specimens normally failed by breaking into several columnar fragments with their long dimension parallel to the stress axis.
Use of Thermoelectronic Emission for Studying Point Defects in Refractory Oxides
Authors: RIFFLET J. C. , ODIER P. , ANTHONY A. M. , LOUP J. P.
Published: October 2006

The thermoelectronic emission of refractory oxides in equilibrium with O2 pressures from 10−6 to 10−11 atm at T > 1200°K is controlled not by chemisorption but by point defects present in the oxide. The effect of gases such as CO, CO2, and N2 was investigated. Analysis of the emission results for ZrO2 and Y2O3, compared with their electrical conductivities, indicates the presence of anti‐Frenkel disorder in these materials. Thus, high‐temperature thermoelectronic emission as a function of O2 pressure can be used to study point defects in refractory oxides.
Creep Deformation of Reaction‐Sintered Silicon Nitrides
Authors: DIN SALAH UD , NICHOLSON PATRICK S.
Published: October 2006

The steady‐state creep behavior of reaction‐bonded silicon nitride, prepared by slip casting and injection molding, was examined in 4point bending with stresses ranging from 10,000 to 20,000 psi at temperatures from 1200° to 1450°C. Creep rates were proportional to the 1.4 power of the stress. The creep process exhibited an activation energy of 130±5 kcal/mol. The microstructure of deformed specimens, which was revealed by transmission and scanning electron microscopy, contained triple‐point voids suggesting that the rate‐controlling mechanism of creep is grain‐boundary sliding.
Stable and Metastable Equilibria in the System SiO2‐Al2O3
Authors: AKSAF İ. A. , PASK J. A.
Published: October 2006

Concentration profiles of Al2O3 in diffusion couples made from sapphire and fused silica were used to determine the stable equilibrium phase diagram of the system SiO2‐Al2O3. The intermediate compound mullite, 3Al2O3· 2SiO2, melts incongruently at 1828°± 10°C; its stable solid‐solution region ranges from 70.5 to 74.0 wt% Al2O3 below 1753°C and from 71.6 to 74.0 wt% at 1813°C. The microstructures of diffusion zones and heat‐treated specimens also indicate the incongruency of mullite. Additional information is given for 3 metastable systems: SiO2‐Al2O3, in the absence of mullite, SiO2‐“ordered”‐mullite in the absence of alumina, and SiO2‐“disordered”‐mullite in the absence of alumina. Under metastable conditions, ordered mullite melts congruently at = 1880°C and its solid‐solution range extends up to = 77 wt% Al2O3. The solid‐solution range of disordered mullite extends to ∼ 83 wt% Al2O3 with an estimated congruent melting temperature of ∼ 1900°C. The existence of metastable systems is associated with superheating of mullite above the incongruent melting temperature and with nucleation of alumina and mullite in supercooled aluminum‐silicate liquids.
Failure Prediction of the Thermal Fatigue of Silicon Nitride
Authors: HASSELMAN D. P. H. , CHEN E. P. , AMMANN C. L. , DOHERTY J. E. , NESSLER C. G.
Published: October 2006

Slow crack growth data were used to predict the thermal fatigue life of silicon nitride parts subjected to the cyclic thermal environment of a turbine engine. For this purpose, a computer program was devised which numerically calculates the extent of slow crack growth for each successive thermal cycle until catastrophic failure occurs. Reasonable agreement was found between predicted and experimental fatigue life. Discrepancies were attributed to uncertainties in the values for the property data required for the fatigue calculations, as well as to statistical aspects of brittle fracture. Results of failure predictions for materials having flaw depths smaller than those encountered in the present specimens suggest that silicon nitride can be made more resistant to thermal fatigue by minimizing the amount of viscous grain‐boundary phase, which is responsible for slow crack growth.
Effect of Moisture Content on Strength and Strain Energy Release Rate of Cement Mortar
Authors: GLUCKLICH JOSEPH , KORIN URI
Published: October 2006

Specimens with small cross sections, dried in vacuum desiccators, were used to determine the influence of moisture content on the strength of cement mortar. Bending and compressive strengths, strain energy release rate, elastic modulus, and shrinkage were measured. As expected, strength increased as the moisture content decreased; the effect was greatest at the lower moisture contents (provided drying conditions did not cause cracking). The influence of moisture on the surface energy of the gel solids and on the elastic modulus was investigated. Because surface energy is difficult to measure, the strain energy release rate was determined instead, and these parameters were assumed to be covariants with moisture. The strain energy release rate increased sharply when the monomolecular water layer on the gel solids began to evaporate. It is suggested that moisture influences strength through its effect on 2 mutually independent components, i.e. the strain energy release rate and the elastic modulus. Using equations of fracture mechanics, with typical values assumed for the depth of surface cracks and the width of body cracks, a fairly good correlation was found between theory and experimental results.
Transport of Pb Ions at the Interface Between Silicate Glass and Molten Lead
Authors: MATOUŠEK JOSEF
Published: October 2006

The influence of an external dc electric field on the Pb content near the interface between float glass and molten Pb was studied at 500°C. The diffusion coefficient and velocity of Pb ions in the external electric field were determined, and the theoretical time dependence of Pb content in the glass was calculated. A theoretical model of ion transport phenomena in the system is suggested.
Oxidation of 6H‐α Silicon Carbide Platelets
Authors: HARRIS RICHARD C. A.
Published: October 2006

Oxidation on the 2 crystal faces of SiC platelets was studied. The oxidation of the C face followed a simple parabolic law and was oxide‐diffusion controlled, whereas that of the opposite crystal face exhibited a linear growth rate which was surface‐reaction controlled. Previous investigators, who studied the oxidation of Sic by measuring weight change, found that the oxidation rate follows a simple parabolic law. At high temperatures and long reaction times, there is an increase in the oxidation rate which has previously been attributed to a change in the state of the oxide. The present investigation, however, indicates that this change occurs as the linear oxidation rate becomes dominant.
Strength of Glass Rods in Polar and Nonpolar Liquids
Authors: McCAMMOND D. , NEUMANN A. W. , NATARAJAN N.
Published: October 2006

The failure strengths of soda‐lime glass rods exposed to 9 liquids with polarities from 30.9 to 63.1 kcal/mol were determined experimentally in flexure. The fracture strength clearly decreased with increasing polarity. The necessity of maintaining a high degree of purity in the environmental fluids to obtain meaningful results was illustrated by tests in which controlled amounts of a highly polar liquid (methanol) were introduced into pure n‐hexane. Traces as small as 0.004% reduced the strength significantly whereas a 0.05% addition reduced it to that in pure methanol.
Edge‐Defined Film‐Fed Growth of β‐Alumina and Mg‐Substituted β‐Alumina
Authors: MORRISON A. D. , STORMONT R. W. , COCKS F. H.
Published: October 2006

High Na vapor pressure, peritectic decomposition, and high reactivity of the melt complicate the growth of α‐alumina crystals. These difficulties were overcome by using a high‐pressure (300 psig) growth chamber, Na2O‐rich melts, and Ir for all surfaces in contact with the melt. These procedures were combined with the edge‐defined film‐fed growth technique to produce single‐crystal β alumina tubes and ribbons.
Subsolidus Equilibria in the TiO2‐SnO2 System
Authors: PARK M. , MITCHELL T. E. , HEUER A. H.
Published: October 2006

The subsolidus miscibility gap for the TiO2‐SnO2 system was redetermined. The critical temperature, 1430°C, is intermediate between that determined by Padurow, 1330°C, and that determined by Garcia and Speidel, 1475°C. Although the phase boundary is slightly asymmetric (the critical composition occurs at 47 mol% TiO2), it fits the regular‐solution model down to 1200°C. Calculations of the coherent spinodal using the regular‐solution model indicated depression of the spinodal below Tc, by 105°, 310°, and 387° for composition fluctuations along the [001], <101>, and <100> directions, respectively. These depressions of the spinodal are much greater than those calculated by Stubican and Schultz; this discrepancy is believed to result from an error in the latter workers’ calculations. During the present work, positive deviations from Vegard's law were found in this system. Both the magnitude and the sign of the deviation can be predicted using a theory based on nonlinear second‐order elasticity.
Kinetic Studies of the Thermal Synthesis of Calcium Silicates Above 1400°C: I, Dynamic Thermal Synthesis of Ca2SiO4
Authors: FIERENS P. , PICQUET P.
Published: October 2006

The dynamic reaction of SiO2 with CaO (1:2 mol ratio) was studied at temperatures up to 1500°C, especially those > 1400°C. Simultaneous TG and DTA, high‐temperature X‐ray diffraction (horizontal sample), and high‐temperature microscopy and dilatometry were used. The reactants (CaCO3 and quartz) were finely ground and mixed in stoichiometric amounts. Thermogravimetry was used to ascertain that the samples were representative and homogeneous. The reaction mechanism in the dynamic thermal synthesis of Ca2SiO4 was elucidated and confirmed by high‐temperature X‐ray diffraction.
Kinetic Studies of the Thermal Synthesis of Calcium Silicates Above 1400°C: II, Quantitative Kinetics of the Formation of Ca2SiO4 in the Presence of a Liquid Phase*
Authors: FIERENS P. , PICQUET P.
Published: October 2006

The final stage of the reaction mechanism elucidated in Part I of this paper is amenable to quantitative analysis. The reaction between an SiO2‐rich liquid phase and CaO is the rate‐determining step. Measurements were made by DTA and high‐temperature X‐ray diffraction. Activation parameters calculated from the kinetic data agree well with the proposed reaction mechanism.
A Model for Degradation of Ceramic Electrolytes in Na‐S Batteries
Authors: RICHMAN R. H. , TENNENHOUSE G. J.
Published: October 2006

Ceramic electrolytes derived from β‐alumina are cracked by electrolysis under certain conditions. Cracks form only when Na+ ions migrate through the ceramic and are converted to metallic Na, as in the charging of an Na‐S battery. The origins of mechanical damage are postulated and examined. A plausible mechanism consists of ceramic dissolution at preexisting surface cracks; it depends on the interaction of capillarity, stress, and selective removal of electrolyte from crack tips by effluxing Na. Relative solute fluxes are calculated for each contributing process. The proposed model is shown to account for many of the experimental observations, most notably a threshold current density below which no degradation is apparent.