bluuebunny/crossref_metadata_2025 huggingface dataset:
HIGH TEMPERATURE LOAD AND FUSION TESTS OF FIRE BRICK FROM THE PACIFIC NORTHWEST IN COMPARISON WITH OTHER WELL‐KNOWN FIRE BRICK1
Authors: Wilson Hewitt
Published: July 2010

Seventeen samples of fire‐clay brick from the Pacific Northwest have been tested with twenty‐seven other commercial brands of fire clay, silica, magnesia, chromite, zirconia, diaspore, silicon carbide and crystalline alumina, as well as china clay and crystalline sillimanite products made at the University of Washington. The tests show that the fire‐clay brick of the Pacific Northwest vary considerably in quality. According to the high temperature load test, the majority of the local brick are among the upper grades, some are to be classed with the best fire‐clay brick and one equal to the best diaspore brick. The brick tested is not the best which can be made from Pacific Northwest materials, for the kaolins in eastern Washington and northwestern Idaho give opportunity for the production of an all‐kaolin fire brick.

A method is suggested for testing super‐refractory materials under load at high temperatures similar to the standard load test for fire clay and silica brick except that the temperatures are measured by cones, and are raised until 10% linear deformation of the brick is obtained. The rate of heating and soaking varies with the brick under test, and the principles learned from the cone fusion test are used in the application of heat. A numerical value, expressing the area under the cone‐shrinkage curve, affords an easy method for comparing the high temperature load resistance of various refractories.

The brick which are best able to resist deformation at high temperatures are composed of crystalline materials which have developed a recrystallized bond of the same composition. These are crystalline silica, silicon carbide, corundum and sillimanite, and they resist deformation at temperatures close to their melting points. Amorphous materials like fire clay, diaspore, bauxite or even the very refractory crystalline materials lie chromite and periclase, which depend on amorphous silicates for a bond or are contaminated with silicate impurities. will fail with the softening of the bond of the amorphous impurities. The cone fusion of the brick as a whole can not be depended upon to indicate the resistance to load at high temperatures.
THE MANUFACTURE OF AN INSULATING BRICK FROM DIATOMACEOUS EARTH
Authors: Smith C. A.
Published: July 2010

Development of an Insulating Brick.—Pulverized diatomaceous earth was blended with each of the four clays, Tennessee ball, Bedford shale, Rock Hill, Tionesta, in percentages of 0, 5, 10, 15, 20, 30, 50 clay. Dry pressed briquettes were made using 50 to 60% water, and were burned at cones 06, 02 and 2. Heat conductivity tests were made upon the best bodies of the series.
THE DEAD BURNING OF DOLOMITE.—I1
Authors: Robson James Thomas , Withrow Jambs R.
Published: July 2010

This is the first of a series of articles covering the second phase of an investigation by the U. S. Bureau of Mines, in cooperation with the Ohio State University, into the possibility of utilizing dolomite as a base material in the manufacture of refractories.
SHEET STEEL COOKING WARE WHITE ENAMELS ECONOMICALLY SUITABLE FOR USE IN CHINA1
Authors: LAI CHI‐FANG
Published: July 2010

The research was carried on to develop data on sheet steel enamels which would be good enough and cheap enough for use in China. Substitutes for tin oxide were tested.

An efficient and cheaply constructed kerosene fired enameling furnace was designed and built. Little could be gained by work on the ground coats.

Sodium antimonate and calcined alumina yielded the cheapest enamels with quality almost equal to enamels made with tin oxide. Zirconium oxide yielded the best results when tested with acids. Cryolite could be reduced to the minimum and with benefit to the resulting product. High feldspar enamels proved to be most satisfactory. High zinc oxide content greatly increased the gloss but lowered the opacity. Calcined alumina failed when used alone.
VARIATIONS IN SOFTENING POINTS OF REFRACTORY MATERIALS DUE TO RATE OF HEATING1
Authors: COLE SANDFORD S.
Published: July 2010

Results are given of a series of softening point tests upon several types of refractory materials in which the rate of heating to obtain cone 28 down was varied from one hour to five hours. The results are presented in order to show that much of the data obtained by a fusion furnace is dependent upon the rate at which the furnace is heated and that large variations will occur unless care is taken to duplicate conditions of previous tests. Conclusions reached were: that two laboratories must duplicate the essential conditions in order to obtain agreement that the furnaces should be of the same type and heated in a similar manner, that the variations reported by different investigators can often be traced to the fact that conditions have not been duplicated.
KILN CONSTRUCTION1
Authors: LYON J. B.
Published: July 2010

Seventeen periodic kilns were studied for construction and design details, operation, and results. Eleven were round and six were rectangular. Alterations were made in grate area proportions, floor openings, flue design, and dimensions; the firing conditions and quality of ware obtained with each were recorded. The data obtained show effect on heat distribution and on time and fuel expenditures. Detail designs of flues are shown and the data are in tables and graphs. Detail specification and bill of materials are given for the 30‐foot round kiln which was found to give best results in ware and costs.
NEW TYPE OF TUNNEL TANK REPLACES DAY TANK1
Authors: WILLIAMS WARREN S.
Published: July 2010

Current retail distribution methods compel the glass manufacturer to be prepared for rapid changes in style, designs, and colors. Small, flexible, producing units capable of accurate control and permitting rapid color changes or composition of glass aid in maintaining a close ratio between production and current sales. Day tanks are elastic in operation, but are not as economical or reliable as continuous tanks. A day tank was replaced with a tunnel tank (two feet wide by twenty feet long) of equivalent melting capacity per shift. Details of construction, drawing, gas consumption, filling, and operation are given. Advantages gained: dependable production with uniform color, melting conditions stabilized and assurred, producing capacity increased threefold without increasing fuel or labor costs, repair production loss cut, repair labor and material costs reduced.
THE DESIGN OF HOLLOW TILE DIES1
Authors: Greaves‐Walker A. F.
Published: July 2010

The die problem is stated in terms of plant experience. Questions of piston vs. auger pressure, dimensional relations, speeds, uniformity of feed, die shape, position and dimension of bridges, posts, and cores are discussed in relation to varying clay characteristics.
THE RELATIVE IMPORTANCE OF ERRORS OF SAMPLING AND MEASUREMENT IN CERAMIC RESEARCH1
Authors: Westman A. E. R.
Published: July 2010

The common use of average values based on measurements of a small sample of specimens in ceramic research is pointed out. The principal errors to which such averages are subject are described and the need for a method for proportioning sampling errors and errors of measurement shown. An equation giving the relation between sampling errors and errors of measurement is derived by expression of factors involved in statistical terms and combination of well‐known statistical equations. This equation is used for constructing a chart by means of which questions involving sampling errors and errors of measurement can be readily solved. This chart also enables one to visualize the rôles played by sampling errors and errors of measurement in determining the accuracy of an average. The general applicability of the method is pointed out and its theoretical limitations are discussed.
GRAPHITE AS A REFRACTORY*
Authors: Stonic Richard H.
Published: July 2010

AbSTRACT

(1) Some properties or graphite are discussed and industrial applications as a refractory arc enumerated. (2) Previous work on graphite, particularly during the World War on graphite crucibles, is reviewed. That work was directed toward finding substitutes for imported graphites and clays. Since peace‐time conditions were restored the manufacturers have returned to foreign sources, of raw materials and sonic reasons for this tendency arc advanced. (3) Analyses of Vera1 foreign and domestic graphites are tabulated. (4) Reports arc given on experiments 011 the thermal conductivity of clay‐graphite bodies with the effect of varying percentages of graphite on the conductivity.
EFFECT OF VARIOUS GASEOUS ATMOSPHERES ON THE VITRIFICATION OF CERAMIC BODIES*
Authors: BADGER A. E.
Published: July 2010

Various types of ceramic bodies were fired in atmospheres of O2, N2, CO2, H2, And A marked increase in the rate of vitrification occurred when bodies containing feldspar were fired in an atmosphere of H2O. This effect was explained on the basis of a feldspar‐water eutectic.
A MUFFLE KILN OF HIGH EFFICIENCY*
Authors: Norton F. H. , Duplin J. V.
Published: July 2010

A new type of inufAc kiln particularly suited for instruction, research, or the studio is described. A high efficiency, high maximum temperature, and quick action are its distinguishing features.
ENAMELS OF STANDARD COLORS FOR VITREOUS CHINA SANITARY WARE AT CONE 6*
Authors: Kauitz Karl M.
Published: July 2010

The composition and preparation of the six colorcd enainels for producing the standard color samples in use in the sanitary ware industry are given. These enamels can also be used for the production of a standard vitreous china sanitary ware at cone 6.
A FUSION STUDY OF THE HIGH FELDSPAR AREA IN THE FELDSPAR‐KAOLIN‐QUARTZ SYSTEM*
Authors: Waldschmidt M. H.
Published: July 2010

Pyrometric cone equivalent valucs of various mixtures of the three components are presented with sonic observations on deforination eutectics found and on the location of the true eutectic.
STRESSES IN DOMES AND CROWNS OF CIRCULAR KILNS*
Authors: Goodier I.N.
Published: July 2010

Previous papcrs on the analysis of stress in various kinds of domes and crowns of circular kilns point to the dcsirability of a simple and general method applicable to any proposed shape, and capable of indicating what shape will ensure the satisfaction of certain special stress conditions. The method given here can be applied graphically or analytically to domes or kilns, either complete or with circular openings in the crown.

The principal point of intcrest for masonry structurcs is whether tensile stresses will occur or not, their occurrence being rcgarded as a criterion of instability. In domes the circuniferential stress (acting across vertical sections through the axis of symmetry) may or may not be tensile according to the shape of the profile. It is shown that domes whose profilesare parabolas or catenaries are free from tensile stress, whether open at the top or not, and that openings are favorable to stability in kiln crowns of any shape of profile. The particular shape which ensures complete freedom from circumferential stress, tensile or compressive, is investigated with results at variance with those of a recent paper.1

The principal conclusions arrived at are given in the summary.
MECHANICS OF ENAMEL ADHERENCE, VIII*
Authors: King R.M.
Published: July 2010

The desirability of firing enamels under accurately controlled conditions has, in general, been recognized. The author has made a study of enamel firing under varying pressures and atmospheres (oxidizing, reducing, and neutral) as well as with accurately controlled temperatures. A special apparatus, which is described, was developed for this purpose and soiiie results of these studies under reduced pressure are given and analyzed. This analysis reveals some basic causes of gas defects in enamels.
THE EFFECT OF MECHANICAL PRESSURE ON THE IMBIBITIONAL AND DRYING PROPERTIES OF SOME CERAMIC CLAYS, II*
Authors: Westman A. E. R.
Published: July 2010

The apparatus and technique used in a study of the permeable‐pressing characteristics of ceramic clays, described in a previous paper with the same title, were used in making a detailed study of the effect of molding pressure on the properties of permeable‐pressed disks of Florida and Delaware kaolins. The effect of initially high pressures on the properties of disks made at low pressures was investigated, and the rate of water removal was studied. The permeable‐pressing characteristics of mixtures of clays and nonplastics were investigated at high and low pressures and the firing properties of pcrmeable‐pressed clay disks made in the previous investigation were determined. Further work with larger disks is in progress.
X‐RAY INVESTIGATION OF THE OPACIFYING COMPOUNDS PRESENT IN SHEET‐IRON COVER ENAMELS*
Authors: Andrews Andrew I. , Breen J. P.
Published: July 2010

By the use of X‐ray methods, sheet‐iron cover‐cnamel frits and fired enamels were investigated. The results obtained show that tin oxide exists as tin dioxide in the enamel, antimony as antimony pentoxide, fluorspar as calcium fluoride, and cryolite as sodium fluoride. Zirconium oxide does not exist as the crystalline zirconium oxide even when present as a mill addition. Variations in the compositions of the ordinary sheet‐iron cover enamels do not affect the identity of the crystals.
A SUMMARY OF THE OBSERVATIONS AND FACTS CONCERNING THE PHENOMENON OF REBOILING*
Authors: Lord James Osborn
Published: July 2010

The recent observations and generally accepted facts concerning the phenomenon of reboiling of enamels on sheet metals are listed concisely. Six photomicrographs are presented to show the outstanding characteristics of the enamels obtained by some of the treatments described in the paper. With no attempt at a final explanation, a series of the most obvious deductions to be drawn from the observations of the first portion of the paper is made. In conclusion, some of the various theories that have been expressed to explain reboiling are mentioned and discussed.
THE ELECTRICAL BEHAVIOR OF GLASS AT ROOM TEMPERATURE*
Authors: Guyer E. M.
Published: July 2010

New instruments and equipment are described for the measurement of the electrical conductivity of glass at room temperatures. The accuracy of the method is discussed and certain precautions are specified for this type of measurement. A short review is given of the results of measurements with such equipment on a series of glasses. In particular, experiments are described on the effect of (1) chilling, (2) prolonged heat treatment which produces an actual separation of phases, (3) mechanical strains, and (4) superposed radio‐frequency currents on the conductivity of the glass at room temperature. In conclusion, i t is pointed out that the results of these measurements indicate that the electrical behavior of glass at room temperature is of importance.
VISCOSITY‐TIME‐TEMPERATURE RELATIONS IN GLASS AT ANNEALING TEMPERATURES*
Authors: Lillie Howard R.
Published: July 2010

Viscosity data published by the author in 1931 are discussed with reference to their limitations. New experiments on fiber elongation in a redesigned apparatus are described in which one of the glasses previously used is tested. The results show that the viscosity of a newly drawn fiber increases with time of heat treatment according to a definite law which may be explained on the basis of a change in the state of aggregation in the glass. A finite equilibrium viscosity is indicated a t each temperature, this limit being approachable from either side depending on previous heat treatment of the sample. This is taken to indicate an equilibrium average size of aggregate for any temperature, the groups starting to break up again if the temperature is increased after a long treatment. The expression of Sheppard and Houck is used for estimating effective molecular or aggregate weights in equilibrium at various temperatures, an example being 112,000 at about 500°C. The variation of viscosity with time is at least one reason why glasses fail to conform to Adams' and Williamson's annealing equation at low temperatures.
NOTE ON THE DISCOVERY OF A KAOLIN DEPOSIT IN NEW MEXICO
Authors: Richard L. M.
Published: July 2010

There has recently been discovered in New Mexico a deposit of the English type of kaolin which is of more than ordinary interest. These beds are located in Township 21 South, Range 3 East, Dona Ana County, and occur about fifty miles north of El Paso, Texas.

The deposits are of the residual type and have been formed through the chemical process of decomposition of feldspathic materials and leaching. They do not outcrop naturally but occur in the upper workings of a mine at one time worked for metalliferous minerals. The present estimated depth is from 150 to 200 feet from the surface.

The kaolin is massive and white in color. Tunnels of great length have been driven through it and it stands in remarkable fashion. For the most part the kaolin appears to have been formed similarly to the deposits in England. It is imminently plastic and fine in grain and due to its extreme whiteness is suitable for paper filler.

Tests which have been made show it to have admirable working qualities, comparable with the imported English variety.
WATER‐TIGHT TERRA COTTA MASONRY*
Authors: Anderegg F. O.
Published: July 2010

In spite of the lessened opportunity for moisture to pass the face of a terra cotta wall as compared with brick masonry, certain precautions should be observed to produce a water‐tight wall, especially where the exposure is severe. The bearing of each of the important properties of masonry cements in regard to their application to terra cotta is pointed out and recommendations are made for suitable cementing materials. Suggestions arc offered for the selection of sand and for securing uniformity and intimacy of mix. A joint width of 3/16 to 1/4 inch is recommended where the regularity of the units permits. The joints should he shoved and given a tool finish at the proper stage of stiffening. The joints subjected to extra severe exposure should be packed with prehydrated mortar and properly tool‐finished. Mortar may be aided to adhere to a glazed surface either by using prehydrated mortars or by first painting the surfaces with cement paint. For back‐up, a hollow tile with webs vertical is recommended.
CAUSE OF DEFECTS IN ENAMEL FIRED ON CAST IRON AT TEMPERATURES ABOVE 725°C., I*
Authors: Zapffe C. A.
Published: July 2010

A previous investigation on enameling cast iron is continued. Various wet‐process enamels were fired at temperatures above 725 °C. (1335°F.). Blistering and pinholing, even at high temperatures, were found to be caused principally by hydrogen contained in the iron and not by carbon oxides. If carbon oxides form, they do not occur in sufficient quantities to deface the enamels. Dehydrogenized cast iron may be fired as high as 790°C. (1455°F.) with a direct application of sheet‐steel white cover coat and at 840°C. (1545°F.) with sheet‐steel ground coat without incurring defacement. The moisture content of certain constituents in wet‐process enamels at higher temperatures causes an important gas effusion by reacting with the metal. The characteristics of the behavior of hydrogen in cast iron during enameling are compared with those of hydrogen in steel.
SCRATCH BLISTERS, II
Authors: Zapffe C. A. , Yarne J. L.
Published: July 2010

The enamel defect known as “scratch blisters” is consistently found to be caused by hydrogen that is introduced in large quantities at scratch marks. Several independent phenomena may contribute this hydrogen. An electrochemical reaction between iron and its oxide scale during pickling increases the hydrogen absorption at the scratch sufficiently to lead regularly to scratch blisters when steel with a certain type of oxide coating is used. Galvanic nickel coatings aggravate scratch blistering in a manner that is not well understood. Surface impurities and mechanical effects may produce scratch blisters but only circumstantially. The rolling direction of the sheet is found to be related to the occurrence of scratch blisters.
RELATION OF SURFACE OXIDATION TO CERTAIN DEFECTS IN ENAMEL COATINGS ON STEEL, III
Authors: Zapffe C. A. , Yarne J. L.
Published: July 2010

Oxide on the surface of enameling stock is found to play an important part in controlling the occurrence of hydrogen‐caused defects. Actually, steel with a preformed oxide coating of certain characteristics may be fired directly with a white cover coat without incurring fish scaling, copperheading, blistering, or reboiling. The oxidizing treatment probably removes some of the inherent hydrogen from the stock and then prevents subsequent absorption during firing from the reaction of iron with moisture which remains in the dried enamel coating. The advantages of preoxidation are discussed.

All other gases that may evolve from the enamels pass through the enamel without causing defacement. The primary boil simultaneously oxidizes and hydrogenizes the steel; and the pickup of hydrogen, which occurs during firing, is often the portion responsible for subsequent fish scaling and reboiling.
FURTHER CONSIDERATIONS OF HYDROGEN AS A CAUSE OF ENAMEL DEFECTS, V
Authors: Zapffe C. A. , Sims C. E.
Published: July 2010

The argument that reboiling is primarily a function of hydrogen is expanded with additional evidence obtained from metallurgical research during the past year. The behavior of hydrogen in rimming‐steel enameling stock is discussed, and an explanation is given for the varying behavior of the edge and center sections of rimming‐steel sheet in the development of certain hydrogen‐caused defects.
EFFECT OF VARIATIONS IN COLOR STAINS AND FRITS ON COLORS PRODUCED IN PORCELAIN ENAMELS*
Authors: Cook Ralph L. , Pelz Robert W.
Published: July 2010

Abstract

A representative series of colors, blue, brown, green, red, and yellow, was selected for this investigation. Variations of the constituents for these five stains were made and the resulting colors produced in the enamels were measured by means of spectrophotometric curves. The influence of additions of barium oxide, lead oxide, and zinc oxide to the frit was also studied. The addition of lead oxide to the frit tended to give greater solution of the blue stains. The barium oxide additions dissolved the lead antimonate yellow the most, while the lead oxide had the least effect on the yellow stains. Variations in calcination temperatures of the red stains produced decided changes in color. The additions of lead oxide darkened the color produced with the red stains.
THEORY OF THE BEHAVIOR OF GLASSWARE IN SERVICE*
Authors: Glathart J. L. , Preston F. W.
Published: July 2010

Abstract

The most important characteristic of a piece of glassware such as a bottle or a jar is its serviceability, that is, the amount of use which can be obtained from it. In the case of glassware which is subject to repeated re‐use, this serviceability may be thought of in terms of length of life, measured either by months or years, if the service is uniform, or measured by the number of trips successfully undergone if it is not.

The termination of the serviceability of such glassware is due to breakage, and breakage in turn is, in the vast majority of cases, due to impact. But a piece of glassware may survive many severe impacts, only to succumb to a comparatively minor one. Impact alone is not the whole story. Glassware must be prepared for breakage by undergoing a process of use and abuse during which the surface is scratched, abraded, and otherwise damaged and thus rendered vulnerable to the final stroke.

In the present paper the assumption is made that in nearly all cases breakage involves two separate and independent processes, the “vulnerating” process and the final impact. On this assumption a mathematical treatment is evolved which yields a mortality curve showing the relation between the rate of breakage and the service age of a given installation of glassware. This curve has been found to represent quite accurately the results of a service test on glass tumblers conducted in an actual restaurant.

Impact strength, as determined by laboratory tests, declines with service age in a way consistent with the above assumption. These strength data, furthermore, may be correlated with the results of the service test.

Additional data are being secured from other service tests now in progress.
Color Fading of Underglaze Decalcomania
Authors: DONAHEY JOHN W. , RUSSELL RALSTON
Published: July 2010

A study was made of some possible causes of color fading of underglaze decalcomania used in the commercial production of semivitreous dinnerware, While the quality of the decalcomania employed is of primary importance, ware losses due to color fading can be minimized by careful control of glost firing procedures, adjustment of glaze composition, and proper fritting practice. Cone 2 dinnerware glazes identical in chemical composition but different in constituency were found to have widely different characteristics toward underglaze colors. Best results were obtained when lead oxide was fritted and 10% or more whiting was left unfritted and added as a mill addition. Low‐melting frits did not produce so good results as did the more refractory frits. Strontia, as a lead replacement, was effective in reducing color fading. Barium oxide also showed characteristics favorable to underglaze colors, but tin oxide, zinc oxide, and magnesia, even in small amounts, were decidedly harmful to most colors. When alumina and silica were varied and other oxides were kept constant, increases in alumina were decidedly unfavorable to most colors, resulting in extreme fading at the higher alumina contents. The effect of raising the silica content was generally favorable. For best results, glazes should be compounded to prevent the formation of low‐temperature melts. Adjustment of glaze composition to increase viscosity and lower surface tension of the molten glaze is suggested as a method of minimizing glaze attack on color.
Oxidation Studies of Some Natural Graphites
Authors: HEINDL R. A. , MOHLER N. F.
Published: July 2010

The rates of oxidation at 900°C. were determined for twenty natural flake and amorphous graphites from eight foreign and three domestic deposits. Methods of determining moisture, volatile matter, ash, and graphitic carbon in such graphites are described. Numerical constants were established for the oxidation rates under specific conditions. In general, the oxidation rate of graphite was inversely related to particle size. The rate of oxidation of Madagascar graphite varied with the deposit from which the graphite originated.

Summary and Conclusions

Methods of determining moisture, volatile matter, ash, graphitic carbon, flake thickness, and the rate of oxidation of graphite are described.

The oxidation rates at 900°C. were determined for graphites from twenty deposits: ten in Madagascar, three in the United States, and seven in other parts of the world.

Under the experimental conditions of this investigation the following results were noted:

(1) The oxidation rate of graphite in general increased as the average particle size decreased.

(2) The rates of oxidation for fractions of the Alabama and Pennsylvania graphites and those for the corresponding particle size of the sample that represented the type of graphite imported in large quantities from Madagascar were not greatly different.

(3) The oxidation rate was apparently peculiar to individual deposits of graphite in Madagascar. Ten graphites tested from ten different deposits had four distinct rates of oxidation.

(4) Numerical constants were established for the oxidation rate of natural graphites.

The oxidation rate of graphite apparently depends on more than one physical or chemical characteristic or on some other characteristic not yet studied. It may partially depend on the surface area and on the impurities that are present and their distribution. These factors may or may not be directly related to the service life of graphite crucibles because of the oxidation of the graphite.
Apparatus for Automatically Recording Strains Between Enamel and Metal
Authors: WALTON JESSE D.
Published: July 2010

The construction and operation of a mechanism for converting the movement of an enameled split ring into a suitable electrical signal to be automatically recorded is described. Strain curves are presented for a single enamel when applied to several metals. These data were used to determine the relationship between the strains recorded and the properties of the metals to which the enamel was applied.
Phase Equilibria in the System CaO‐TiO2–SiO2
Authors: DeVRIES R. C. , ROY R. , OSBORN E. F.
Published: July 2010

Results of a study of phase equilibria in the system CaO–TiO2–SiO2 are presented. A prominent feature of the liquidus surface is a large two‐liquid region which appears on the equilibrium diagram as a broad band extending from the SiO2‐CaO side to the SiO2‐TiO2 side of the triangle. Evidence for the liquid immiscibility and the significance of the resulting large high‐temperature liquidus region in silicate technology are discussed. Representative paths of crystallization of liquids in the system under equilibrium conditions are outlined. It is shown that solid solution in the system is virtually nonexistent except for the small‐scale substitution of Ti4+ for Si4+ in wollastonite. Indices of refraction of glasses are given. Composition and temperature are listed for the twelve liquidus ternary invariant points.
Effect of Na2O/K2O Ratio on Chemical Durability of Alkali‐Lime‐Silica Glasses
Authors: SEN SUDHIR , TOOLEY F. V.
Published: July 2010

The chemical resistance of mixed‐alkali glasses to water was measured by determining the sodium, potassium, calcium, and silicon ions extracted instead of evaluating it from the alkalinity of the mixed‐alkali extracts. In glasses of the composition K2O and Na2O 18, CaO 10, and SiO2 72% the minimum extraction of alkali (maximum durability) occurred for a K2O/‐Na2O ratio of 2.6/1.0 (by weight). Based on an ionic‐composition analysis of the results, an empirical index is suggested for determining the relative degree of ion‐exchange and network‐breakdown modes of reactions that occur when such mixed‐alkali glasses are attacked by water.
Mechanism of Material Transport During Sintering
Authors: WALKER RAYMOND F.
Published: July 2010

Several mechanisms, such as volume or surface diffusion, viscous or plastic flow, and vapor transport, have been proposed in the literature to account for the transport of material during the sintering process. The manner in which such mechanisms can be responsible for experimental observations is reviewed, and attention is drawn to the limitations imposed by the present understanding of the principles involved. Examples are given of the theoretical models and mathematical expressions which have been derived for particular mechanisms and of attempts to apply these to empirical data. Suggestions for further investigations are given briefly.
Note on Ultrasonic Absorption of Glass at Elevated Temperatures
Authors: STEIERMAN B. L. , WU J. C. C. , McCORMICK J. M.
Published: July 2010

The ultrasonic transmission properties of soda‐lime glass at elevated temperatures were measured in the frequency range 0.25 to 1.0 me. Single‐crystal sapphire rods were used as transmission lines between the sample and barium titanate transducers. A small but uniform increase in absorption of energy was noted up to 800°F. From 800° to 1500°F. there was a great increase in absorption of energy. At 1500° the energy passing through 1 cm. of soda‐lime glass was 1/500 of the incident energy.
Constitution of Bone China: II, Reactions in Bone China Bodies
Authors: PIERRE P. D. S. ST.
Published: July 2010

The reactions which occur on firing bone china are described and discussed with reference to the phase data for the system lime‐alumina‐phosphorus pentoxide‐silica. X‐ray examination of variously fired china bodies indicates that up to approximately 1000°C. the mineralogical interactions are similar to those that occur in earthenware; above this temperature the nature of the reactions is characteristic of the bone china body alone. Intimate mixing, high firing temperature, and fluidity of phosphatic melts combine to promote rapid reactions in bone china bodies. Thus, phase data may be applied profitably to problems involving the properties and behavior of bone china bodies at high temperatures. The failure of differential thermal analysis to yield satisfactory information is noted.
Sodium Self‐Diffusion Coefficients in Alkali Silicate Glass Melts as Obtained by a Microgravity Experiment
Authors: Braedt Michael , Frischat Günther H.
Published: July 2010

Sodium self‐diffusion in Na2O·3SiO2 and 0.5Na2O·0.5Rb2O·3SiO2 melts was studied at 1200°C under microgravity conditions. These D*Na values may be considered us intrinsic data, whereas experiments conducted under earth's gravitational acceleration are distorted by buoyancy convection effects and yield apparent values only. The microgravip diffusion data fit the curve extrapolated from lower temperutures quite well; however, the log D*Na=f(1/T) curve has an inverse S‐shaped form at 300° to 1200°C.
Forming and Sintering Behavior of B‐ and C‐Doped α and β‐SiC
Authors: Williams Robert M. , Juterbock Barbara N. , Peters Charles R. , Whalen Thomas J. , Heuer A.H.
Published: July 2010

The effects of forming pressure and sintering temperature on shrinkuge, density, and phase composition of α‐ and β‐SiC were determined. Alpha SiC developed the 4H phase at the expense of the 6H phase at >2150°C. The beta form converted to the 6H phuse at >2000°C, with intermediate development of the 15R and 4H phases
Compositional Trends in Photoelastic Constants of Borate Glasses
Authors: MATUSITA KAZUMASA , YOKOTA RYOSUKE , KIMIJIMA TETSUO , KOMATSU TAKAYUKI , IHARA CHIKASHI
Published: July 2010

The stress‐optical coefficients of binary and ternary borate glasses were measured and the factor (p·q), where p and q are the Neumann strain‐optical coefficients, was determined. As a modifier oxide was added to B2O3 glass, the stress‐optical coefficient decreased monotonically. It was found that the stress‐optical coefficient is determined mainly by the elastic modulus, but the factor (p·q) becomes significant when the content and polarizability of the modifier cation are high. It was also found that the factor (p·q) decreases when the content and polarizability of the modifier cation increase. The (p·q) was divided into the lattice effect and the atomic effect, and their compositional dependences were discussed.
Defect Chemistry of Donor‐Doped BaTiO3
Authors: CHAN N.‐H. , SMYTH D. M.
Published: July 2010

Donor additions to BaTiO3 up to a few tenths atom percent are compensated by electrons and the resulting electrical conductivity is independent of temperature and Po2 at 700° to 1000°C. The conductivities are impurity‐insensitive at very low Poz and high temperature where reduction is the major source of defects. Variation in the site occupation ratio (A/B in ABO3 has a small effect on the conductivities for donor additions in the 100 ppm range. Nb is more effective as a donor than is Al as an acceptor, and Nb can compensate approximately 2½ times as much Al on an atomic basis.
Pore Structure Damage in Blended Cements Caused by Mercury Intrusion
Authors: FELDMAN R. F.
Published: July 2010

Hydrated blast furnace slag and fly‐ash cement blends have been shown to be very impermeable. Porosity measurements of these materials by methanol and helium pycnometry have been less than the values obtained by Hg intrusion to 410 MPa. Results of the three techniques for hydrated portland cement were the same. A technique was used in which mercury could be removed by distillation after Hg intrusion, and intrusion was then repeated. This was performed on several cements and cement blends. Pore‐size distribution for the hydrated cement changed marginally but both blended materials changed markedly, displaying a coarser pore distribution. It was concluded that the latter bodies are composed of relatively large, but discontinuous pores, into which Hg enters by breaking through the pore structure.
Crack Growth in Silica Glass Under Dynamic Loading
Authors: HIBINO YOSHINORI , SAKAGUCHI SHIGEKI , TAJIMA YOSHIMITSU
Published: July 2010

A dynamic loading test at a slow strain rate was made to examine the stable crack‐growth process in silica glass under several environmental conditions. The temperature and humidity influence on the crack‐growth process was investigated in detail. Test results show that the transition from region I to region II occurs at a constant stress intensity factor, K, independent of temperature and humidity. The transition K value was determined to be 0.61 MPa.m1/2. Furthermore, it is clear that the crack‐growth rate is dependent on K, even in region II.
Shrinkage of Glass Soot Samples using Hot‐Stage Scanning Electron Microscopy
Authors: BISWAS DIPAK R.
Published: July 2010

Glass soot samples were generated by both flame hydrolysis and oxidation of silicon and germanium tetrachlorides. The shrinkage of these samples during sintering was determined accurately by hot‐stage scanning electron microscopy. Shrinkage data were analyzed by an extension of Frenkel's theory of viscous sintering.
Conductivity Maximum in Sodium Aluminoborate Glass
Authors: MARTIN STEVE W. , ANGELL C. AUSTEN
Published: July 2010

By taking advantage of an exceptionally wide range of glass formation made possible by adding Al2O3 to the Na2O‐B2O3 binary system, the presence of a maximum in specific conductivity, not predicted by weak‐electrolyte models, was demonstrated at –55% Na2O. The decoupling of conducting modes from viscous modes in the supercooled liquid, assessed at Tg, reaches a maximum at 45% Na2)O. A second regime of increasing conductivity at >60% Na2O seems to be associated with incipient compound crystallization.
Alumina Substructure and Electrical Conductivity in Vitreous Silica
Authors: DOREMUS ROBERT H.
Published: July 2010

A network of alumina cells that remains after a vitreous silica sphere is heated in hydrogen supports the suggestion that alumina and associated sodium and lithium ions in vitreous silica are nonuniformly distributed. This distribution explains the anomalously large diffusion coefficient and electrical mobility of these alkali ions in vitreous silica.
Barrier Layers in Semiconducting Barium Titanate Glass‐Ceramics
Authors: HERCZOG ANDREW
Published: July 2010

Methods were developed for the reduction and subsequent oxidation of glass‐crystallized barium titanate for obtaining surface and grain‐boundary barrier‐layer dielectrics, together with the solid state chemistry compatible with glassmelting, crystallization, and the diffusion processes involved. The material obtained can be described as an interconnected dispersion of semiconducting BaTiO3 crystallites sealed in a mostly glassy silicate matrix. Oxidation of this semiconductor leads to surface layers with very high dielectric strength, up to 106 V/cm, and resistivity of the order of 1014ω·cm. The properties of compound barriers consisting of a space charge layer and a thin insulating film are also described and conditions leading to glass‐ceramic materials having a positive temperature coefficient of resistance (PTCR) by the use of an anionic dopant are discussed.
Mechanical Properties of Densely Sintered High‐Purity Titanium Diborides in Molten Aluminum Environments
Authors: BAUMGARTNER H. R.
Published: July 2010

Titanium diboride powder, produced in an arc‐plasma reactor, was pressureless‐sintered to near theoretical density to produce materials of different grain sizes. Mechanical properties in an aluminum environment at 960° to 1000°C were studied by strength vs stressing rate and KIc tests. All materials experienced liquid‐metal embrittlement in aluminum containing Fe, Si, and P impurities. During exposure, these metals penetrate TiB2 grain boundaries and the impurities preferentially segregate there. Fine‐ and coarse‐grained materials exhibited stress‐strengthening (negative N) and stress‐corrosion (positive N) slow crack growth behavior, respectively. Results were interpreted in terms of opposing slow crack growth mechanisms.
Fracture of Ceramic‐Polymer Composite Biomaterials
Authors: YALVAÇ S. , HAND J. H.
Published: July 2010

Fracture toughness, strength, and elastic modulus of poly‐(methyl methacrylate) (PMMA) ‐ and poly(butyl methacrylate) (PBMA)‐impregnated alumina ceramics were measured as a function of polymer volume fraction, mean polymer particle size, and interfacial bonding between the polymer and ceramic. Fracture toughness was found to increase with increasing polymer volume fraction and decreasing polymer particle size. Interfacial bonding played a very important role in determining the fracture mode, which was interparticle and intra‐particle when the interface was coupled and uncoupled, respectively. Poly(methyl methacrylate) increased the fracture toughness of the ceramic 1.5 to 2 times more effectively than poly (butyl methacrylate). The elastic modulus was found to be unaffected by impregnation. The previously reported Bowie model was modified and proved to be useful. Single‐ and double‐crack versions of this model predicted strengths somewhat higher than those measured. This discrepancy and the scatter in the data were explained by the crack‐path tortuousity and the possibility of different mechanisms operating in different samples. Fractographs of the selected bend specimens were taken to support this argument.
Hindrance of Grain Growth in Al2O3 by ZrO2 Inclusions.
Authors: LANGE F. F. , HIRLINGER MARGARET M.
Published: July 2010

Alumina and Al2O3/ZrO2 (1 to 10 vol%) composite powders were mixed and consolidated by a colloidal method, sintered to >98% theoretical density at 1550°C, and subsequently heat‐treated at temperatures up to 1700°C for grain‐size measurements. Within the temperature range studied, the ZrO2 inclusions exhibited sufficient self‐diffusion to move with the Al2O3 4‐grain junctions during grain growth. Growth of the ZrO2, inclusions occurred by coalescence. The inclusions exerted a dragging force at the 4‐grain junctions to limit grain growth. Abnormal grain growth occurred when the inclusion distribution was not sufficiently uniform to hinder the growth of all Al2O3 grains. This condition was observed for compositions containing ≤2.5 vol% ZrO2, where the inclusions did not fill all 4‐grain junctions. Exaggerated grains consumed both neighboring grains and ZrO2, inclusions. Grain‐growth control (no abnormal grain growth) was achieved when a majority (or all) 4‐grain junctions contained a ZrO2 inclusion, viz., for compositions containing ≥5 vol% ZrO2. For this condition, the grain size was inversely proportional to the volume fraction of the inclusions. Since the ZrO2 inclusions mimic voids in all ways except that they do not disappear, it is hypothesized that abnormal grain growth in single‐phase materials is a result of a nonuniform distribution of voids during the last stage of sintering.
Deformation Behavior of UO2 Above 2000°C.
Authors: SLAGLE O. D.
Published: July 2010

The creep of UO2 under uniaxial, compressive loads was measured in the temperature range from 2100°C to 2600°C at stresses from 2 to 21 MPa. For T > 2100°C, the results indicate an enhancement in creep rate over that predicted from an extrapolation of reported lower‐temperature data. The high‐temperature creep data can be described by an Arrhenius relationship with an activation energy of 1250 kJ/mol. The stress dependence of the creep rate can be expressed as a logarithmic relationship with a stress exponent that decreases from 6.5 at 2100°C to 3.5 at 2600°C.
Defect Structure of Mg‐Doped LaCrO3 Model and Thermogravimetric Measurements
Authors: FLANDERMEYER B.K. , NASRALLAH M. M. , AGARWAL A.K. , ANDERSON H.U.
Published: July 2010

Chemical stability and cation stoichiometry determine the applicability of LaCrO3 as a high‐temperature oxide electrode. A model for the behavior of acceptor‐doped LaCrO3, as a function of oxygen activity is proposed. The model is in agreement with experimental data on Mg‐doped LaCrO3. Stability regimes and compensation mechanisms at various oxygen activities and temperature are presented.
A Rapid Torsion Method for Measuring the Viscosity of Silica Glasses up to 2200°C
Authors: WEISS WERNER
Published: July 2010

A thin, heated glass rod fixed at one end is quickly rotated around its axis in a small vertically positioned tube furnace. A computer is used to determine the temperature‐viscosity correlation by solving an integral equation from the measurement of the torsion moment, the speed of rotation, the diameter of the rod, and the knowledge of the temperature profile inside the tube. The advantages of this new method are the small sample mass of about 0.5 g, the fast measurement procedure, the possibility of using high temperatures, and the fact that there is no contact of the sample with any solid materials. Also, lengthwise strips made of glass tubings can be used. Some examples of measuring the viscosities in the working range of 105 to 1010 dPa. s of commercial silica glasses up to 2200°C are shown. Maximum deviations of ±14 K are possible.
Characterization of Melt‐Quenched Quasibinary II‐IV‐V2 Chalcopyrite Semiconducting Alloys
Authors: Cody Joyce M. , Risbud Subhash H.
Published: July 2010

Experimental work on melt synthesis, solidification behavior, and characterization of alloys in mixed II‐IV‐V2 chalcopyrite semiconducting systems is reported. Melting relations diagrams and transformations in solidified alloys in the pseudo‐binary systems ZnGeAs2‐ZnSnAs2 and ZnGeAs2‐CdGeAs2 were studied by thermal analysis. Decomposition of a 10 wt% ZnGeAs2‐90 wt% CdGeAs2 glass, characterized by transmission electron microscopy, revealed the onset of phase instability at ≥400°C.
Static and Dynamic Compressive Behavior of Aluminum Nitride under Moderate Confinement
Authors: Chen Weinong , Ravichandran G.
Published: July 2010

An experimental technique for imposing lateral confinement on specimens subjected to dynamic or quasi‐static uniaxial compression has been developed. Lateral confinement is provided by a shrink‐fit metal sleeve installed on the lateral surface of a cylindrical ceramic specimen. Experiments using this technique were performed on sintered aluminum nitride (A1N). The results show that the failure mode changes from fragmentation by axial splitting under conditions of uniaxial stress to localized faulting under moderate lateral confinement. The compressive failure strength of the A1N increases with the increase of confinement pressure under both static and dynamic loading conditions. The effect of strain rate on the failure strength appears to be independent of the confinement pressure.
Reference Relations for the Evaluation of the Materials Properties of Orthorhombic YBa2Cu3Ox Superconductors
Authors: Munro R. G. , Chen H.
Published: July 2010

Several expressions, suitable as reference relations, pertaining to the composition and temperature dependencies of the properties of orthorhombic YBa2Cu3Ox superconductors have been derived from statistical assessments of collections of data from independent experimental studies. Relations are given for (1) the critical temperature vs oxygen content, (2) the lattice parameters at room temperature vs oxygen content, (3) the lattice parameters at fixed oxygen content vs temperature, (4) the anisotropic thermal expansion vs temperature, (5) the isotropic polycrystalline thermal expansion vs temperature, and (6) the mass density vs temperature.