摘要:

Since the invention of the auger‐type extrusion machine, there has developed a large business devoted to the production of extrusion machines of various types and sizes for the ceramic industry. During this time, a vast body of empirical knowledge concerning the design of augers, dies, and machines to do particular jobs has grown. As of today, no method has been proposed by which values may be assigned to the design parameters of an auger so that there may be reasonable assurance that it will extrude a material, the plastic properties of which may be known. This paper proposes a model for the operation of an auger on a material and adapts the theory of the screw conveying of solids in organic thermoplastic extrusion machines to the study of this model. The concept of the characteristic function, which describes the action of a particular extruder on a plastic material, is discusse

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09133.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

Surface‐tension data are reported for liquid Al2O3, B2O3, GeO2, P2O5, and SiO2. Abnormal positive temperature coefficients for B2O3, GeO2, and SiO2are shown to be due mainly to changes in the liquid structure (dissociation) with temperatur

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09134.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

A portion of the system CaO‐SiO2has been reinvestigated by high‐temperature microscopy. Direct observations at the liquidus establish a primary‐phase region for tricalcium silicate, which is shown in a revised phase diagram to melt incongruently. The tricalcium silicate primary‐phase field extends from the eutectic with dicalcium silicate at 2050 °C., 69.5% CaO, to the incongruent boundary with lime at 2070°C., 71.5% CaO, with a possible error in composition of ± 0.25%. The estimated accuracy of these temperatures is ±3° relative to one another, and ± 10° relative to the melting points of alumina and dicalcium silicate, for which the values 2040°C. and 2130°C. taken from the literature h

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09135.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

Data have been obtained on the corresponding partial water pressures and temperatures at which hydrated montmorillonites will dehydrate reversibly. The data support but cannot establish (unequivocally) the idea that mixed‐layer phases are metastable with respect to gross mixtures and usually persist metastably in the stability field of either the dehydrated or the hydrated phase. The influence of the host lattice (montmorillonite. or saponite, and the interlayer cation, Mg2+, Ca2+, Na+, and Pb2+) is clearly shown in the pressure‐temperature curves presen

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09136.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

The phase equilibrium diagram of the ternary system NaF–LiF–UF4described in this paper is based on evidence from thermal analysis and from microscopic and X‐ray analyses of samples obtained from thermal gradient quenching experiments. Temperature‐composition relations were established through the temperature interval between the liquidus and a lower limit of about 300°C. All the stable compounds in the binary systems LiF–UF4and NaF‐UF4, (including the subsolidus compound NaF·2UF4) display primary phase fields in the ternary system. No ternary compounds of NaF–LiF–UF4occur. The following eutectics are to be found in the ternary system: 60 NaF, 21 LiF, 19 mole % UF4, 480°C.; 35 NaF, 37 LiF, 28 mole % UF4, 480°C.; 24.3 NaF, 43.5 LiF, 32.2 mole % UF4, 445°C.; and 24.5 NaF, 29 LiF, 46.5 mole % UF4, 602°C. The compounds 7NaF · 6UF4and 7LiF · 6UF4display limited solubility in each other. The exact limits of the miscibility gap in the 7NaF · 6UF4‐7LiF · 6UF4jo

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09137.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

Vapor pressures of arsenic trioxide over glass have been determined. From these results, together with analytical data of trivalent and pentavalent arsenic in the glass and the oxygen pressure, the free energies of solution of arsenic trioxide and arsenic pentoxide have been calculated. In a similar way the free energy of formation of Na4As2O7from the oxides has been determined for comparison.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09138.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

The influence of iron deposition and nickel flashing on the adherence of oxides to enameling‐grade sheet steel has been examined. Nickel flashing promotes oxide adherence, and a correlation between oxide adherence and adherence of a directly applied titania self‐opacified cover‐coat enamel has been established. Further work is necessary, however, to obtain a satisfactory enamel surface texture under these conditions before the direct application of a cover‐coat enamel can become a commercial possibility. Similarly, good adherence of a titania self‐opacified cover coat applied directly to steel has been promoted by nitric acid pickling with and without a nickel‐flashing treatment. Finally, the iron content of a hydrochloric acid pickling bath and the amount of hydrogen absorbed by the steel during pickling have been shown to influence the amount of nickel deposited on the steel duri

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09139.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

The process whereby the components of a thermite are pressed into a desired shape and ignited to form a cermet is described. In this process, the oxide of the cermet (Al2O3) is produced from the oxidation of powdered aluminum and the metallic phase is produced from the resulting reduction of its oxide. A third component (clay, Al2O3, or MgO) is added to act as a control agent. Methods of compacting and firing are described. A table of oxides reduced by aluminum using this process is presented. The formation of metallic silicides and borides as the metallic phase of a cermet from the appropriate silicates and borates, or metallic oxides with silica or boric acid, is discussed. As an example, ZrSi2is produced by the reduction of either ZrSiO4or ZrO2and SiO2, and TiB2by the reduction of TiO2and B2O3. The following advantages may be obtained by this method: (1) inexpensive compositions, (2) low ignition temperatures (1800°F.), (3) high reaction temperatures (5000°F.), (4) short firing time (1 hour), and (5) controlled atmosphere unnecessary. A technique was developed whereby cermet test specimens could be prepared from the thermite reaction between aluminum and zirconium silicate. The tensile strength of the finished cermet is given at room temperature and at 2200°F. The apparatus used for determining these tensile strengths is described. Modulus of rupture data also are given. Other oxide thermites were added to the basic zirconium silicate thermite mixture. The effect of these thermite additions on the strength of the basic thermite is describ

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09140.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

摘要:

By partially substituting Sr for Pb in ceramic lead titanate zirconate compositions near the morpho‐tropic boundary, dielectric constants greater than 1300 can be obtained along with planar couplings of about 0.50. Calcium also raises the dielectric constant, but the planar coupling level is considerably lower than that obtained with Sr. Other effects noted with Sr are a lowering of the Curie temperature, a shift in the morphotropic boundary toward the rhombohedral side, and a decrease in the distortion from cubic symmetry. In addition, Sr was found to be effective as a fluxing agen

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09141.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1959.tb09142.x

出版商:Blackwell Publishing Ltd    

年代:1959

数据来源: WILEY