ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16213.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16214.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16215.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16216.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTThe isotherms and boundary curves in that portion of the ternary system Na2O‐SiO2–CaO.SiO2–SiO2of direct application to glass technology, namely, from 64 to 78% SiO2, 0 to 20% CaO, including the whole of the field of the compound Na2O.3CaO.6SiO2, and portions of the adjoining fields of Na2O.2SiO2, Na2O.2CaO.3SiO2, CaO.SiO2, tridymite, and quartz, have been determined with greater precision than in a previous study2by greatly increasing the number of mixtures studied, and thereby decreasing the interpolation necessary in the interpretation. An extended discussion is given of the devitrification of glass, in which it is shown that the liquidus temperature is the only datum point which is solely a function of glass composition, and is unaffected by the past history of the glass or by fortuitous circumstances at the time devitrification is taking place. At the liquidus the first trace of crystalline phase is in equilibrium with the glass; above the liquidus the glass will dissolve any such crystals which may have been formed at some previous time, but new crystals cannot form; while only below the liquidus is there a tendency for crystals to separate. The driving force causing this reaction is derived from the difference in free energy between the unstable glass and the stable aggregation of crystalline phases, and this force is opposed by a resistance of the nature of a viscosity. The dissociation in the liquid phase of the compounds which separate on devitrification diminishes the rate at which the devitrification equilibrium is reached, and increasing the complexity of the glass will have a similar effect. The excess in surface energy at the interface glass‐crystal may have an influence at the instant of formation of the first infinitesimal crystal, hut after the crystal has grown to a dimension appreciably greater than the sphere of molecular action the excess energy at this interface ceases to be of importance. The only surface tension measurements which have been made on glass refer to the interface glass‐air, and the excess energy at this interface has no necessary correlation with the devitrificatio

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16217.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTThe effect of magnesia on the devitrifimtion of a certain soda‐lime‐silica glass has been ascertained. The initial glass had a composition 1.15Na2O.0.84CaO.6SiO2, and tridymite separated as primary phase. On substitution of MgO for CaO, tridymite remained primary phase, and the melting point was lowered, but the curve shows double inflection. Addition of 2% of MgO lowered the melting point almost 200°, with the glass passing from the field of tridymite to that of Na2O.3CaO.6SiO2, but with more than 3%, MgO diopside became the primary phase, and the melting point rapidly incre

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16218.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTThe effect of Al2O3the devitrification temperature of a soda‐lime‐silica glass approximately of the composition Na2O.CaO.6SiO2has been studied in two series of experiments. In one of these CaO was partially replaced by Al2O3until the final glass had the composition of the mineral albite, Na2O.Al2O3.6SiO2; and in this series of experiments the melting point of the glass was first lowered, until the glass passed from the tridymite into the Na2O.3CaO.6SiO2field; then rose slightly to a maximum, fell until the glass entered the field of CaO.SiO2, and then rose rapidly until the field of albite was reached. Glasses near albite in composition are practically impossible to crystalliie in the dry way. In the second series of experiments, Al2O3was added to the same glass, and it was found that the fields of tridymite and Na2O.3CaO.6SiO2were quickly passed through, with a smaller lowering of melting point than in the preceding series, after which the melting point rapidly increased, with CaO.SiO2as primary phase. It is shown that no generalizations can be made as to the effect of alumina on the devitrification of soda‐lime glass. The problem is one of the freezing‐point relations in a four‐component system, and in the absence of definite knowledge of the liquidus temperatures and corresponding stability regions in that four‐component system general statements would probably be misleading. In addition, the devitrification of some five‐component soda‐lime glasses containing both Al2O3and M

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16219.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTThis report gives the results obtained in the second phase of an extensive investigation of fireclay refractories. It is limited to the twenty‐six representative clays included in that investigation. The geologic formation, chemical analyses, and pyrometric cone equivalents are given together with such properties of the clays fired at two widely different temperatures, as porosity, shrinkage, thermal expansion, moduli of elasticity and rupture, and plastic flow. Data are given to show the conversion of aluminous fire clays into mullite and cristobalite by firing at certain temperatures. At higher temperatures the cristobalite is converted to glas

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16220.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTConsiderable difficulty has been encountered in developing methods suitable for determining the properties of a casting slip that in turn define the casting quality of the slip. A survey of the literature is made, especially that dealing with the colloidal phenomena of clay suspensions, which might be of assistance in solving some of the problems encountered in the use of the casting process.The term, casting quality of slip, is detined and the factors which influence this property are considered in detail. Control methods proposed by various investigators are discussed critically. A new method of slip control is suggested. The sources and remedies of some troubles encountered in the casting process are discussed.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16221.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY

摘要:

ABSTRACTIt is axiomatic that the mode of packing of very large volumes of particles of uniform shape and size is independent of the size of the particles, provided they are large enough for the effect of electrostatic forces, air films, etc., to be negligible. An apparatus is described, in which equal true volumes of approximately spherical particles, ranging in diameter from 0.2 to 0.0035 inch, pack practically to the same apparent volume. This apparatus was used in studying the packing of mixtures of two and three sues of particles. By plotting the data so obtained in diagrams of a particularly convenient character, it is shown that the apparent volumes of mixtures containing unit real volume of solid fall between limiting values which can be calculated from simple assumptions, and that their deviation from these limits depends in a definite manner upon the diameter ratios of the component particles. The conditions governing the application of the results of the study to ceramic technology are pointed out.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1930.tb16222.x

出版商:Blackwell Publishing Ltd    

年代:1930

数据来源: WILEY