摘要:

ABSTRACTGlass is to be regarded as a liquid which has a viscosity so great as to be practically rigid; and the glasses of commerce are all solutions undercooled far below their normal crystallizing temperatures. Nothing more is known regarding the constitution of these highly concentrated solutions than is known about the constitution of other concentrated solutions. The phase‐equilibrium diagram gives no information as to the compounds present in the liquid phase, for there is no known correlation between the properties of a homogeneous system and those of the heterogeneous system formed from it on crystallization. Evidence based on the rate of volatilization of alkali from alkali‐silicate glasses does not indicate compound formation. The discontinuous change of properties of a glass in the “annealing range” has been considered by some to be evidence that the glassy state is a fourth state of matter separated from the liquid state by this transition temperature; by others, as indicating that above this discontinuity the material is a liquid, below it, a brittle solid. These views are unsound, because they are based on measurements of physical properties made with changing temperature when those properties themselves not only change with temperature but also require at each temperature considerable time to reach their equilibrium value. When the measurements are made on glasses which have been held at constant temperature long enough for the equilibrium value of the property to be attained, no discontinuities are observed and there is no justification for calling glass a fourth state of matter or for separating a “brittle” from a “viscous” temperature range. Arguments, based on the variation of physical properties with composition in which it is considered that such variation is represented not by a continuous curve but by a series of straight lines determined by the composition of hypothetical compounds, are shown to be theoretically improbable and not in accord with the facts. Recent speculations on the constitution of glass based on X‐ray evidence and recent studies of glass by means of X‐rays indicate that the glassy state is distinguished by a random nonrepeating atomic network. This conclusion is in harmony with the view that glass is an undercooled liquid representing a solution in which definite compounds ca

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19332.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY

摘要:

ABSTRACTUsing a new type of concentric cylinder viscosimeter, the viscosity, 7, and electrical resistivity, κ of some commercial glasses and the glasses of the soda‐silicate system have been investigated in the region of 700 to 1400 °C corresponding from 3 to 102poises and from 0.3 to 103ohms. The results in the viscous region show proportionality between log η and log κ in the region investigated. In the two glasses investigated at lower temperatures, it can be seen that the same constants do not hold thronghout the whole region. These results are discussed considering the kinetic picture of liquids (see sum

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19333.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY

摘要:

ABSTRACTThe evolution of gases during the firing or refiring of ground coats on sheet iron or steel may be the cause of certain types of copperheading in the ground coat or in blistering of the cover enamel. The fluidity of the ground coat in the melted state on the ware has an important bearing on its ability to free itself of the gases.The calculated refractory value of an enamel is an index of its fusibility and fluidity during the firing operations. It is therefore an aid in the compounding of enamels which will minimize the defects arising from the evolution of gases during the firing of the enamels.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19334.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY

摘要:

ABSTRACTThe reported characteristics of the reboiling phenomenon have been checked and additional data which influence reboiling have been obtained.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19335.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY

摘要:

ABSTRACTStrong and uniform adherence in white ground‐coat enamels can be promoted through special preparation of the enameling stock either through a plating operation or by deep etching the surface. The results obtained depend upon uniformity of the preparation of the base metal and the composition of the ground‐coat enamels used.It is necessary to compound the white ground‐coat enamel with considerable amounts of the accessory opacifiers in order to build up satisfactory opacity. Additions of opacifiers to the mill are also necessary. Fluidity of the enamel is important and should be high to decrease reboiling and to produce a smooth finish coat on etched stock. Addition of antimony trioxide to the raw batch of the enamel promotes adherence but develops rebo

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19336.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19337.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY

摘要:

ABSTRACTThe location, physical and working properties, chemical composition, and microscopic character of this flint, which has not hitherto been described, are presented.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19338.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY

摘要:

ABSTRACTA typical composition of a cone 10 raw glaze that possesses pronounced devitrification characteristics of commercial possibilities is given. The percentage limits of the components of the glaze, the rates of cooling and heating up, as well as the temperature range in which crystals are producible were determined. The effects of adding various types and amounts of colorants on the color and the color intensities of the crystals and the glass matrix are discussed. Optical data indicate the crystals to be members of the pyroxene group.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1934.tb19339.x

出版商:Blackwell Publishing Ltd    

年代:1934

数据来源: WILEY