摘要:

AbstractBased on the behavior of phosphates in silicate melts, a possible picture of the constitution of bone‐china bodies is presented. The characteristic features are the formation of fluorapatite and hydroxyapatite as the chief constituents of the rigid framework and of a glass high in lime having a higher refractive index than the glassy matrix of normal porcelain bodies. The translucency, the whiteness, and certain characteristic defects of bone china may be explained on this basi

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1941.tb14855.x

出版商:Blackwell Publishing Ltd    

年代:1941

数据来源: WILEY

摘要:

AbstractA study was made of the effect produced by calcium oxide in the set, color, luster, texture, and acid resistance of white and colored enamels.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1941.tb14856.x

出版商:Blackwell Publishing Ltd    

年代:1941

数据来源: WILEY

摘要:

AbstractThe confusion in identifying hydrogen as the predominating cause of certain defects in enamel on cast iron has been due largely to the close association of carbon and hydrogen in cast iron and steel. The principal relation of carbide and graphite to enameling defects is the release of hydrogen from the carbon during enamel firing. The much‐discussed “chill layer” therefore is important chiefly because this layer often contains hydrogen that is bound to the carbon in the cementite. Experiments show that when hydrogen is absent, regardless of the depth or nature of the surface chill, no pinholing or blistering results during firing at 725°C.Sources of the hydrogen that causes the defacement are found chiefly in melting and in casting. The low oxygen pressure of molten cast iron favors hydrogen absorption. Moisture in the atmosphere, in the charge, or chemically combined in the rust on scrap provides the greatest quantities of the gas, and moisture and organic materials in the mold are also prolific sources of hydrogen for absorption by the iron. At ordinary temperatures, rusting is often harmful.Flushing the melt with a dry, hydrogen‐free gas, such as nitrogen, removes the dissolved hydrogen, and defects during subsequent enameling will not occur unless hydrogen is obtained later from other sources.Chipping phenomena probably are caused chiefly by hydrogen effusion, just as are analogous defects in sheet‐steel

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1941.tb14857.x

出版商:Blackwell Publishing Ltd    

年代:1941

数据来源: WILEY

摘要:

AbstractThe present picture of the atomic arrangement in glass has developed from four kinds of information, namely, the laws of crystal chemistry, the X‐ray diffraction study of glass, the various measured physical properties of glass, and the kinds of materials and the ranges of composition in which glassforming properties exist. X‐ray diffraction studies establish the predominant type of bonding in the glass, for example, the tetrahedral bonding in silicate glasses. Secondary structural features such as those which change with annealing or conditioning do not show up in the X‐ray pattern. Most of the proposed structures are those which are suggested and are partially substantiated by X‐ray studies, those which fit the laws of crystal chemistry, and those which seem best able to explain the physical properties of the glass.The preliminary theory of immiscibility in glass systems has been extended to include a consideration of the temperature dependence. A study of thermal expansion in terms of the number of glassforming bonds allows a simple correlation between thermal expansion coefficients in the silica‐boric oxide and the soda‐boric oxide systems. The same kind of considerations used in discussing immiscibility may be used to give a quantitative treatment of the change in the coordination number of the boron atom when boric oxide is presen

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1941.tb14858.x

出版商:Blackwell Publishing Ltd    

年代:1941

数据来源: WILEY

摘要:

AbstractX‐ray diffraction patterns of three compositions of soda‐lime‐silica glass were made, and radial distribution curves for the three glasses were obtained from Fourier analyses of the patterns. The results indicate that the silicon atoms are tetrahedrally bonded to 4 oxygens. Each oxygen is bonded to either 1 or 2 silicons. If each sodium is assumed to be surrounded by 6 oxygens, each calcium must be surrounded by about 7 oxygens. The structure is similar to that of soda‐silica glass except that some of the sodiums are replaced by calciums. A qualitative correlation of the structure with density and coefficient of expansion

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1941.tb14859.x

出版商:Blackwell Publishing Ltd    

年代:1941

数据来源: WILEY

摘要:

AbstractResults on the separation of inhomogeneities in bottle glass by density differences have been improved by changes in technique and apparatus. The accuracy of chemical analysis has been increased by taking larger samples for analysis, although they represent smaller fractions of the glass. The new centrifuge is equipped with windows and a stroboscopic light so that the movement of the suspended particles may be observed as the separation takes place. It is thus possible to obtain a curve which gives the distribution in density of the particles of the powdered glass. This curve and the analysis of the fractions of the powder of extreme densities have shown considerable value in the interpretation of the causes of cordy glass. The density distribution curves, composition differences, and case histories of several bottle glass cords are discussed.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1941.tb14860.x

出版商:Blackwell Publishing Ltd    

年代:1941

数据来源: WILEY