ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12889.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

Rate experiments made on the transformation of silicic acid into cristobalite, in the temperature range 945° to 1085° C, have demonstrated the existence of a measurable nucleation period. From its variation with temperature, a value of 102.8 kcal. per mole has been calculated for the activation energy of the nucleation process. A second step of the transformation, involving the growth and perfecting of the new phase, has been shown to occur with an activation energy of 50.9 kcal. per mole. From the shape of the rate curves it has been calculated that a superstructure having fairly well‐defined sequence rhythms of alternating three‐ and two‐layer structural units might be the end product of heating silicic acid in the temperature range covered by the present experiments. It also has been demonstrated that the degree of disorder increases from the core to the surface of the transforming cristobalite c

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12890.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The temperature dependence of the microhardness of the quartz structures of both SiO2and the isomorphous compounds AlPO4, GeO2, and LiAlSiO4has been examined. Particular attention has been given to the effects of the high‐low inversion, which has been found to be anomalous relative to the behavior of other polymorphic transformations. The high quartz structure has been found to be much harder and more brittle than low quartz, despite their very close structural similarit

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12891.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The strength of unglazed feldspathic porcelain test bars in air decreased with humidity at the time of breaking. Moderate vacuum increased strength. N2, CO2, O2, and H2were not effective in changing porcelain strength with respect to that in ambient air. Use of a so‐called compression glaze eliminated the deleterious effect of water. Several organic liquids, as coatings on unglazed test bars, were evaluated. Tests with acid and basic solutions indicated that porcelain strength decreased with an increase in the mole % of water present in the liquid coatin

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12892.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

Phase equilibrium data, obtained by the quenching technique, are presented for mixtures in the iron oxide‐rich part of the system CaO‐iron oxide in air and at 1 atm. O2pressure. Present data are combined with data available in the literature to construct phase diagrams comprising the region from liquidus temperatures to temperatures slightly below the soli

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12893.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

Methods for the analysis of silicate glasses are described for ferrous iron, for tri‐ and pentavalent arsenic and antimony when present together, and for selenium as Se2‐, Se°, Se4+, and Se6+. Analytical results are presented for FeO in the range 0 to 0.25%; for total As and Sb as tri‐oxide, 0.1 to 1.25%; and for total Se, 0.05 to 0.25%. Apparatus for the determination of FeO is described, and a comparison is made of analytical data for FeO versus light transmittance at 1000 and at 1050 mμ for the sam

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12894.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The specific heats of glasses reported in the literature since 1951 were studied in relation to the Sharp‐Ginther equation. It was found necessary to change the factors previously furnished for K2O and B2O3. The other factors were found to be satisfactory when compared with the new measurements. It was discovered that glasses containing oxides of metals with atomic weights above 50 (e.g. iron, lead, and zinc) did not accurately fit the Sharp‐Ginther equation over the complete temperature range desired. Provisional factors were calculated, however, for iron and manganese oxides from 0° to 60

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12895.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

The ability of elements to form glasses, the leading part played by the elements of Group VI (O, S, Se, and Te), and the possible influence of the elements of Group VII (F, Cl, Br, and I) are discussed. New glasses suggested by previous work were melted and the refractive index (n) and coefficient of dispersion (v) of some of them were measured. Inspection of then, vplots of oxide, sulfide, selenide, and telluride glasses shows that the area corresponding to them extends toward high values of refractive index (nmax= 5.3) and low values of dispersion coefficient (vmin=4).

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12896.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

A simulated extract approach was used to ascertain the identities of the products of reaction between a soda‐lime‐silica glass and water. The reaction between the glass and water was studied at 90° C. with reaction time periods up to 4 hours. The products of this reaction were found to be sodium metasilicate, calcium meta‐silicate, and metasilici

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12897.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY

摘要:

Specimens of commercial plate glass were compacted at 900°F. and cooled slowly to room temperature. Power loss was determined as the specimens were reheated and quenched from various temperatures within the range 200° to 1200°F. Irreversible increases in tan δ were found to occur at quenching temperatures below the transformation range as well as within it. The increases below the transformation range are considered to result from changes in the Na+ion distribution, established during cooling, among the interstitial holes. As shown by density measurements, the increases within the transformation range are associated with configurational changes in the basic silica network. A glass property that depends on the mobility of a constituent ion is determined by at least two states: (1) a configurational state of the silica network and (2) a distribution state of the mobile ion. The extent of compaction is clearly indicated in a family of curves of tan δ vs. quenching temperature, with compacting time as a param

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1958.tb12898.x

出版商:Blackwell Publishing Ltd    

年代:1958

数据来源: WILEY