ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12614.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Whiteness and opacity were developed in lead borosilicate enamels by additions of 3 to 8 weight % of V2O5. These enamels were characterized by their fusibility, maturing at 1125° to 1200°F. Compositions were adjusted to provide fit and adherence to both glass and aluminum. Normal methods of preparing, applying, and firing were employed. Some of the experimental enamels for glass had marginal resistance to hot alkali solutions. Others appeared to be suitable for general‐purpose enamels, for which the chemical requirements are not so stringent. The enamels for aluminum, for which acid and weather resistance are desirable, were rated as having class A acid resistance, according to the classification system of the Porcelain Enamel Instit

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12615.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Zinc oxide was added to square‐loop ferrite compositions in order to obtain a lower coercive force and higher magnetic saturation induction than that usually possible from standard commercial square‐loop ferrites. Curie temperatures, hysteresis loops, initial permeabilities, magnetization curves, and switching times for these zinc‐bearing square‐loop ferrites were determined, and representative curves of these parameters are given. Grain structure and etchpit density were also studied, and typical photomicrographs are presented. Zinc oxide can be added to square‐loop ferrites to great advantage, but if too much is added, the useful magnetic properties degenerate c

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12616.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

Simple expressions of activities, as functions of composition, were developed from structural models for some borosilicate melts. Their applicability was tested with data from the liquidus curves of phase diagrams. If the heat of fusion is known, a value of the activity‐composition function can be calculated for each temperature of the liquidus curve. These values are compared with activities computed from the structural model. Calorimetric heats of fusion were available for the calcium borates studied. Experimental data from published phase diagrams for the systems Ca3(BO3)2–Ca2SiO4, Ca2B2O6–Ca2SiO4, Ca3(BO3)2–CaSiO3, Ca(BO2)–CaSiO3, Ca2B2O5–CaSiO3, CaSiO3–BaSiO3, and CaSiO3–K2SiO3were used. Simple ionic models seemed to be applicable in most cases, except for melts of highly polymerized mixed ions (metaborate‐metasilicate), for which the so‐called “group” model appeared to be useful. A value for the heat of fusion of CaSiO3was calculated from this work

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12617.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The effects of temperature and pressure on the wettability of metals by glass were studied. A system was completed that was capable of subjecting test combinations to temperatures up to 1400°C. at a working pressure of 10−5mm. of Hg. The variation in wetting with change in pressure and temperature was analyzed by the use of Young's equation primarily for the systems gold–, platinum–, and iron‐sodium silicate glass. The interfacial energy for the system gold‐sodium silicate glass was calculated to be 1230 dynes per cm. The limitations imposed on the use of Young's equation for analyzing wettability in systems in which an interfacial compound is formed are

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12618.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The cubic structure of yttrium oxide is stable to 1800°C. in air as indicated by petrographic, X‐ray, and differential thermal analyses. A change in lattice parameter of less than ±0.007 a.u. was observed on heating the oxide to 1800°C. The mean specific heat of Y2O3to 1600°C. was 0.13 cal. per gm. per °C. The coefficient of linear expansion to 1400°C. was 9.3 × 10−6in. per in. per °C. Compacts of Y2O3required a temperature of 1800°C. for vitrification. In equimolecular binary mixtures heated in the powdered state at 1500°C., Y2O3formed compounds with Al2O3and Fe2O3and solid solutions with ZrO2and HfO2. Y2O3did not react with CaO, MgO, or ThO2. Crystal types and unit‐cell sizes of the reaction produc

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12619.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

摘要:

The X‐ray measurement of lattice parameters of crystals at elevated temperatures provides a means of determining the true thermal expansion of a crystal. In this investigation, a furnace in which temperatures above 1200°C. could be accurately maintained and a specially designed circular back‐reflection X‐ray camera were employed in measuring the thermal dilatation of crystals representative of the cubic, hexagonal, rhombohedral, and tetragonal systems. Thermal‐expansion values up to 1200°C. are reported for magnesia, alumina, zinc oxide, rutile, beryllia, calcium oxide, and strontium oxide and for magnesia‐alumina, magnesia‐chrome, zinc‐alumina, and zinc

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12620.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12621.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1957.tb12622.x

出版商:Blackwell Publishing Ltd    

年代:1957

数据来源: WILEY