ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11091.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The compaction behavior of four ceramic powders of widely different hardness but of essentially the same particle‐size fraction (nominally 44 to 62μ) was examined by measuring the travel of a laboratory hydraulic press. The results revealed that the softer powders yielded a greater fractional volume compaction at a given pressure. An account of compaction by two largely independent probabilistic processes, the filling of large holes and the filling of small pores, led to an expression for the fractional volume compaction, , in terms of applied pressurewhich, with the proper choice of coefficients, atand kt, was found to be adequate to describe the behavior of all the powde

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11092.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

A controlled‐potential coulometric determination of lead, cadmium, and zinc in glasses is reported. The method consists of reducing or oxidizing the various ions at appropriate potentials. The integrated current resulting from the electrolysis is used to calculate the amount of substance present. The lower limit of detection, without background corrections, is approximately 0.2 millifaradays for each ion. The method is accurate and more rapid than the usual classical methods of analysi

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11093.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Compositional changes in a glass alter both the number of ions that contribute to a diffusion process and their mobilities. The present work comprises an investigation of the diffusional properties of a glass in which composition was maintained but the mobilities of the contributing ions were altered by previous heat treatment of the glass and by the application of hydrostatic pressure. Changes in the self‐diffusion of alkali ions, as evidenced by changes in the ac and dc electrical characteristics of the glass, indicated that the activation energy of diffusion depends on the structural state. The entropy and frequency factors, which also play a role in alkali ion self‐diffusion, appear, however, to be insensitive to the structural st

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11094.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The determination of the sag point is described. This index of the softening temperature of a glass is simply determined. The equation relating this useful index to the approximate viscosity in this temperature region is presented.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11095.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The mechanism of bond formation between alloys of Ni and single‐crystal alumina (sapphire) was investigated. Ni‐Ti and Ni‐Cr powder mixtures were melted individually on the sapphire surface at 1500°C under a pressure of 10−4mm of Hg. Interfacial energy was measured by the sessile‐drop method. Two basic mechanisms were involved in the bond formation, viz., solute metal segregation at the interface and an interfacial reaction. The selective adsorption and segregation of the solute atoms at the interface was confirmed by X‐ray fluorescence analysis and by interfacial tension measurements. X‐ray diffraction studies on the interface produced definite evidence of the formation of α‐Ti2O3in the Ni‐Ti and sapphire system. Although green coloration of the sapphire crystal adjacent to the interface with Ni‐Cr suggested the diffusion of Cr in Al2,O3, no compound or oxide of C

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11096.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Single crystals of yttrium‐aluminum garnet have been grown from molten PbO‐xB2O3by program cooling, wherexis between 0 and 0.36 mole. The field of stability of yttrium‐aluminum garnet is found to widen with increasing B2O3content in the solvent. A portion of a pseudo phase diagram for the quaternary system PbO‐B2O3‐Y2O3‐Al2O3is presented. The effect of substituting certain transition metal oxides in the crystals i

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11097.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

The thermal stabilities of some alkali and alkaline‐earth fluosilicates and cuspidine when heated in atmospheres of dry and moist air were investigated. IN the decomposition of K2SiF6the compound K3SiF7was noted. The alkali and alkaline‐earth fluosilicates lose SiF4whereas cuspidine does not. In moist air atmospheres, α‐cristobalite is found among the residual products from the fluosilicates of sodium and potassium. K2TiF6hydrolyzes, first at low temperatures to an intermediate series of compounds and then at higher temperatures to fluorine‐free potassium titanates. Both K2ZrF6and Na5Zr2FI3hydrolyze to ZrO2and the alkali fluoride by way of an intermediate heptafluoride

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11098.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Two effects of atmosphere on the sintering of alumina powder compacts were investigated. Changing the oxidizing conditions during early‐stage sintering measurements showed that, within the range −70°F dew point oxygen to −70°F hydrogen equilibrated with alumina, there was no observable effect on sintering rate. The effect of trapped atmosphere on closure of pores was determined from apparent density limits obtained at high sintering temperatures and long sintering times. The complete elimination of porosity during sintering of alumina was possible if discontinuous grain growth was controlled and if the ambient atmosphere was hydrogen, oxygen, or vacuum. Porosity could not be completely eliminated when the ambient atmosphere was helium, argon, or nitrogen (or therefo

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11099.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY

摘要:

Phase relations in the system Fe‐Co‐O have been determined between 1000° and 1300°C in oxygen pressures of 0.01 to 20 atm. Only the portion of the system between CoFe2O4and Co3O4was considered in order to determine those conditions under which a complete series of solid solutions could be prepared. No field width on either side of oxygen stoichiometry was detected for solid solutions between CoFe2O4and

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1962.tb11100.x

出版商:Blackwell Publishing Ltd    

年代:1962

数据来源: WILEY