摘要:

Incorporation of up to 0.4 wt% Na2O was found in the mullites of fused‐cast mullite brick. Sodium oxide incorporation probably requires very high temperatures and persists only when the material is quenched rapidly to room temperature; it may be stabilized by simultaneous entry ofZr4+into the mullite structur

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19619.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

The action of basic catalysts such as KH on the ammonolysis products of CH3SiHCl2, (CH3SiHNH)n, results information of polysilazanes of intermediate molecular weight (600 to 1800). Pyrolysis of these polysilazanes gives ceramic materials, which appear to be mixtures of Si3N4, SiC, and C, in yields of 80 to 85%.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19620.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Addition of TiO2under the solubility limit enhances the initial sintering and grain size of mullite; amounts in excess of that limit inhibit sintering and drastically increase the total porosity and mean pore size.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19621.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Measurements of polarized Raman scattering and fundamental ir reflectivity in Pb /Mn /Ga fluoride glasses are reported. The spectra are similar overall to those of fluorozirconates, displaying two main bands in both Raman and ir, with the higher‐frequency Raman band being relatively narrow and highly polarize

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19622.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Thermal expansion of ZrC, which has the NaCI type structure, was determined from, 120 to 300 K by a powder X‐ray diffraction method. The lattice parameter was measured precisely using a specially designed D‐shaped symmetrical back‐reflection‐focusing camera with the specimen hanging from a cryoflask in the vacuum chamber outside the camera on the Rowland circle. The average coefficient of linear thermal expansion of ZrC in this temperature range is 6.22 x 10‐6/K. The Zr/C ratio

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19623.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Glass soot samples were generated by both flame hydrolysis and oxidation of silicon and germanium tetrachlorides. The shrinkage of these samples during sintering was determined accurately by hot‐stage scanning electron microscopy. Shrinkage data were analyzed by an extension of Frenkel's theory of viscous sinterin

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19624.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Unidirectionally crystallized CaO‐P2O5glass‐ceramics were produced by reheating glass rods between 450° and 580°C (glass transition temperature ∼500°C) under a temperature gradient of 30°C/cm. These glass‐ceramics exhibit high bending strength (∼650MN/m2) and toughness. Sample preparation is described and compared with conventional unidirectional solidification of melts. The characteristic mechanical properties are discussed in terms of the texture of the g

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19625.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Expressions are derived which permit the analysis of creep data, obtained in bending, for poly crystalline ceramics subject to tensile cracking. A numerical example based on literature data indicates that by considering the effect of cracks much better agreement is obtained between diffusion coefficients inferred from the creep data and those obtained by direct diffusion measurements.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19626.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

Thin films of amorphous Si3N4were prepared by the rf‐sputtering method, and the effects of titanium and chlorine additives on its crystallization were examined. When Ti‐doped amorphous Si3N4was heated, TiN precipitated at>1100°C; the TiN precipitates promoted the conversion of amorphous Si3N4to β‐Si3N4. Chlorine led to preferential conversion of amorphous Si3N4to

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19627.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY

摘要:

By taking advantage of an exceptionally wide range of glass formation made possible by adding Al2O3to the Na2O‐B2O3binary system, the presence of a maximum in specific conductivity, not predicted by weak‐electrolyte models, was demonstrated at –55% Na2O. The decoupling of conducting modes from viscous modes in the supercooled liquid, assessed at Tg, reaches a maximum at 45% Na2)O. A second regime of increasing conductivity at>60% Na2O seems to be associated with incipient compound crystalliz

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1984.tb19628.x

出版商:Blackwell Publishing Ltd    

年代:1984

数据来源: WILEY