摘要:

The tensile strength of polymer‐coated fused silica optical fibers aged in a moist ammonia environment at 23°C was drastically reduced compared to that of fibers aged under ammonia‐free high‐humidity conditions. However, most of the strength lost on aging in ammonia was recoverable by ambient desorption of the ammonia, in analogy to the strength recovery which occurs when fibers aged in water are

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15302.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The polarized Raman spectra of rare‐earth fluoride glasses based on BaF2and ThF4, in combination with ZnF2, YF3, YbF3, LuF3, andlor AlF3, are reported and compared with those of other heavy‐metal fluoride glasses. The spectra of rare‐earth fluoride glasses, especially those containing large amounts of AlF3, have relatively broad and mostly depolarized features, suggesting that these glasses are more highly disordered than fluorozirconate and transition‐metal fluoride

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15303.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The kinetics of densification of alumina powder compacts at 1000° to 1200°C were studied by using a dilatometer to monitor volumetric changes during hot isostatic pressing. The densification rate is proportional to the square of the applied pressure, and densification does not occur below a threshold pressure. Results are interpreted in terms of an interface‐controlled reaction mechanism involving the movement of grain‐boundary disloca

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15304.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Recent observations with both magnesia‐ and yttria‐partially‐stabilized zirconia (Mg‐ and Y‐PSZ) indicate an apparent anomaly between strength and toughness relations in these materials. The present communication attempts to rationalize these observations and suggests that the stress to initiate the tetragonal‐to‐monoclinic transformation in zirconia‐toughened ceramics may control their m

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15305.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Four‐point flexure tests were performed at 1100° to 1350°C on two hot‐pressed silicon nitrides, one in which the grain‐boundary phase was amorphous and one in which it was largely crystalline. Fracture stress and relative K1cwere plotted vs temperature. Fracture regions were analyzed by scanning and transmission electron microscopy. Grain‐boundary phases affected high‐temperature fracture si

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15306.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Coalescence and crystallization in powdered high‐cordierite glass were investigated by DTA, SEM, and XRD methods, using also thermal expansion and viscosity data. The apparent activation energy for crystallization obtained from the DTA experiments was about half that for viscous flow estimated from the viscosity. Crystallization in such a system is believed to be controlled by a surface nucleation mechanis

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15307.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The diffusivity of lead in a PbO‐SiO2melt was determined as a function of oxygen pressure from kinetic data for the oxidation of liquid lead covered by a layer of lead silicate melt which is short‐circuited to facilitate electronic transport. The diffusivity‐oxygen pressure relation thus obtained agreed well with the corresponding prediction based on definitions of the fluxes ofPb2+and electron holes and an appropriate equilibrium rel

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15308.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

The silver/palladium ratio, alloy form, and heating rate cause significant changes in the oxidation and reduction behavior of palladium powder as determined by thermogruvimetric analysis. Surface area and airflow had little effect on oxidation and reduction. Possible models to explain the changes are considered.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15309.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Barium titanate ceramics with high degrees of c‐axis orientation were fabricated from fibrous particles. The maximum piezoelectric constant, d33, obtained was ≅270 pC/N, which is much higher than values reported previou

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15310.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

A metastable modification of Y2GeO5is formed from an amorphous material prepared by the simultaneous hydrolysis of yttrium and germanium alkoxides. It has an orthorhombic unit cell with a =0.6068 nm, b =1.0695 nm, and c = 1.1994 nm. The chemical structure is described by the formula Y4(Ge2O6)O4.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1985.tb15311.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY