摘要:

The Klcvalues for (100), (110), and (111) single‐crystal MgAl2O4as well as those for polycrystalline MgAl2O4with transgranular and intergranular fractures are presented and discussed on the basis of their elastic moduli. It is observed that the single‐crystal toughnesses are directly related to the elastic modulus. Polycrystalline and single‐crystal toughnesses are comparable; however, the intergranular fracture has the lowest toug

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09560.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The change in the measured high temperature thermoelectric power of wustite with time was determined. At all compositions, it was found this quantity decayed from its initial value to a lower steady‐state value. It is felt that this decay is due to ionic contributions to the thermoelectric power which become significant when sufficient time is allowed for the motion of ionic defects in the thermal gradien

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09561.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

This study compares the grain sizes of dense, equiaxed gadolinia (Gd2O3) specimens as determined by light microscope/polished surface and by scanning electron microscope/fracture surface techniques. The average intercept lengths (AIL) as determined by the two techniques were found to differ only slightly. For Gd2O3in the grain‐size range studied, a factor of ∼1.10 converts the fracture‐surface AIL to the polished‐surf

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09562.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Using the mass spectrometry‐effusion cell technique, Ge2N2O has been found to decompose under equilibrium conditions according toBetween 850 and 1000 K, the free energy change for this reaction is given byThe heat capacities of GezN2O and its silicon homolog between 296 and 738 K have been determined using differential scanning calorimetry. From these results it has been found th

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09563.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

A semielliptical flaw was produced by differential expansion of a brass bar cemented to a glashd surface. Crack growth was monitored by continuous observation in polarized light.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09564.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Contact damage was induced in zinc sulfide plates by pressing glass spheres into the surfaceshd The radial crack lengths (c) were measured and correlated with the applied load (P) using Pαd1f112, where diis the contact diameter. This yielded an excellent correlation and showed a load threshold and a transition region in the near field, as expected. Pαc3/2yielded a poorer correlatio

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09565.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Partial and total vapor pressures over Na2O.3SiO2anhd Rb2O.3SiOzmelts were determined at 1150° to 1300°C with the Knudsen‐effusion method. A Pt Knudsen cell was placed on a microbalance so that the weight loss due to effusion from the Knudsen hole could be recorded continuously. The specific vaporization rates are between ∼3.10−6and 3.10−4gcm−2s−1; the corresponding vapor pressures are between

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09566.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Self‐diffusion coefficients of the oxygen ion in single‐crystal forsterite were determined by the gas‐solid isotope exchange technique. The results in the 1472° to 1734°C range were described by D =2.85 (10−2exp (−416 kJ/mol/RT)cm2/s. In preparing the diffusion sample, argon‐ion milling gave a less defective surface condition than did chemi

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09567.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The development of microstructure in hot‐pressed SiaN4was studiehd for a typical Si3N4powder with and without BeSiN2as a densification aid. The effect of hot‐pressing temperature on density, α‐ to β‐Si3N4conversion and specific surface area showed that BeSiN2appears to increase the mobility of the system by enhancing densification, α‐ to β‐Si3N4transformation, and grain growth at temperatures between 1450° and 1800°. These processes appear to occur in the presence

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09568.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

When glass was treated in a hot alkaline solution containing a small amount of heavy alkaline earth elements such as Ba or Sr, sharp cracks formed on the glass surface. The severity of the crack formation was greater, the heavier the alkaline earth element. The cracks caused a drastic reduction in the mechanical strength of the glass.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb09569.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY