摘要:

Sinterable cubic aluminum oxy nitride (ALON) has been prepared by carbon reduction of aluminum oxide inflowing nitrogen. Three different sources of Al2O3(A12O3from clay, commercial A12O3, and A12O3derived from AlCl3.6H2O) and two different sources of carbon (carbon black and starch) were used. Pressed pellets of ALON powder were sintered in N2at 1950°C greater than 95% of theoretical density

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10232.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

It is shown that electron paramagnetic resonance spectroscopy provides an accurate method for measuring the preferential orientation of axial crystallites in ceramics. Since the physical properties of ceramic materials are correlated with the degree of this orientation, EPR can be a convenient and useful tool for the characterization of ceramics.

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10233.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The thermoelectric coefficient of cobaltous oxide was measured as a function of temperature and oxygen activity between 1000° and 1400°C. Results conform to ideal point defect theory at high temperature and high oxygen activity. Minority electrons are detected near the low‐oxygen activity phase boundary. At low temperature and high oxygen activity, deviations from ideality are detected in that oxygen exponents of the hole concentration exceed that predicted by Ideal point defect the

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10234.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Alumina and silica powders were sintered at 1250° to 1460°C in the presence of liquid phases containing CaO, A12O3, and SiO2. The data were analyzed using the equation D = K log t +C and the Arrhenius equation. The activation energy for sintering decreases with increasing amounts of liquid phas

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10235.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The thermal diffusivities of several molybdenum/alumina cermets were measured using a transient heat‐flow, semi‐infinite plate method. The cermets had thermal diffusivities significantly greater than those of 94% A12O3alumina. A 50150 wt% cermet had a thermal diffusivity of 0.102 cm2/s at 313 K, while the alumina had a value of 0.067 cm

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10236.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The electrical conductivities of single crystal and polycrystalline MgAl2O4and Y3Al5O12were measured to 1260 K using a three‐contact, guard‐ring technique. The electrical conduction mechanisms change with temperature, with anomalous oxygen pressure and time‐dependent inflections in log σ versus T−1curves between 900 to 1000 K. The conduction processes of Y3Al5O12and MgAl2O4appear to be similar and possibly related to A13+ion d

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10237.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The difference in the planar coupling coefficient, kp, of two PZT specimens with different grain sizes under the same poling treatment was attributed to a greater tendency for microcracking in the large grain‐size specimens. In the absence of microcracking, as shown in small grain‐size specimens, the decrease in kpand failure of the poled specimens is attributed to slow crack growth. The optimum poling conditions for small grain‐size specimens were evaluated in terms of reducing the slow crack‐growth

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10238.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The activation energies for densification, creep, and grain‐boundary sliding in HP‐Si3N4are consistent and large, approaching the heat of sublimation of Si3N4. If solution‐precipitation through the intergranular glass (or fluid) is invoked as a common underlying mechanism, then it can be concluded that the high activation energy results from the high heat of solution of the crystal into the glass. This is consistent with the finding that it is difficult to retain Si3N4in a glassy

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10239.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

Samples of plate glass containing a small amount of arsenic oxide as well as arsenic‐free samples were subjected to gamma radiation from a cobalt‐60 source after which modulus of rupture measurements were made. The arsenic‐containing glass showed a significant increase in strength upon irradiation while the arsenic‐free glass became

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10240.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

This study of C3S hydrates used a high‐voltage electron microscope equipped with a gas reaction cell that allows the specimen to be kept moist, and high‐resolution scanning and scanning transmission microscopes. Mechanical thinning and ion‐beam thinning coupled with fractography allowed this study of microstructural development with time, enabling both the morphologies and the spatial relations of the morphologies to be observed. The combination of several microscopic techniques allowed the hydration products of C3S to be classified and compared with those of Diamond for portland cement hyd

ISSN:0002-7820    

DOI:10.1111/j.1151-2916.1981.tb10219.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY