ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02483.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02484.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA series of microstructural investigations has been undertaken in order to explore the reliability of particular etches in revealing microstructural detail in silicon carbide compacts. A series of specimens has been etched and examined following complete prior microstructural characterization by transmission electron microscopy (TEM), scanning electron microscopy (SEM) and X‐ray diffractometry techniques. In particular, the sensitivity of both a molten salt (KOH/KNO3) etch and a commonly‐used oxidizing electrolytic ‘colour’ etch to crystal purity, crystallographic orientation and polytypic structure has been established. The molten salt etch was found to be sensitive to grain boundaries and stacking disorder while the electrolytic etch was found to be primarily sensitive to local purity and crystallographic orientation. Neither etch appeared intrinsically polytype sensitive. Specifically, for the ‘colour’ etch, the p‐ or n‐type character of impure regions appears critical in controlling etching behaviour; p‐type impurities inhibiting, and n‐type impurities enhancing, oxidation. The need to interpret etching behaviour in a manner consistent with the results obtained by a variety of other microstructural techniques

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02485.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYA study of the factors that affect thinning rates and damage processes during the ion‐beam thinning of ceramics has been undertaken. The results of these studies are reported and related to the conditions necessary for the preparation of uniform damage free specimens. Particular emphasis is placed on the variations in specimen stoichiometry that can occur during ion‐beam thinning. It is shown that under certain conditions the positively charged ion‐beam can induce charged interstitial migration into the bulk of the sample. The extent to which this effect, atomic bonding, crystal orientation and beam conditions can produce non‐uniform samples is di

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02486.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe microstructure dependence of the creep and creep‐fracture properties of ceramics is illustrated with particular reference to the behaviour of magnesia, lime and silicon nitride materials. From a consideration of the various models proposed to account for deformation and fracture under high temperature creep conditions, a consistent interpretation can be provided for the diverse behaviour recorded for different ceramics as a result of variations in crystal structure, composition and phase distributio

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02487.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

The crystallization characteristics of two commercial calcium aluminate glasses have been studied using scanning electron microscopy. In particular it is demonstrated how atomic number contrast can be used to identify rapidly crystalline phases without the need for etching and the related loss of compositional and morphological information. From these studies and concurrent X‐ray analysis it is shown that the presence of barium oxide and silica has a marked effect on the crystallization behaviour of calcium aluminate glasse

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02488.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe nucleation and growth of lead dioxide on titanium substrate has been observed using scanning electron microscopy. The size and morphology of the PbO2nodules have been measured in an attempt to elucidate the nucleation and growth mechanism. The effects of temperature, current density and fluorine ion addition have been qualitatively determined.The structure of a film of PbO2formed on the titanium has been examined using TEM and found to be heavily strained and to contain lattice defects such as dislocations and stacking faults.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02489.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYIn the manufacture of synthetic fibres such as nylon and Terylene, ceramic surfaces are used to guide and control the threadlines. Successful operation is critically dependent on correct friction between the threadline and the surface it contacts; this is achieved by control of surface topography. Microscopy, particularly the SEM, has played an important role in understanding the characteristics of different surfaces, control of manufacture of the surfaces, development of new surfaces and processes, and the elucidation of plant problems. Examples of these applications are illustrated and discussed.

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02490.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYThe microstructure and the nature of some crystal phases in non‐ohmic ZnO ceramics containing 0·5 Bi2O3, 0·5 CoO, 0·5 MnO and 0·5 TiO2mol% were investigated by using various analytical techniques. The ceramics consist primarily of ZnO grains, and in addition, two titanium containing phases were found, a needle‐like Zn2TiO4spinel phase doped with bismuth and cobalt, and a cubic‐Zn2Ti3O8phase with some cobalt and manganese. The Bi2O3phase among the grains was found to be TiO2stabilized

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02491.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY

摘要:

SUMMARYSecretory proteins (casein micelles) were air dried prior to elemental analysis either without treatment, following glutaraldehyde fixation and dialysis, or following dialysis against distilled water. Samples were then examined by energy dispersive X‐ray microanalysis in a scanning transmission electron microscope (STEM). Untreated samples and samples dialysed against distilled water retain colloidal (bound) elements as compared to glutaraldehyde treated samples. Contamination of air dried casein micelles by ionic constituents in the non‐protein aqueous phase was observed in the untreated sample and in the glutaraldehyde treated sample. Dialysis of casein micelles against distilled water reduced contamination from the aqueous phase without diminishing the apparent concentrations of colloidal eleme

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1981.tb02492.x

出版商:Blackwell Publishing Ltd    

年代:1981

数据来源: WILEY