ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02669.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02670.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYTechniques in light microscopy of ceramics are described. The information provided by transmitted light examination of thin sections is discussed with particular emphasis on polarization microscopy. The production of polarization colours and the use of retardation plates are briefly explained with reference to their use in the study of preferred orientation in alumina ceramics. The discussion relating to incident light examination of polished sections is mainly concerned with methods of disclosing microstructural details by various methods including polarization microscopy, interference contrast and etching. The final part of the discussion deals with methods of studying sub‐surface detail in polished sections of transparent ceramics, including the use of incident dark‐field and oil immersion objecti

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02671.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThis paper demonstrates how careful microscopy of worn ceramic surfaces can be used to provide information on the mechanisms of material removal. This information is necessary as a critical complement to wear‐rate data obtainable from simple wear tests alone (e.g. lapping with diamond grits). Scanning electron microscopy has been extensively used to investigate the changing appearance of worn surfaces as plasticity and fracture processes compete as materials removal and redistribution mechanisms. Examples of the use of secondary electron imaging at different surface tilts, back‐scattered electron imaging and stereo imaging are shown. Further, transmission electron microscopy of samples specially prepared to contain the worn surface layer can reveal the presence of phase changes accompanying wear. Furthermore, observations have been made of instances whereby brittle fracture has unexpectedly occurred as a result of repeated plastic deformation of surfaces at low contact severities.Some conclusions are drawn regarding the influence of specimen microstructure, abrasive grit size and environment of the wear of glass‐bonded (debased) alumina and titania mate

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02672.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe relationship between microstructure and the mechanical and electrical properties is outlined for the main types of zirconia ceramic. Microstructural and microchemical characterization of these materials by TEM at 1000 kV and 100 kV accelerating potentials is demonstrated by reference to selected examples representing fully and partially stabilized zirconia and zirconia‐toughened alumina. Grain boundaries and grain boundary phases appear to be particularly important in determining the way in which zirconia ceramic microstructures evolve during sintering and/or agein

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02673.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe development of second phase zirconia precipitates in a beta‐alumina matrix has been achieved using chemical reactions which occur during the firing process. The degree of success of each of several fabrication routes has been evaluated by use of toughness measurements and electron microscopy techniques. Approximately half of the routes yielded ∼90% retention of tetragonal zirconia, resulting in an approximate doubling of the Mode 1 critical stress intensity factor (K

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02674.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYVarious techniques for the preparation of cross‐sectional and plan view TEM specimens of surfaces and interfaces are described. Particular emphasis is given to preparative methods which are both generally applicable and which minimize differential thinning of the materials present on either side of the interface of interest, thereby improving the reliability of the approac

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02675.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYA wide range of scaling processes can occur during the high temperature oxidation of FeCr alloys. Here we discuss the relative merits of using alternative transmission electron microscopical (TEM) techniques, as applied to edge‐on foils, for characterizing some of the different diffusional and microstructurally limited processes which occur, in particular at oxide and metal‐oxide boundaries. We give results for interfaces in wüstite, which is formed very rapidly on pure iron, as well as for the more protective FeCr spinels and sesquioxides, as grown on FeNiCr alloys in both air and 1%C0

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02676.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe high temperature oxidation of metals and alloys is slowed to a useful extent by the presence of certain elements or their oxides in the metal or on its surface. Particles of the reactive element oxide are found in part of the oxide scale and, by an unknown mechanism, retard the diffusion of metal through oxide grain boundaries. Changes in texture are also observed, which might affect geometry of individual grain boundaries. In this study the rotational geometry of grain boundaries in nickel oxide scales has been characterized both in the presence of particles of cerium dioxide and in their absence. Proximity of the relationship of neighbouring grains to a coincidence orientation could have an important influence on diffusion rate. Ways of testing this are compared and a new method for analysing orientation data from electron diffraction is presented, which allows statistically sound conclusions to be drawn. The frequency of occurrence of coincidence orientations in the presence of CeO2is little greater than random, so one possible mechanism for the ‘reactive element effect’ may be rejec

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02677.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

SUMMARYThe basic principles of X‐ray photoelectron spectroscopy (XPS) and Auger electron spectroscopy are described and their relative advantages as analysis methods for ceramic materials are reviewed. Their application in ceramics technology is illustrated by examples taken from the fields of catalysis and mineralogy. In particular, attention is drawn to recent developments of XPS which make it especially attractive for the study of ceramic materials. These include quantitative application of the X‐ray photoelectron diffraction effect to layered, single crystal minerals; the development of higher energy X‐ray sources for XPS, and the attendant study of the Sils–KLL Auger parameter as a probe of molecular and crystalline structure; and the analysis of small (≃250 μm) surface featu

ISSN:0022-2720    

DOI:10.1111/j.1365-2818.1985.tb02678.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY