Reliability of scanning electron microscopy information

The reliability of information obtained with the scanning electron microscope is influenced by human and instrumental factors. The human factor enters, for example, when a microstructure is described as being typical of the material when in fact it is only a minor component. Some instrumental factors include charging of the specimen, problems differentiating between positive and negative relief and distortion of the shape of the sample in micrographs. The determination of the amount of a phase present in a composite is a complex problem involving both preparation of representative surfaces and appropriate methods of evaluation. A number of experimental results are provided. Where smearing of surfaces is not a problem, point counting evaluation on sawn surfaces is shown to provide reliable results.