QUANTITATIVE PHASE-ANALYSIS AND THICKNESS MEASUREMENT OF SURFACE-OXIDE LAYERS IN METAL AND ALLOY POWDERS BY THE CHEMICAL-GRANULAR METHOD

The principles of the chemical-granular analysis of metal and alloy po wders are reviewed and the results are compared with those provided by the spectroscopic analytical techniques XPS, AES and SIMS, including ion etching in their depth-profiling mode, when they are applied to th e same materials. Several examples are analysed and it is shown that t he chemical-granular method alone can provide the very same informatio n as depth profiling. However, it is averaged over a macroscopic powde r sample in contrast to one or a few single particles. Nevertheless, i t is the combination of the chemical-granular and depth-profiling anal yses that really provides an unparalleled description in quantitative terms of the phase composition and microstructure of either multiphase and/or irregular surface layers resulting from oxidation, precipitati on or contamination. (C) 1998 Elsevier Science B.V. All rights reserve d.