Vacuum Methods in Electron Microscopy. By Wilbur C. Bigelow

Microstructural evolution in two in situ reinforced composite systems, one produced by partial reduction and the other by grain growth, has been examined over a range of size scales using light microscopy, scanning electron microscopy (SEM) and transmission electron microscopy (TEM). Metal-ceramic matrix composites were formed by the partial reduction of Al₂O₃–Cr₂O₃ solid solutions to form Cr metal particles in an Al₂O₃–Cr₂O₃ matrix which had a lower Cr₂O₃ concentration. In a second system, grain growth of Si₃N₄ during liquid phase sintering produced large, whisker-like grains in a fine-grained Si₃N₄ matrix, bonded by an oxynitride phase. The mechanisms controlling microstructural evolution in these two systems were examined.