From powders to sintered pieces: forming, transformations and sintering of nanostructured ceramic oxides

The quest to produce fully dense nanostructured ceramics has received much attention over the past 10 years. This short review highlights some of the progress made and indicates some of the avenues where further research should prove fruitful. The review concentrates mainly on the attempts to produce nanograined dense ceramics from transition aluminas, where the phase transformation into the thermodynamically stable crystallographic alpha alumina just above 1000 degreesC plays an important role. The review also restricts itself to traditional low pressure room temperature forming methods and sintering cycles without any applied stress. Highlights for other systems such as yttria and zirconia where dense nanograined ceramics have been successfully produced will also be described and discussed. (C) 2002 Elsevier Science B.V. All rights reserved.