Ceramic nancomposites obtained by sol-gel coating of submicron powders

• Published in: Acta materialia Vol. 49; no. 5; pp. 811 - 816
• Main Authors: Dauger, A, Boulle, A, Oudjedi, Z, Guinebretiere, R, Soulestin, B
• Format: Journal Article
• Language: English
• Published: 14.03.2001
• ISSN: 1359-6454

MgAl2 O sub 4 -ZrO sub 2 nanocomposites were fabricated by conventional sintering of composite powders obtained by sol-gel coating of a submicron spinel powder. In the composite powder the zirconia grains remain narrow sized and completely tetragonal even after being heat treated at temperatures where a free xerogel is completely monoclinic. The sintered material exhibits a dense, fine and highly homogeneous microstructure. The zirconia nanoparticles are located at both inter- and intragranular positions and exhibit heteroepitaxial relationships with the surrounding crystals. Tetragonal zirconia seems to be stabilised by an interface effect. Both the scale of the microstructure and the fraction of intragranular grains were controlled by adjusting the mean grain size of spinel grains before coating and sintering conditions.