Anomalous densification behavior of Al2O3–Cr2O3 system

Densification behavior of (Al1-xCrx)(2)O-3 (where, x = 0, 0.1, 0.3, 0.5) compacts in the temperature range 1000-1700 degrees C under reducing condition were studied. Up to 1300 degrees C, densification behavior followed the normal trend, i.e., bulk density increases with increase in Cr2O3 content. Anomaly in the densification behavior was observed from 1400 degrees C onwards. Al2O3 samples showed high densification; but the addition of 10 mol%Cr2O3 resulted in a sharp decrease in densification; while further Cr2O3 addition showed a steady rise in densification. XRD studies revealed the solid solution formation starts at 1400 degrees C. A broad endothermic peak at around 1400 degrees C in DTA thermogram corresponds to the formation of solid solution which actually absorbs extra heat energy resulting less dense Al2O3-Cr2O3 compacts. The average grain size of sintered Al2O3-Cr2O3 samples increases with increase in Cr2O3 content. (C) 2015 Elsevier Inc. All rights reserved.