Phase diagram of the system: ZrO2-Cr2O3

The ZrO2-Cr2O3 system was studied by differential thermal analysis in the composition range from 0 to 40 mass% Cr2O3. The formation of extensive solid solutions (25 mass% Cr2O3 in cubic zirconia and 40 mass% ZrO2 in Cr2O3 at the eutectic temperature) and the eutectic point coordinate: 1950 degreesC and 50 mass% of ZrO2 are reported. Cubic zirconia solid solution decomposes at 1840 degreesC. 25 mass% Cr2O3, by eutectoid reaction forming tetragonal zirconia solid solution with 9 mass% Cr2O3. This phase transforms at 1115 degreesC to monoclinic zirconia solid solution. The enthalpies of these transformations are: 610 +/- 60 J/g for eutectic fusion. 110 +/- 10 J/g for eutectoid at 1840 degreesC. 25 mass% Cr2O3. 22 +/-5 J/g for eutectoid at 1115 degreesC, 9 mass% Cr2O3 and 42 +/-5 J/g for pure zirconia at 1165 degreesC. (C) 2001 Elsevier Science Ltd and Techna S.r.l. All rights reserved.