Phase diagram of the system: ZrO2–Cr2O3

The ZrO2-Cr2O3 system was studied by DTA 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 C and 50 mass% of ZrO2 are reported. Cubic zirconia solid solution decomposes at 1840 C, 25 mass% Cr2O3, by eutectoid reaction forming tetragonal zirconia solid solution with 9 mass% Cr2O3. This phase transforms at 1115 C to monoclinic zirconia solid solution. The enthalpies of these transformations are: 610 plus or minus 60 J/g for eutectic fusion, 110 plus or minus 10 J/g for eutectoid at 1840 C, 25 mass% Cr2O3, 22 plus or minus 5 J/g for eutectoid at 1115 C, 9 mass% Cr2O3 and 42 plus or minus 5 J/g for pure zirconia at 1165 C. 13 refs.