Low scan rate DSC study of the monoclinic-tetragonal transition in zirconia

The effect of heating and cooling rates on the DSC (differential scanning calorimetry) heat flux peak of the monoclinic-tetragonal transition of zirconia was investigated in the 0.4–20 °C/min scan rate range. While the peak position, shape and area at high to moderate scan rates are consistent with existing literature data, a ‘step change’ (i.e., a peak-less baseline shift) was observed for the extremely slow heating rate of 0.4 °C/min. As expected, peak profiles in the heating and cooling transitions are markedly different, the peak shape being strongly asymmetrical for the t → m transition, but very closely symmetrical for the m → t transition. As the cooling rate is lowered, the t → m peak is increasingly splitted into multiple components, whose individual properties have been fitted using Gamma distribution functions.

► Monoclinic-tetragonal transition in zirconia studied by DSC.
► Heating and cooling rates as low as 0.4 ̊C/min.
► DSC profile studied as a function of the scan rate.
► DSC profile strongly altered at very low scan rate.
► Step-like DSC profile in the heating, multiple peak splitting in the cooling.