When using the T4P heat flow, consider the following information when selecting the pan type for your experiments.
Pan Resistance Correction
The DSC Q1000 provides a more accurate measurement of true sample heat flow by accounting for heat flow within the DSC cell sensor as well as between the sensor and the sample pan. The resultant sample heat flow is designated as T4P heat flow.
The heat flow between the sensor and sample pan is primarily affected by the sample pan thermal resistance, which, in turn, is a function of the pan material (thermal conductivity) and temperature, assuming that both the pan and sensor are perfectly flat surfaces and in intimate contact. This assumption, however, is not true, even if careful experimental procedure is followed when preparing samples. Therefore, the thermal resistance of the thin layer of purge gas between the pan and sensor must also be considered.
TA Instruments has included in the Q Series Thermal Advantage software fixed values for both pan and purge gas thermal resistances. The supported pan choices include aluminum, alodined aluminum, hermetic aluminum, gold, and hermetic gold. Purge gas choices include air, nitrogen, oxygen, helium. When running experiments where T4P heat flow is being measured, select the pan type and purge gas that will be used. If you are using a pan type and/or purge gas that is not among the supported choices listed, you will receive this message.