Dear All,
One layer was inorganic and the other was organic material with different thermal properties than if the sample kept as inorganic part in contact with crucible or vice-versa, will gives different measurements.
Mostly it will not affect. If the top layer is very much protective, there will be slight peak shifting to higher temperature.
Differential scanning calorimetry (DSC) is primarily well-suited for the analysis of powdered samples. Nevertheless, you may try to adapt the technique for your small flat sample constituted by two layers of different materials (organic and inorganic). Pursuing that goal, you can embed the sample within powdered (calcined) α-alumina ─ or other suitable inert substance ─ to improve thermal conduction between both layers of the sample, viz. the whole sample, and the crucible material. Keep the inert powder loosely packed if either phase change transformations or reactions between de sample and the atmosphere can possibly occur. Otherwise, improved thermal conduction may be possibly achieved by carefully packing tightly the inert powder around the sample. Consider to run a comparable blank essay with the inert powder but without the sample. It may prove convenient to judiciously select the crucibles material to ensure both good thermal conductivity and low thermal inertia ─ thus avoiding thick and/or heavy crucibles with a relatively high heat capacity. A certain minimum quantity of sample will be needed so that meaningful results can be possibly obtained, and consequently, several small fragments of the flat sample may have to be analysed together.
Dear Zheng,
In my point of view if, first or second order differentiation will apply it will gives result more accurately. Slow heating or cooling rate will produces external reactions in the time of calibration as well as DEC has some limitation from 10 K/min to 50 K/min heating or cooling rate. I required some of the research papers which give the answer of my question. Still ! waiting for the valuable guidance and suggestions.
it do have some effect, depending on the heat transfer properties. You may determine their heat capacity and conductivity first. Then test the film separately and see the heat flow changes on DSC curves. I suggest to use several heating rates to compare the effect of heating rate. What kind of parameters you would like to determine for this bi-layer materials? What is the thickness of the layer? It deserves to investigate when such properties can show the final performance of the device that uses this film material.
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