While preparing/synthesizing TiO2 nano particles using sol-gel and hydrothermal methods, heating is done at various rpm. why then high or low ramping per minute? Also can I remove my sample from the furnace before it cool down to room temperature? What effect might it have if for instance it is removed at 50oC?
Another one is, if it cools down at your odd time, what effect could it have if left overnight before washing?
Fine TiO2 powder is hygroscopic (pulls water from the air, becomes moist and clumpy), so taking out at 50°C is a good idea.
I am not sure if I quite catch the rpm question? However change is thermal treatment temperature is like to led to phase transition it's well know that the amophous phase exist a temperature s below 200, whilst the Anatase/Brookite is more dominant a temperature between 300 -500 depending on nature of synthesis method..The rutile phase is more dominant a temperature s above 600.
The ramping may play a role: for example, if you use calcination to remove an organic molecule, you may want to use a low ramping to reduce overheating associated with the thermal decomposition of your organic. Ramping may also plays a role on the temperature of phase transitions. All this will be more clearly observed by performing a TGA-DSC experiment on you sample using different rampings, in order to determine the optimal ramping conditions for your sample.
Thank you my senior colleagues, Vadim, Raymond and Juliette. I really appreciate your comments
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