The degassing of the sample is carried out before the BET measurement. I want to know how much degassing time and temperature to performe on my sample (my sample is the copper powder with a melting temperature of 1085 ° C).
Hello Anis Aliouat
Degassing is required for the BET analysis. But best of my knowledge there is no perfect chat or list from which one can easily get the degassing time and degassing temp. data. As your sample is highly thermal stable then you can set a series of temp. with different time and perform the adsorption-desorption isotherm to get the desired specific surface area data. Generally you can start with 120(oC) for 80 min to the upper limit (as mentioned in the machine which you are using). But to perform the surface area study you must to the TGA analysis.
Regards
Dear Anis,
It is generally understood for 100 gm(even little less also can be taken) of Cu/Cu2+ powder, suitable degassing temperature range around 500-520K and overnight time may be taken.
Ashish
The surface of copper powder exposed to air should be partially oxidized or, at least, with oxygen atoms adsorbed on it. You should clean its surface, so you should perform a degassing process (0.0001 - 0.001 torr) a room temperature (RT) for 3 o 4 h, then to introduce hydrogen gas at RT and to heat the sample at 420 K for 1 h in order to remove adsorbed oxygen on copper surface, and finally to degas at 393 K for 4 h (or better overnight).
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