Influence of furnace atmosphere

Clearly, the mass of a sample in a closed system remains constant and caimot be a function of temperature or time. Thermogravimetric measurements are only possible if the sample is free to exchange material with its immediate surroundings. An important requirement is therefore that the gas atmosphere surrounding the sample can be changed to suit the experimental requirements. 

If high concentrations of hydrogen are being used then special care must be taken to remove the risk of explosions. Instruments where the furnace does not come into direct contact with the atmosphere can be useful for these measurements. 

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