Appendix B
B–42 TA I
NSTRUMENTS
TGA 2950
Hi-Res
TM
Transition
Temperatures
The TGA provides precise weight measurements
coupled with relative temperature information.
The resolution setting of a Hi-Res
TM
ramp
controls the reaction rate of sample transitions.
It is reaction rate, more than anything else,
which will determine the apparent transition
temperature of a decomposition reaction.
The shift in measured transition temperature
caused by changing resolution setting can easily
be an order of magnitude larger than the thermal
gradients you are trying to correct with calibra-
tion. This effect can be clearly observed in the
mixture of bicarbonates example (Figure B.13,
page B-61). In light of this fact, it is acceptable
in many cases to simply not use temperature
calibration when employing the Hi-Res
TM
TGA
techniques for decomposition analysis.
To Next Page
Loading...
