TA Instruments TGA 2950 - Page 178

Appendix B
B–40 TA I NSTRUMENTS TGA 2950
with from 80 to only 5 for each Hi-Res
TM
mode
while covering the majority of materials of
interest.
The next step is how to proceed after the first
Hi-Res
TM
run is complete. If the first run was
made at resolution setting 3.0, try the second one
at 4.0. Generally, increasing resolution setting
by a whole number will increase the time to
complete the TGA scan by a factor of 2 to 5
times. Therefore, you must consider whether
you can afford the added run time as well as the
extra setup time. This balance between in-
creased run time and adequate resolution is
usually the determining factor on what resolu-
tion setting to live with.
The benefit to having more range and resolu-
tion to the resolution setting than seems to be
necessary, is that on a rare occasion a material
requires a very fine adjustment or an extreme
treatment. Dont forget that the maximum
heating rate is a factor in determining resolution
as well as the resolution setting.
Lower resolution settings allow materials which
already have well-separated transitions to be
analyzed at super high heating rates such as
200
°
C/minute with excellent resolution in a
fraction of the time required at a constant rate of
20
°
C/minute. Resolution settings above 5.0 are
useful when exact decomposition temperatures
are needed ,or when the decompositions are
explosive in nature, or when overlapped transi-
tions are extremely close but highly temperature
selective.