TA Instruments TMA 2940 CE, Operator'S Manual

Page: 132 / 178

Using Your Options
TA I
NSTRUMENTS
TMA 2940 CE 4–44
The expansion coefficient (
α
) for stainless
steel as a function of temperature is shown
in Table 4.1 on the next page.
a. Choose the appropriate coefficient of
expansion (
α
) value for stainless steel at
the desired temperature.
b. Multiply this
α
by the total plate thick-
ness and the temperature change to
obtain the thermal expansion correction
factor.
c. Subtract the correction factor from the
apparent distance between the plates
( h* ) determined in step 1 to obtain the
actual distance between the plates ( h ).
Where:
h =
h* –
[
α
(µm/m°C)
x
∆
T(°C)
x
10.2 mm
x
10
-6
(m/µm)
]
3. Calculate 1/ h
2
.
4. Calculate a table of:
∆1/
h
2
∆
t
Where:
h * = apparent distance between plates
h = actual distance between plates
t = time
T = temperature.
versus T