Sinter products can be
produced in many different ways. One of the most common
methods is mixing a fine powder with an organic binder. From
this mixture, a so-called green body with a specific
geometry can be shaped, for example, by means of
cold-isostatic pressing.
The first step of
subsequent production process is the burnout of polymeric
binder by thermal treatment.
The speed of this process
must be controlled very well. If the speed is too high, then
micro-cracks are produced in the green body, because the
created gases do not have enough time to diffuse out from
the inside. Otherwise, if the speed is too slow, then much
time is consumed, leading to an increase in production
effort.
The experience clearly
demonstrates that the best temperature profile for the
burnout of the binder shows a constant mass loss rate.
Therefore, the aim of investigation of this process is the
determination of a set of temperature profiles for various
levels of constant mass loss rate.
This problem can be solved
experimentally by various measurements, executed under the
condition of a constant mass loss rate. Much more
universally and also much cheaper is the combination of a
series of measurements, executed with constant but different
heating rates, with the kinetic analysis. This way will be
demonstrated in the following:
|
Measurement
|
|
|
|
|
|
Instrument
|
NETZSCH
TG 209 C Iris
|
|
Temperature
range/¡C
|
RT ...
800
|
|
Heating
rates/(K/min)
|
0.01 ..
10
|
|
Atmosphere
|
N2, 20
ml/min
|
|
Samples
mass/mg
|
40 ...
50
|