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Simultaneous thermal analysis (STA)

The simultaneous application of TG and DTA/DSC to a single sample in an STA instrument yields more information than separate applications in two different instruments:


Model:

STA 409 PG Luxx

Manufacturer:

NETZSCH Gerätebau GmbH

Year of manufacture:

2003

Temperature range:

25 to 1550 °C

Max. heating rate:

30 °K/min  (typical: 10K/min)

Atmosphere:

inert, oxidising, reducing, steam



Simultane Thermische Analyse 2

Simultane Thermische Analyse 3

The STA apparatus owned by the Chair of Ferrous Metallurgy comprises a high temperature furnace (1550 °C) and a water vapour furnace (1250 °C). This system is capable of performing simultaneous thermal analysis (STA, a combination of TG and DTA/DSC) measurements in the temperature range from RT to 1550 °C. The atmosphere can be modified from inert, reducing, or oxidising conditions. Working under vacuum is possible as well.

The simultaneous application of TG and DSC to a single sample in an STA instrument yields more information than separate applications in two different instruments:

  • The test conditions are perfectly identical for the TG and DSC signals (same atmosphere, flow rate, vapour pressure on the sample, heating rate, thermal contact to the sample crucible and sensor, radiation effect, etc.).
  • The analysability of the signals is improved, since two or more sets of information concerning the sample behaviour are always simultaneously available.

The determination of the high temperature phase transformation (Tγ→δ, TSolid, TPerit., TLiquid) in new steel grades constitutes a special research field. DSC measurements are an excellent method which record all transitions associated with an exo- or endothermic effect (= enthalpy change). With a very high accuracy almost all important phase transformations in steels can be measured and used to validate or to asses full phase diagrams. Therefore a platinum DSC sensor with a type S thermocouples will be used. The Pt/Pt10%Rh thermocouples of the DSC sensor are calibrated at the melting points of 7 high purity elements (In, Sn, Al, Ag, Au, Ni, Co) to achieve highest accuracies.