Thermo Fisher - Cahn Thermax 500 Thermogravimetric Analyzer (TGA)

Client-Run Instrument
Trainer: Kiran Subedi

Thermogravimetric Analyzing (TGA) is commonly employed in research and testing to determine characteristics of materials such as degradation temperatures, absorbed moisture content, the level of inorganic and organic components in a compound, decomposition points of explosives and the presence of solvent residues. It is also often used to estimate the corrosion kinetics in high temperature oxidation.

The Cahn TherMax 500 TGA system specializes in demanding applications where high temperatures, pressures, and aggressive atmospheres are required.  Pressure can be used to enhance or speed up reactions. The weight changes of a sample is measured over a given temperature and pressure range under specific environmental conditions.

The furnace temperature follows a temperature profile sequence established by the user in a method in the Thermax software. The software periodically records weight and pressure measurements and stores them on the computer.

After the measurement cycle or “run” is completed, the data file can be processed in the Analysis mode of the software. Raw or processed data may be plotted on the monitor display or on a graphics plotter, printed in tabular form, or copied on a separate diskette for archiving

The three parts of the Thermax 500 are the:

  • Mainframe - the instrument hardware which includes: pressure balance, furnace vessel, stand and elevator.
  • Console - which: houses the instrument electronics, displays data and warnings and connects the Thermax with the computer.
  • Pressure/Flow Controller - which: controls pressure in the instrument, controls flow for three (3) gases and indicates pressure in the instrument.
  • The Cahn Thermax 500 instrument measurea weight changes on samples of up to 100 grams,  from room temperature to 1100°C, with a maximum sensitivity of one microgram.
  • The furnace follows a precise temperature profile of ramps and isotherms, established by the user, under constant computer control.
  • Gas flow and pressure is controlled by a pressure/flow controller.
  • Time, weight and temperature data are acquired at defined intervals and the data is stored on the computer's hard disk.
  • Cahn's Thermax software allows you to edit and perform analytical functions on your run data. A permanent record of the raw data or the processed data can be made by printing in tabular form or copying to a diskette.

Product Specifications:


Weighing 100 grams
Volume 30 cc
Weighing Range  
Maximum Weight ±10 g
Sensitivity 1µg
Temperature Drift 10 µg/°C
Accuracy at ambient temperature <0.02%
Repeatability <0.001%


Temperature Range  
at ambient pressure Up to 1100°C
at 1000 psi Up to 1000°C
Maxiumum Heating Rate 25°C/min
Temperature Repeatability ±3°C

Pressure Level

Maximum Pressure at 25°C 1500 psi
Maximum Pressure at 1000°C 1000psi
Internal Volume 0.3 liters
Thermocouple 1/8" Chromel-Alumel
Atmospheres Static or dynamic gases including H2O, alcohols, aldehydes, ketones, alkanes, dilute acids, H2, CO2.
Sensitivity 1µg
Temperature Drift 10µg/°C
Accuracy at Ambient Temperature <0.02%
Repeatability <0.001%

From The Cahn Thermax 500 Operator's Manual