Thermogravimetry calibration

The calibration of the temperature axis in thermogravimetry is discussed in Chapter 3. 

E 1582 (1993) Standard practice for calibration of temperature scale for thermogravimetry... 

Instrumental. All Differential Scanning Calorimetry (DSC) runs were conducted on a Perkin-Elmer DSC-7 attached through a TAC-7 Thermal Analysis Controller to a DEC computer station 325c. All runs were conducted at 10°C/min. in N2 unless otherwise stated. Thermogravimetry was run on a Perkin Elmer TGA-7 attached through the same system as the DSC. Isothermal aging of samples in sealed capillaries were conducted in the DSC cell of a DuPont 9(X) Thermal Analyzer after temperature calibration. 

Thermogravimetry needs a check of the accuracy of temperature, mass, and time measurements. Practically all thermobalances are capable of producing good data with only infrequent checks of the calibration via a standard mass. Since changes in volume of the sample take place, a buoyancy correction should be done routinely. The mass, m, of the displaced gas can easily be calculated from the ideal gas law (m = pMAV/RT). 

Time-calibration, as discussed in Sect. 4.1, poses little problems. Any good watch or stop watch, as well as the internal clocks of computers, are usually adequate for the relatively slow heating rates used in thermogravimetry. For standard of time, see Fig. 4.3. 

Data Recording Unit 4.3 Temperature Calibration 4.4 Sample 4.5 Atmosphere 4.6 Heating Rate 4.7 Classification of TG Curves 4.8 Calculation of Mass Change Rates 4.9 Derivative Thermogravimetry (DTG) 4.10 Intercomparison of TG and DTA 4.11 TG Reports 4.12 References 5... 

For a simple calibration of weight loss, the weight loss of a standard material can be checked imder reprodncible conditions of sample mass, packing, heating rate, sample holder confignration and atmosphere type, flow, and pressure. The TGA of calcium oxalate monohydrate (CaC204 H2O) is often used as a standard for the calibration of mass loss in thermogravimetry. This is due to three well-resolved steps in its thermal decomposition. 

ASTM El 582-93, Standard Practice for Calibration of Temperature Scale for Thermogravimetry. 

E2008, Standard Test Method for Volatility Rate by Thermogravimetry E2040, Standard Test Method for Mass Scale Calibration of Thermogravi-metric Analyzers... 

E2550, Standard Test Method for Thermal Stability by Thermogravimetry E2551, Standard Test Method for Humidity Calibration (or Conformation) of Humidity Generators for Use with Thermogravimetric Analyzers... 

X-Pert MPD system with Cu Ka radiation. X-ray photoelectron spectroscopy (XPS) measnrements were carried out in an ultra-high vacuum set-up equipped with a Gammadata-Scienta SES 2002 analyzer. A flood gun was used to compensate for the charging effects. The binding energies were calibrated with the C Is peak (284.5 eV). Thermogravimetry was performed with a Calm TG-2131 thermobalance in pure O2 with a heating rate of 2 K/min. 

E1131 -03 Standard Test Method for Compositional Analysis by Thermogravimetry E1582-04 Standard Practice for Calibration of Temperature Scale for Thermogravimetry E1641-04 Standard Test Method for Decomposition Kinetics by Thermogravimetry... 

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