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Table 3 Peak temperatures of DSC endotherms for all samples and all four oven pressures used, arranged in order of increasing peak temperatures at 1000 mbar

From: The effects of instrument parameters and sample properties on thermal decomposition: interpreting thermal analysis data from Mars

Sample Decomposition type (source of gas released) DSC peak temperature (°C)
12 mbar 30 mbar 150 mbar 1000 mbar
Epsomite H2O (structural H2O) 94.2 107.9 103.1 127.8
Montmorillonite H2O (cation solvation water) 87.3 97.9 111.6 135.0
Goethite H2O (structural OH) 297.8 304.4 312.0 327.4
Kieserite H2O (structural H2O) 392.7 394.8 395.4 404.4
Kaolinite H2O (structural OH) 503.6 506.3 509.5 524.7
Alunite H2O (structural OH) 563.4 564.3 566.9 570.0
Magnesite CO2 loss (carbonate decomposition) 595.0 605.3 615.3 628.6
Alunite H2O (structural OH) 631.8 637.1 642.6 642.3
Montmorillonite H2O (structural OH) 699.3 702.2 712.1 763.9
Alunite SO2 loss (sulfate decomposition) 767.6 766.1 769.2 782.6
Calcite (<150 μm) CO2 loss (carbonate decomposition) 719.0 736.2 766.2 807.0
Calcite (3 mm crystals) CO2 loss (carbonate decomposition) 933.7 938.3 954.9 971.7
Epsomite SO2 loss (sulfate decomposition) 951.9 972.3 1033.4 1105.7
Kieserite SO2 loss(sulfate decomposition) 1062.6 1081.8 1100.4 1162.1
  1. Decomposition type shows what is being lost in the decomposition and measured by the EGA, with the source of the gas loss specified.