Differential scanning calorimetry DSC curve peak-splitting fitting method

Abstract

The invention discloses a differential scanning calorimetry DSC curve peak-splitting fitting method. According to the method, a heat flow rate-temperature curve is drawn by utilizing DSC test data; determining a baseline required for calculating the peak area; determining the position of a possible endothermic (exothermic) peak tip; according to the base line and the peak tip position, a Bigaussian function is adopted to perform peak division on the coincident peaks; dividing substance types to which different peaks belong according to peak temperature positions of measured substances, superposing the different peaks of the same type of substances to obtain peak areas of the substances, calculating enthalpy change values according to the peak areas, and obtaining concentrations of the substances according to the enthalpy change values. According to the method, the overlapping peaks of the DSC curve can be well distinguished so that the concentration of each substance is accurately calculated, and the calculation precision of the concentration of an erosion product is greatly improved.

Description

technical field [0001] The invention relates to the technical field of thermal analysis, in particular to a method for fitting peaks of differential scanning calorimetry (DSC) curves. Background technique [0002] Differential Scanning Calorimetry (DSC) is a thermal analysis method that measures the relationship between the power difference input to the sample and the reference object and the temperature at a programmed temperature. Differential Scanning Calorimeter The recorded curve is called the DSC curve. It takes the rate of heat absorption or heat release of the sample as the ordinate, and the temperature T or time t as the abscissa. It can measure various thermodynamic and kinetic parameters, such as specific heat capacity, heat of reaction, heat of transition Wait. [0003] From the experiment of sulfate on concrete erosion, we can know that the erosion mechanism is that the expansion products dihydrate gypsum and ettringite lead to the destruction of concrete. The...

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Problems solved by technology

However, the calculation result of the calculation program that comes with DSC only gives a peak at 131.77°C to represent the enthalpy change value of ettringite, which not only ignores the fact that the double peaks belong to ettringite, but also does not give the peak at about 170°C. The enthalpy change value of dihydrate gypsum, this result is not consistent with the phenomenon of dihydrate gypsum observed in the experiment

Therefore, it can be considered that the peak of dihydrate gypsum and the peak of ettringite overlap in a large area, which leads to the inability to correctly identify the DSC built-in calculation program

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