What are the factors that affect the differential thermal analysis curve

The main factors influencing differential thermal analysis are as follows:

Heating rate The lower heating rate can make the baseline drift smaller, and the resolution of the curve is high, but the measurement time is long. However, the higher the heating rate, the baseline drift is more significant, and the resolution of the curve decreases.

Atmosphere and pressure For the reaction of gaseous substances and the reaction of substances that are easily oxidized, the appropriate atmosphere and pressure j can be determined to obtain better experimental results.

Reference material As a reference material, it is required to maintain thermal stability within the measurement temperature range, and is generally used. A-A1203, MGO, SI02 and nickel metal, etc. When selecting, the government tries to use substances that are consistent with the specific heat capacity, heat frequency and particle size of the sample to improve the accuracy.

Specimen Handling Smaller specimen grain sizes can improve thermal conductivity conditions, but too fine can disrupt the specimen cell or cause it to break down. The amount of sample is related to the magnitude of the thermal effect and the inter-peak primordial. Generally, the dosage should not be too large, otherwise the resolution of the curve will be reduced.

Due to the difference in thermal analysis, it is mainly related to whether the specimen has undergone a state change with thermal effects. Therefore, it cannot be used to determine the nature of the change. That is, whether the change is a physical or chemical change, whether it is done in one step or in a step, and whether there is a change in mass.

The nature and mechanism of change need to be further determined by other methods. Another characteristic of differential thermal analysis is that it is still a dynamic calorimetry in nature, i.e., the temperature conditions at the time of calorimetry are not constant but variable. Therefore, the system is not in equilibrium during the measurement process, and the measured results are different from those measured under thermodynamic equilibrium.

1.Selection of references.

2.Rate of warming.

3.The influence of the ambient atmosphere.

4.Pretreatment and dosage of the sample.

It's very familiar.,Yes, but it's not good.,Obviously, there's no mistake

Factors related to the nature of the sample, reference, diluent, dosage, particle size, packing state, etc., can also affect the experimental curve. The experimental conditions during the experiment, such as the setting heating rate and the atmosphere in the furnace, will also affect the baseline and experimental curve, and then involve the exothermic peak and the endothermic peak.

Factors influencing the thermogravimetric curve: equipment factors, operating factors, test conditions, and the nature of the sample, etc.

The thermogravimetric curve is the curve of the mass change with temperature in the heating process of the sample obtained by the thermal balance in the thermal analysis process, which is generally used in combination with the differential thermal curve, and the reaction degree of the sample at a certain temperature and the corresponding substance content can be understood through the analysis and calculation of the thermogravimetric curve, which is a commonly used thermal analysis method. The main factors affecting the thermogravimetric curve are sample size, heating rate, atmosphere, buoyancy effect, volatile condensation, specimen dish, etc.

Factors influencing the differential heat profile: selection of reference material, heating rate, influence of ambient atmosphere, sample pretreatment and dosage, etc.

Differential thermal analysis is an important thermal analysis method, which refers to a testing technique that measures the relationship between the temperature difference between substances and reference materials and temperature or time under programmed temperature control. This method is widely used to determine the characteristic temperature of substances during thermal reactions and the heat absorbed or released, including physical or chemical reactions such as phase transformation, decomposition, compounding, coagulation, dehydration, and evaporation. It is widely used in inorganic, silicate, ceramics, mineral metals, aerospace temperature-resistant materials and other fields, and is an important instrument for thermal analysis of inorganic, organic, especially polymers, FRP, etc.

A differential thermal analyzer is not the same as a differential scanning calorimeter!

The difference is that the differential thermal analyzer measures the value of the heat emitted or absorbed by the sample; A differential scanning calorimeter, on the other hand, measures the difference in energy (or power) of a sample relative to a reference substance (e.g., alumina, which has no thermal effect in the test temperature range, etc.) per unit time.

Both abscissa is temperature. The ordinate, the differential heat analysis spectrum is the thermal effect (endothermic or exothermic), if there is a thermal effect, there will be a peak, if the design is designed so that the endothermic peak is upward, the exothermic peak is downward; If there is no thermal effect between the sample and the reference material, the differential scanning calorimeter spectrum is a horizontal straight line; If the specimen has a thermal effect, because the selected reference material has no thermal effect, the difference in the thermal effect energy or power of the specimen is shown in the differential scanning calorimetry spectrum.