Differential thermal analyzer is a thermal analytical instrument that tests the thermal effect of substances in the process of heating or cooling, which can study the relationship between the physical and chemical change rate of substances and temperature, as well as the characteristics of some physical and chemical properties of substances under the action of thermal energy. The functional relationship between the temperature difference and the temperature between the substance and the reference substance can also be measured under the programmed temperature control.

The main principle:

It is a function of measuring the temperature difference between the sample and the reference material and the ambient temperature under the programmed temperature control condition. Under the control of the temperature program, in the process of heating (cooling) of the sample, where there is a physical change or chemical change, there will be an endothermic (or exothermic) effect. If there is no physical change and chemical change of inert material in the experimental temperature range as a reference, there will be a temperature difference between the sample and the reference. The curve of temperature difference with temperature is called differential heat curve or DTA curve.

The general differential thermal analyzer is composed of heating system, temperature control system, signal amplification system, differential thermal system and recording system. Some models also include atmosphere control systems and pressure control systems:

Principle and structure of differential thermal analyzer

1. Heating system: Provide the temperature conditions required for testing, and the heating elements and core materials in the system are selected according to the different test ranges.

2, temperature control system: used to control the heating conditions during the test, such as heating rate, temperature test range, etc.

3, signal amplification system: through the DC amplifier to the differential thermocouple generated by the weak thermoelectromotive force amplification, increase, output, so that the instrument can more accurately record the test signal.

4, differential heat system: is the core part of the whole device, composed of sample chamber, sample crucible, thermocouple and so on. Among them, thermocouple is the key component, which is not only a temperature measurement tool, but also a signal transmission tool, which can be selected according to the test requirements.

5, recording system: the early use of double-pen recorder for automatic recording, has been able to use computer for automatic control and recording, and can analyze the test results, which provides great convenience for experimental research.