Thermal balance is the most important part of the STA instrument. The
principle of thermal balance is similar with which of balance. It can measure the weigh of sample continuously in the condition of heating and record the relationship between changes of sample weight and temperature continuously.
The difference between TG and DTG is that signals are handled differently. DTG curve is peaky curve and the point at the peak maximum is corresponding to the inflection point of TG curve. The rate of the reaction.
On and OFF
Program
1 Turn on/Off all instruments
2 Open/Close the gas cylinder 3 Connect/ Disconnect the computer
1 Initial state
2 Purge gas
3 Temperature program with gas switch
No.4 etc.
•Maintenance
1. Use ethanol or acetone to wipe the inside surface of the furnace . 2. Run the heating program to 900℃ with no sample and use air as the purge gas. 3.Wash the cylinders using ultrasonic cleaner, the heat them at 900℃. 4. Replace the glass cotton piece.
• Combination with other instruments
TG-MS、TG-GC、TG-FTIR etc.
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Introduction
• Mass
Thermogravimetry (TG) Differential Thermogravimetry (DTG)
• Temperature
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• DTG
Differential thermogravimetric curve (DTG curve) is obtained by differential processing of TG curve.
dm/dt = f (T或t)
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Principle
• Thermal balance
Synchronous Thermal Analyzer
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同步热分析仪（STA）
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1
Contents
1 2 3
Introduction Principle Structure
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5
Operation & Maintenance Application
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Application
TG
DTG
1. Process and mechanism of thermal decomposition reaction. 2. Crystal water, absorbed water and water removal. 3. Reactions between solid and gas. 4. Analysis of composition of substances. And so on.
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Introduction
• Thermal Analysis (TA)
STA is based on thermal analysis
• 1915 Japan
本多光太郎 thermo-balance （热天平）
• Recent years
controlled by computer 、high automation and more precise
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Structure
Mass flow meter
Signal detection and record system
STA
同步热分析仪
Thermal balance
Heating furnace
Control system of temperature
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Operation
Weighing samples 1 Special crucible 2 10± 0.1mg 3 Zero sample Weigh sample
• 3.这台仪器可否测热量变化，与DSC的区别是什么？
答：可以，在数据中选择热量即可。数据与DSC基本相同，可以得 到物质的吸、放热数据。
• 4.热重谱图如何分析？
答：热重谱图应包括 TG、DTG和热量曲线。TG曲线是阶梯式的， 应按阶段分析；DTG曲线是峰形曲线，可以观察最大峰值；热量曲线可 以分析样品的吸、放热性质。这三条曲线应该配合起来一起分析。
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Maintenance
attention
No.1 Keep the outer surface of the crucible clean. No.2 Don’t sprinkle the sample on the outside. No.3 Don’t turn off the instrument when the sample temperature is higher than 100℃.
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Questions & answers
• 1.使用这台仪器时是否需要参比物？
答：不需要。仪器中只有一个天平，只需将样品放入其中即可。
• 2.升温速率范围是多少，不同升温速率对TG有什么影响？
答：升温速率5-100℃/min。不同的升温速率对样品的传热有影响， 升温速率越快，样品温度与设定温度之间的延迟越大，在某一温度段的 停留时间越短。 通常升温速率在10-30℃/min比较合适。
Heating-curve Determination (HCD) Differential Thermal Analysis (DTA)
• Enthalpy
Differential Scanning Calorimetry (DCS)
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Principle
• TG
At a certain temperature, the weight of the material will change because some ingredients of the substance will be decomposed or removed. TG is used to measure the relationship between the weight of material and temperature changes under program-controlled temperature change. Thermogravimetric curve is recorded, quality as the ordinate and temperature as abscissa.