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Sushil dta

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Sushil Kumar

Differential thermal analysis (DTA) measures the temperature difference between a sample and an inert reference material as they are heated or cooled under identical conditions. DTA can detect physical or chemical changes in materials by identifying endothermic or exothermic reactions as peaks on a thermogram. The technique is used to determine phase changes, melting points, heat capacity, and decomposition temperatures of materials. Common applications of DTA include identification of materials, pharmaceutical analysis, and studying reactions in cement, minerals, foods, bones, and archaeological samples.

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DIFFERENTIAL THERMAL ANALYSIS (DTA) Presented By;Sushil kumar 1205068
Sushil dta
Thermal Analysis Techniques It is a group of techniques in which a physical property is measured as a function of temperature, while the sample is subjected to a controlled temperature programme (heating, cooling or isothermal).
Thermal Analysis Techniques & Types of thermal analysis : Differential Thermal Analysis (DTA) temperature difference Differential Scanning Calorimetry (DSC) heat difference Thermogravimetric analysis(TGA)-change in weight
What is DTA ? Involves the technique of recording the difference in temperature between the Test and Reference material time being constant for both. Hence the Differential Thermogram consists record of difference in Temperatures.
DTA Principle: DTA is a technique in which the difference between the sample and reference material is measured as a sample of furnace temp(t) while sample and ref. materials are subjected to a controlled programme. Usually a tempr programme involves heating the sample and ref. material in such a way that tempr of sample (ts) increases linerally with time.
In Differential Thermal Analysis, the temperature difference that develops between a sample and an inert reference material is measured, when both are subjected to identical heat - treatments. The related technique of Differential Scanning Calorimetry relies on differences in energy required to maintain the sample and reference at an identical temperature.
INTRODUCTION(DTA) This is a comparison method Analytical method for recording the difference in temperature (T) b/w a substance and an inert reference material as a function of temperature or time Any transformation change in specific heat or an enthaply of transition can be detected by DTA
In DTA both test sample & an inert reference material (alumina) controlled heating or cooling programming If zero temperature difference b/w sample & reference material sample does not undergo any chemical or physical change. If any reaction takes place temperature difference (T) will occur b/w sample & reference material
Thermogram A differential thermogram consists of a record of the difference in sample and reference themperature(T) plotted as a function of time t, sample temperature(Ts), reference temperature(Tr) or furnace temperature(Tf). In most of the cases, physical changes give rise to endothermic curves, whereas chemical reactions give rise to exothermic peaks.
DTA CURVE A DTA curve can be used as a finger print for identification purposes, for example, in the study of clays where the structural similarity of different forms renders diffraction experiments difficult to interpret.
Factors affecting DTA curve A] Environmental factors B] Instrumental factors i] Sample holder ii] Differential temperature sensing device iii] Furnace characteristics iv] Temperature- programmer controller v] Thermal Regime vi] Recorder C] Sample factors 1] Physical 2] Chemical
T VS Temp. Sharp Endothermic changes in crystallanity or fusion Broad endotherms - dehydration reaction Physical changes usually result in endothermic curves Chemical reactions are exothermic
Instrumentation A differential thermal analysis is composed of five basic components, namely : 1} Furnace 2} Sample holder 3} temperature programmer/sensors 4} Recorders 5}Atmosphere control and Amplifiers .
Sushil dta
1} Furnace Assembly The furnace is of high temperature electric tube,max temperature upto 1000 尊c can be provided.
It is a tube containing sample ,a similar tube containing reference material such as alumina or silicon carbide which are inert substances .This tube are inserted into a metallic heater block.Thermocouple are inserted in sample & reference tube. In low temp range termocouple are used & other detector such as prt and thermistor can also be used.
It provides smooth heating or cooling at a linear rate by changing the voltage through heating component. Modern DTA instruments incorporate electronic temp controller in which the signal from thermocouple in furnace is compared electically against ref.potential which can be programmed to corresponds to a variety of heating modes & heating rates.
It is a dual pen strip chart recorder usually t change in temperature is recorded at y-axis & Tz furnace temp is x-axis.
5} Atmosphere control and Amplifiers For some type of samples the atmosphere must be controlled to suppress and undesirable reaction such as oxidation by flowing an inert gas. AMPLIFIERS;It is used for amplification of signals obtained from (T) c.It is gain and low noise circuit.
Differential Thermal Analysis advantages: instruments can be used at very high temperatures instruments are highly sensitive characteristic transition or reaction temperatures can be accurately determined disadvantages: uncertainty of heats of fusion, transition, or reaction estimations is 20-50% DTA
Physical Chemistry 1. Heat of a Reaction 2. Specific Heat of substance like Naphthalene. 3. Thermal Diffusivity of samples Analytical Chemistry 1. Identification of Products since no two products have identical curves. 2. Determination of Melting point.
Applications Of DTA; 1.A DTA curve can be used only as a finger print for identification purpose but usually the applications of this method are the determination of phase diagrams,heat change measurements & decomposition in
Applications of DTA. 2.DTA is widely used in medical(pharmaceutical)and food industries. 3.DTA may be used in cement chemistry,mineralogical research and enviromental studies. 4.DTA curves may also be used to date bone remains or to study archaeological materials.
Sushil dta
Sushil dta

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Sushil dta

  • 3. Thermal Analysis Techniques It is a group of techniques in which a physical property is measured as a function of temperature, while the sample is subjected to a controlled temperature programme (heating, cooling or isothermal).
  • 4. Thermal Analysis Techniques & Types of thermal analysis : Differential Thermal Analysis (DTA) temperature difference Differential Scanning Calorimetry (DSC) heat difference Thermogravimetric analysis(TGA)-change in weight
  • 5. What is DTA ? Involves the technique of recording the difference in temperature between the Test and Reference material time being constant for both. Hence the Differential Thermogram consists record of difference in Temperatures.
  • 6. DTA Principle: DTA is a technique in which the difference between the sample and reference material is measured as a sample of furnace temp(t) while sample and ref. materials are subjected to a controlled programme. Usually a tempr programme involves heating the sample and ref. material in such a way that tempr of sample (ts) increases linerally with time.
  • 7. In Differential Thermal Analysis, the temperature difference that develops between a sample and an inert reference material is measured, when both are subjected to identical heat - treatments. The related technique of Differential Scanning Calorimetry relies on differences in energy required to maintain the sample and reference at an identical temperature.
  • 8. INTRODUCTION(DTA) This is a comparison method Analytical method for recording the difference in temperature (T) b/w a substance and an inert reference material as a function of temperature or time Any transformation change in specific heat or an enthaply of transition can be detected by DTA
  • 9. In DTA both test sample & an inert reference material (alumina) controlled heating or cooling programming If zero temperature difference b/w sample & reference material sample does not undergo any chemical or physical change. If any reaction takes place temperature difference (T) will occur b/w sample & reference material
  • 10. Thermogram A differential thermogram consists of a record of the difference in sample and reference themperature(T) plotted as a function of time t, sample temperature(Ts), reference temperature(Tr) or furnace temperature(Tf). In most of the cases, physical changes give rise to endothermic curves, whereas chemical reactions give rise to exothermic peaks.
  • 11. DTA CURVE A DTA curve can be used as a finger print for identification purposes, for example, in the study of clays where the structural similarity of different forms renders diffraction experiments difficult to interpret.
  • 12. Factors affecting DTA curve A] Environmental factors B] Instrumental factors i] Sample holder ii] Differential temperature sensing device iii] Furnace characteristics iv] Temperature- programmer controller v] Thermal Regime vi] Recorder C] Sample factors 1] Physical 2] Chemical
  • 13. T VS Temp. Sharp Endothermic changes in crystallanity or fusion Broad endotherms - dehydration reaction Physical changes usually result in endothermic curves Chemical reactions are exothermic
  • 14. Instrumentation A differential thermal analysis is composed of five basic components, namely : 1} Furnace 2} Sample holder 3} temperature programmer/sensors 4} Recorders 5}Atmosphere control and Amplifiers .
  • 16. 1} Furnace Assembly The furnace is of high temperature electric tube,max temperature upto 1000 尊c can be provided.
  • 17. It is a tube containing sample ,a similar tube containing reference material such as alumina or silicon carbide which are inert substances .This tube are inserted into a metallic heater block.Thermocouple are inserted in sample & reference tube. In low temp range termocouple are used & other detector such as prt and thermistor can also be used.
  • 18. It provides smooth heating or cooling at a linear rate by changing the voltage through heating component. Modern DTA instruments incorporate electronic temp controller in which the signal from thermocouple in furnace is compared electically against ref.potential which can be programmed to corresponds to a variety of heating modes & heating rates.
  • 19. It is a dual pen strip chart recorder usually t change in temperature is recorded at y-axis & Tz furnace temp is x-axis.
  • 20. 5} Atmosphere control and Amplifiers For some type of samples the atmosphere must be controlled to suppress and undesirable reaction such as oxidation by flowing an inert gas. AMPLIFIERS;It is used for amplification of signals obtained from (T) c.It is gain and low noise circuit.
  • 21. Differential Thermal Analysis advantages: instruments can be used at very high temperatures instruments are highly sensitive characteristic transition or reaction temperatures can be accurately determined disadvantages: uncertainty of heats of fusion, transition, or reaction estimations is 20-50% DTA
  • 22. Physical Chemistry 1. Heat of a Reaction 2. Specific Heat of substance like Naphthalene. 3. Thermal Diffusivity of samples Analytical Chemistry 1. Identification of Products since no two products have identical curves. 2. Determination of Melting point.
  • 23. Applications Of DTA; 1.A DTA curve can be used only as a finger print for identification purpose but usually the applications of this method are the determination of phase diagrams,heat change measurements & decomposition in
  • 24. Applications of DTA. 2.DTA is widely used in medical(pharmaceutical)and food industries. 3.DTA may be used in cement chemistry,mineralogical research and enviromental studies. 4.DTA curves may also be used to date bone remains or to study archaeological materials.

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