Differential thermal analysis

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Differential thermal analysis
AcronymDTA
Classification Thermal analysis
Other techniques
Related Differential scanning calorimetry
Isothermal microcalorimetry
Dynamic mechanical analysis
Thermomechanical analysis
Thermogravimetric analysis
Dielectric thermal analysis

Differential thermal analysis (DTA) is a thermoanalytic technique that is similar to differential scanning calorimetry. In DTA, the material under study and an inert reference are made to undergo identical thermal cycles, (i.e., same cooling or heating programme) while recording any temperature difference between sample and reference. [1] This differential temperature is then plotted against time, or against temperature (DTA curve, or thermogram). Changes in the sample, either exothermic or endothermic, can be detected relative to the inert reference. Thus, a DTA curve provides data on the transformations that have occurred, such as glass transitions, crystallization, melting and sublimation. The area under a DTA peak is the enthalpy change and is not affected by the heat capacity of the sample.

Contents

Apparatus

A DTA consists of a sample holder, thermocouples, sample containers and a ceramic or metallic block; a furnace; a temperature programmer; and a recording system. The key feature is the existence of two thermocouples connected to a voltmeter. One thermocouple is placed in an inert material such as Al2O3, while the other is placed in a sample of the material under study. As the temperature is increased, there will be a brief deflection of the voltmeter if the sample is undergoing a phase transition. This occurs because the input of heat will raise the temperature of the inert substance, but be incorporated as latent heat in the material changing phase. [2] It consist of inert environment with inert gases which will not react with sample and reference. Generally helium or argon is used as inert gas.

Today's instruments

In today's market most manufacturers don't make true DTA systems but rather have incorporated this technology into thermogravimetric analysis (TGA) systems, which provide both mass loss and thermal information. With today's advancements in software, even these instruments are being replaced by true TGA-DSC instruments that can provide the temperature and heat flow of the sample, simultaneously with mass loss.

Applications

A DTA curve can be used only as a finger print for identification purposes but usually the applications of this method are the determination of phase diagrams, heat change measurements and decomposition in various atmospheres.

DTA is widely used in the pharmaceutical [3] [4] [5] and food industries. [6] [7] [8] [9]

DTA may be used in cement chemistry, [10] mineralogical research [11] and in environmental studies. [12]

DTA curves may also be used to date bone remains [13] or to study archaeological materials. [14] [15] Using DTA one can obtain liquidus & solidus lines of phase diagrams.

Related Research Articles

<span class="mw-page-title-main">Differential scanning calorimetry</span> Thermoanalytical technique

Differential scanning calorimetry (DSC) is a thermoanalytical technique in which the difference in the amount of heat required to increase the temperature of a sample and reference is measured as a function of temperature. Both the sample and reference are maintained at nearly the same temperature throughout the experiment. Generally, the temperature program for a DSC analysis is designed such that the sample holder temperature increases linearly as a function of time. The reference sample should have a well-defined heat capacity over the range of temperatures to be scanned. Additionally, the reference sample must be stable, of high purity, and must not experience much change across the temperature scan. Typically, reference standards have been metals such as indium, tin, bismuth, and lead, but other standards such as polyethylene and fatty acids have been proposed to study polymers and organic compounds, respectively.

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<span class="mw-page-title-main">Thermogravimetric analysis</span> Thermal method of analysis

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<span class="mw-page-title-main">Nickel(II) sulfate</span> Chemical compound

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<span class="mw-page-title-main">Ammonium tetrathiomolybdate</span> Chemical compound

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<span class="mw-page-title-main">Iron(II) oxalate</span> Chemical compound

Ferrous oxalate (iron(II) oxalate) are inorganic compound with the formula FeC2O4(H2O)x where x is 0 or 2. These are orange compounds, poorly soluble in water.

<span class="mw-page-title-main">Huntite</span> Carbonate mineral

Huntite is a carbonate mineral with the chemical formula Mg3Ca(CO3)4. Huntite crystallizes in the trigonal system and typically occurs as platy crystals and powdery masses. For most of recorded history its main use was as a white pigment. Today the most common industrial use of huntite is as a natural mixture with hydromagnesite as a flame retardant or fire retardant additive for polymers.

<span class="mw-page-title-main">Isothermal microcalorimetry</span> Measuring versus elapsed time the net rate of heat flow

Isothermal microcalorimetry (IMC) is a laboratory method for real-time monitoring and dynamic analysis of chemical, physical and biological processes. Over a period of hours or days, IMC determines the onset, rate, extent and energetics of such processes for specimens in small ampoules at a constant set temperature.

Uranyl metaphosphate is a compound of uranium, phosphorus, and oxygen. It is one of the phosphates of uranium with the formula [UO2(PO3)2]n. This long-chain compound is formed via the thermal decomposition of UO2(H2PO4)2·3H2O. Double salts such as NaUO2(PO3)3 and CsUO2(PO3)3 are known.

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<span class="mw-page-title-main">Bismuth oxynitrate</span> Chemical compound

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<span class="mw-page-title-main">Bismuth(III) nitrate</span> Chemical compound

Bismuth(III) nitrate is a salt composed of bismuth in its cationic +3 oxidation state and nitrate anions. The most common solid form is the pentahydrate. It is used in the synthesis of other bismuth compounds. It is available commercially. It is the only nitrate salt formed by a group 15 element, indicative of bismuth's metallic nature.

<span class="mw-page-title-main">Magnesium formate</span> Chemical compound

Magnesium formate is a magnesium salt of formic acid. It is an inorganic compound. It consists of a magnesium cation and formate anion. It can be prepared by reacting magnesium oxide with formic acid. The dihydrate is formed when crystallizing from the solution. The dihydrate dehydrates at 105 °C to form anhydrate, then decomposes at 500 °C to produce magnesium oxide. Magnesium formate can be used for organic syntheses.

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<span class="mw-page-title-main">Neodymium nitrate</span> Inorganic chemical compound

Neodymium nitrate is an inorganic compound with the formula Nd(NO3)3·(x(H2O). It is typically encountered as the hexahydrate, Nd(NO3)3·6H2O, which is more accurately formulated as [Nd(NO3)3(H2O)4].2H2O to reflect the crystal structure. It decomposes to NdONO3 at elevated temperature.

<span class="mw-page-title-main">Neodymium bismuthide</span> Chemical compound

Neodymium bismuthide or Bismuth-Neodymium is a binary inorganic compound of neodymium and bismuth with the formula NdBi. It forms crystals.

<span class="mw-page-title-main">Europium(III) phosphate</span> Chemical compound

Europium(III) phosphate is one of the phosphates of europium, with the chemical formula of EuPO4. Other phosphates include europium(II) phosphate (Eu3(PO4)2) and europium(II,III) phosphate (Eu3Eu(PO4)3).

<span class="mw-page-title-main">Caesium permanganate</span> Chemical compound

Caesium permanganate is the permanganate salt of caesium, with the chemical formula CsMnO4.

References

  1. ↑ Bhadeshia, H.K.D.H. "Thermal analyses techniques. Differential thermal analysis" (PDF). University of Cambridge, Material Science and Metallurgy. Retrieved 2023-09-17.
  2. ↑ Robert Bud, Deborah Jean Warner (1998). Instruments of Science. Taylor & Francis. pp. 170–171. ISBN   9780815315612.
  3. ↑ Ferrer, S.; Borras, J.; Martin-Gil, J.; Martin-Gil, F.J. (1989). "Thermal studies on sulphonamide derivative complexes". Thermochimica Acta. 147 (2). Elsevier BV: 321–330. doi:10.1016/0040-6031(89)85187-1. ISSN   0040-6031.
  4. ↑ Ferrer, S.; Borras, J.; Martin-Gil, J.; Martin-Gil, F.J. (1989). "Thermal decomposition of sulphonamide derivative complexes". Thermochimica Acta. 153. Elsevier BV: 205–220. doi:10.1016/0040-6031(89)85434-6. ISSN   0040-6031.
  5. ↑ Alzuet, G.; Ferrer, S.; Borrás, J.; Martín-Gil, J.; Martín-Gil, F.J. (1991). "Thermal studies of sulphonamide derivative complexes". Thermochimica Acta. 185 (2). Elsevier BV: 315–333. doi:10.1016/0040-6031(91)80053-l. ISSN   0040-6031.
  6. ↑ BERGER, K. G.; AKEHURST, E. E. (2007-06-28). "Some applications of differential thermal analysis to oils and fats". International Journal of Food Science & Technology. 1 (3). Wiley: 237–247. doi:10.1111/j.1365-2621.1966.tb01810.x. ISSN   0950-5423.
  7. ↑ C. Ramos-Sanchez, M; Rey, F.J.; L. Rodriguez, M; Martin-Gil, F.J.; Martin-Gil, J. (1988). "DTG and dta studies on typical sugars". Thermochimica Acta. 134. Elsevier BV: 55–60. doi:10.1016/0040-6031(88)85216-x. ISSN   0040-6031.
  8. ↑ Rey, F.J.; Ramos-Sanchez, M.C.; Rodriguez-Mendez, M.L.; Martin-Gil, J.; Martin-Gil, F.J. (1988). "DTG and DTA studies on sugar derivatives". Thermochimica Acta. 134. Elsevier BV: 67–72. doi:10.1016/0040-6031(88)85218-3. ISSN   0040-6031.
  9. ↑ L. Rodriguez-Mendez, Ma; Rey, F.J.; Martin-Gil, J.; Martin-Gil, F.J. (1988). "DTG and DTA studies on amino acids". Thermochimica Acta. 134. Elsevier BV: 73–78. doi:10.1016/0040-6031(88)85219-5. ISSN   0040-6031.
  10. ↑ Ramachandran V.S. “Applications of differential thermal analysis in cement chemistry”. Chap. V, Chemical Publishing Co., Inc., New York (1969), 92.
  11. ↑ Smykatz-Kloss, W. (1982). "Application of differential thermal analysis in mineralogy". Journal of Thermal Analysis. 23 (1–2). Springer Science and Business Media LLC: 15–44. doi:10.1007/bf01908484. ISSN   0022-5215. S2CID   93921297.
  12. ↑ Smykatz-Kloss, W.; Heil, A.; Kaeding, L.; Roller, E. (1991). "Thermal analysis in environmental studies". Thermal Analysis in the Geosciences. Lecture Notes in Earth Sciences. Vol. 38. Berlin/Heidelberg: Springer-Verlag. pp. 352–367. doi:10.1007/bfb0010275. ISBN   3-540-54520-4.
  13. ↑ Villanueva, PrE; Girela, F.; Castellanos, M. (1976). "The application of differential thermal analysis and thermogravimetric analysis to dating bone remains". Journal of Forensic Sciences. 21 (4): 822–830. doi:10.1520/JFS10567J. PMID   184235.
  14. ↑ Misiego-Tejeda J.C., Marcos-Contreras G.J., Sarabia Herrero F.J., Martín Gil J. and Martín Gil F.J. "Un horno doméstico de la primera Edad del Hierro de "El Soto de Medinilla" (Valladolid) y su análisis por ATD". BSAA (University of Valladolid) 1993, LIX, 89 111.
  15. ↑ KINGERY, W. D. (1974). "A note on the differential thermal analysis of archaeological ceramics". Archaeometry. 16 (1). Wiley: 109–112. doi:10.1111/j.1475-4754.1974.tb01099.x. ISSN   0003-813X.
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