An in-depth in situ IR study of the thermal decomposition of barium trifluoroacetate hydrate

Mosiadz, M.; Juda, K.L.; Hopkins, Simon C.; Sołoducho, Jadwiga; Glowacki, B.A.

doi:10.1016/j.tca.2010.11.004

Cited by 34 publications

(15 citation statements)

References 25 publications

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“…Pristine Ba-TFA dehydrates in a two-stage process that tapers off at 100 °C, Figure ; bottom left, and releases 2 mol H 2 O per mol of salt. This is in accordance with refs , . Acac-modified Ba-TFA behaves similarly, releasing an equivalent of 1 mol H 2 O in two steps finishing at 115 °C.…”

Section: Resultssupporting

confidence: 92%

“…After a long plateau without discernible mass loss, the thermal decomposition of the pristine material begins at 273 °C and ends at 324 °C as a two-stage process, which is similar to results in the literature. 19,20 The remaining mass after the first decomposition step suggests the formation of intermediate CF 3 COOBaF 19,20 before BaF 2 is ultimately formed. The pyrolysis of the acac-modified salt sets in slightly delayed at 279 °C.…”

Section: Thermal Decomposition Of Individual Precursorsmentioning

confidence: 99%

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Improving CSD-Grown REBCO Thin Films by ACAC Addition to the Precursor Solution

et al. 2022

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Gd0.5Y0.5Ba2Cu3O7–x thin films have been grown from solutions of metal trifluoroacetates dissolved in methanol. These precursor solutions are well suited for chemical solution deposition because of their good wettability and long shelf lives. This could allow for high reproducibility of metalorganic decomposition and film growth if not counteracted by the highly hygroscopic nature of the solutions. Exposure to moist air can result in significant absorption of water with detrimental effects on microstructural film integrity, making the solutions and as-deposited films difficult to handle. To overcome this issue, acetylacetone (acac) has been introduced to the solutions as an additive. The complexing nature of this agent leads to strong interactions with the salts of Cu and the rare earth elements, reducing the sensitivity to humidity significantly. Films grown from acac-containing solutions are considerably smoother and denser, which in turn leads to enhanced current-carrying capabilities. To investigate the role of acac and its impact on the microstructure and superconducting properties of the films, infrared spectroscopy and thermogravimetry coupled with differential thermal analysis have been performed on different types of solutions and films with and without acac. The microstructural features of the films have been thoroughly compared by scanning electron microscopy. The superconducting properties, T c and J c, have been measured by inductive and resistive techniques. Particular focus has been put on the film characteristics that develop with varying amounts of moisture in the process gas during the decomposition of the metalorganic compounds.

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Section: Resultssupporting

confidence: 92%

Section: Thermal Decomposition Of Individual Precursorsmentioning

confidence: 99%

Improving CSD-Grown REBCO Thin Films by ACAC Addition to the Precursor Solution

et al. 2022

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“…In the studies of the conventional 100% fluorine containing TFA-MOD solution, fluorine containing gaseous by-products were always detected during the pyrolysis step, indicating the loss of F atoms [24][25][26][27]. In this study, the fluorine content in the precursor solution was approximately the minimum requirement for the complete conversion of Ba content to BaF 2 .…”

Section: B In-situ Study Of Gaseous By-products During the Pyrolysismentioning

confidence: 66%

A low-fluorine solution with a 2:1 F/Ba mole ratio for the fabrication of YBCO films

Feng

Zhao

et al. 2014

Supercond. Sci. Technol.

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In the reported low-fluorine MOD-YBCO studies, the lowest F/Ba mole ratio of the precursor solution was 4.5. However, further lowering the F/Ba ratio is important according to the researches of YBCO thick film. On the other hand, the F/Ba ratio is necessary to be at least 2 for the full conversion of the Ba precursor to BaF2 to avoid the formation of BaCO3, which is detrimental to the superconducting performance. In this study, a novel solution with the F/Ba mole ratio of 2 was developed, in which the fluorine content was only about 10.3% of that used in the conventional TFA-MOD method. Attenuated total reflectance-Fourier transformed-infrared spectra(ATR-FT-IR) revealed that BaCO3 was remarkably suppressed in the as-pyrolyzed film and eliminated at 700 • C. Thus YBCO films with a critical current density (Jc) over 5 MA cm −2 (77 K, 0 T, 200 nm thickness) could be obtained on LAO single crystal substrates. In-situ FT-IR spectra showed that no obvious fluorinated gaseous by-products were detected in the pyrolysis step, which indicated that all of the F atoms might remain in the film as fluorides. X-ray diffraction (XRD) θ/2θ scan showed that BaF2, but neither YF3 nor CuF2, was detected in the films quenched at 400 -800 • C. The formation priority of BaF2 over YF3 and CuF2 was interpreted by the chemical equilibrium of the potential reactions. Our study could enlarge the synthesis window of the precursor solution for MOD-YBCO fabrication and open a gate to study the fluorine content in the precursor solution continuously and systematically.

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“…Oxide fluorides and oxides might be formed as additional phases if temperatures exceed 400 °C [25]. Gaseous fluorine-containing species liberated under these conditions are for example (CF 3 CO) 2 O, CF 3 COF, COF 2 , and CO x which were detected by MS and IR spectroscopy [26]. Evidence of difluoromethylene diradicals (:CF 2 ) as intermediate species of the decomposition of TFA was reported; these radicals play a major role as fluorinating agent during the thermal decomposition [23].…”

Section: Bottom-up Synthesis Of Nano Metal Fluorides: Mechanistic Ovementioning

confidence: 99%

Nano metal fluorides: small particles with great properties

2020

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The recently developed fluorolytic sol–gel route to metal fluorides opens a very broad range of both scientific and technical applications of the accessible high surface area metal fluorides, many of which have already been applied or tested. Specific chemical properties such as high Lewis acidity and physical properties such as high surface area, mesoporosity and nanosize as well as the possibility to apply metal fluorides on surfaces via a non-aqueous sol make the fluorolytic synthesis route a very versatile one. The scope of its scientific and technical use and the state of the art are presented.

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An in-depth in situ IR study of the thermal decomposition of barium trifluoroacetate hydrate

Cited by 34 publications

References 25 publications

Improving CSD-Grown REBCO Thin Films by ACAC Addition to the Precursor Solution

Improving CSD-Grown REBCO Thin Films by ACAC Addition to the Precursor Solution

A low-fluorine solution with a 2:1 F/Ba mole ratio for the fabrication of YBCO films

Nano metal fluorides: small particles with great properties

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