Conditions of formation and some properties of zirconium oxycarbides

Kosolapova, T. Ya.; Fedorus, V. B.; Panasyuk, A. D.; Kozina, Goran

doi:10.1007/bf00802878

Cited by 10 publications

(11 citation statements)

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“…In comparison with the diffraction peak of the stoichiometric carbide, the (511) peak is slightly shifted toward the high angles. This result on oxycarbides has already been observed in the literature and is characteristic of the substitution of carbon by oxygen atoms within the carbide lattice. Indeed, the covalent radius of oxygen ( r O =0.64 Å) being lower than that of carbon ( r C =0.74 Å) this substitution results in the decreasing of the cell parameter.…”

Section: Resultssupporting

confidence: 79%

Experimental investigation and thermodynamic evaluation of the C–Hf–O ternary system

et al. 2017

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The first part of this work is dedicated to an experimental investigation of the C-Hf-O system and in particular to the stability domain of the HfC x O y oxycarbide phase formed through the carbothermal reduction in HfO 2 by carbon black at 1650 and 1750°C. This study which has been carried out by coupling chemical elemental analysis of powder with a structural approach by X-ray powder diffraction and Transmission Electron Microscopy (TEM) shows that the solid solution of the oxygen ranges from HfC 0.98AE0.01 O 0.02AE0.03 to HfC 0.90AE0.01 O 0.10AE0.03 at 1650°C and from HfC 0.97AE0.01 O 0.03AE0.03 to HfC 0.89AE0.01 O 0.11AE0.03 at 1750°C. It was then concluded that contrary with earlier previous results from the literature, the stability field of the solid solution is very limited and not very sensitive to temperature. This behavior is also in contrast with results obtained on the ZrC x O y oxycarbide which shows an isostructural form of HfC x O y . The second part of the paper reports on the first modeling of the ternary thermodynamic diagram of the C-Hf-O system by the CALPHAD method. The accurate data experimentally obtained on the solid solution were integrated as diagrammatic data for the calculation. The modeling was based on from already published binary assessments after a selection of compatible binary models and the description of the HfC x O y solid solution was then added and optimized using the data of this work. As a result, a set of coherent parameters has been obtained, allowing to calculate isothermal sections of this C-Hf-O ternary system. K E Y W O R D Soxycarbides, solid solutions, thermodynamics, transmission electron micros, X-ray methods

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Section: Resultssupporting

confidence: 79%

Experimental investigation and thermodynamic evaluation of the C–Hf–O ternary system

et al. 2017

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“…In the nonstoichiometric ZrC x , the oxygen atoms can occupy the carbon vacancies or replace the carbon atoms to form an oxycarbide phase of ZrC x O y . − The occupation of carbon vacancies or the substitution of C with O does not modify the rocksalt structure. − The oxycarbide of ZrC x O y is thus isostructural to ZrC x with the similar cell parameters. Similar to ZrC x , ZrC x O y is also able to exist over a wide range of nonstoichiometry, and its lattice parameters depend on the content of oxygen .…”

Section: Resultsmentioning

confidence: 99%

Low-Temperature Diffusion of Oxygen through Ordered Carbon Vacancies in Zr₂C_x: The Formation of Ordered Zr₂C_xO_y

Xiang

Liu

et al. 2012

Inorg. Chem.

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Investigations are performed on low-temperature oxygen diffusion in the carbon vacancy ordered ZrC(0.6)and thus induced formation of the oxygen atom ordered ZrC(0.6)O(0.4). Theoretically, a superstructure of Zr(2)CO can be constructed via the complete substitution of carbon vacancies with O atoms in the Zr(2)C model. In the ordered ZrC(0.6), the consecutive arrangement of vacancies forms the vacancy channels along some zone axes in the C sublattice. Through these vacancy channels, the thermally activated oxygen diffusion is significantly facilitated. The oxygen atoms diffuse directly into and occupy the vacancies, producing the ordered ZrC(0.6)O(0.4). Relative to the ordered ZrC(0.6), the Zr positions are finely tuned in the ordered ZrC(0.6)O(0.4) because of the ionic Zr-O bonds. Because of this fine adjustment of Zr positions and the presence of oxygen atoms, the superstructural reflections are always observable in a selected area electron diffraction (SAED) pattern, despite the invisibility of superstructural reflections in ZrC(0.6) along some special zone axes. Similar to the vacancies in ordered ZrC(0.6), the ordering arrangement of O atoms in the ordered ZrC(0.6)O(0.4) is in nanoscale length, thus forming the nano superstructural domains with irregular shapes.

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“…The Zr content was calculated from the ZrO 2 formed after a complete oxidation of ZrCO samples at temperatures above 1000 • C. Finally, the oxygen content was calculated as the residual mass after deduction of defined C and Zr masses from the initial ZrCO sample weight. 33,98 Henney et al 62 observed a high deviation of calculated oxygen content in samples analyzed using this method. Therefore, stoichiometry determination using this method could have limitations.…”

Section: Characterization Methodsmentioning

confidence: 94%

“…Zirconium oxycarbides have been considered hightemperature materials for various applications, 114 including nonferrous metallurgy (Figure 23 98 ), or as ultralight porous ceramics with superior mechanical…”

Section: Applicationsmentioning

confidence: 99%

Zirconium oxycarbides and oxycarbonitrides: A review

Kucheryavaya

Lenčéš

Šajgalı́k

et al. 2022

Int J Applied Ceramic Tech

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Zirconium oxycarbides and zirconium oxycarbonitrides are high-temperature ceramic materials with great potential for applications in advanced technologies due to their good refractoriness, mechanical and thermoelectric properties, and corrosion resistance. The properties of ZrCO(N) materials strongly depend on their composition. However, the stoichiometry of stable ZrCO(N) compounds, synthesis chemistry, and thermodynamics of the proceeding reactions require clarification. This review comprehensively interprets data for ZrCO and ZrCON ceramics, including studies that may not have been addressed in prior reviews. It summarizes the state-of-the-art synthesis procedures involving reactions between commonly used zirconia, zirconium carbide, and carbon black, along with other zirconium sources widely used in the last few decades for the preparation of ZrCO(N) materials. The controversial reaction mechanisms of carbothermal reduction of zirconia and the role of CO gas in this process are discussed. The properties of ZrCO and ZrCON and their possible applications are also summarized.

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Conditions of formation and some properties of zirconium oxycarbides

Cited by 10 publications

References 1 publication

Experimental investigation and thermodynamic evaluation of the C–Hf–O ternary system

Experimental investigation and thermodynamic evaluation of the C–Hf–O ternary system

Low-Temperature Diffusion of Oxygen through Ordered Carbon Vacancies in Zr₂C_x: The Formation of Ordered Zr₂C_xO_y

Zirconium oxycarbides and oxycarbonitrides: A review

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Conditions of formation and some properties of zirconium oxycarbides

Cited by 10 publications

References 1 publication

Experimental investigation and thermodynamic evaluation of the C–Hf–O ternary system

Experimental investigation and thermodynamic evaluation of the C–Hf–O ternary system

Low-Temperature Diffusion of Oxygen through Ordered Carbon Vacancies in Zr2Cx: The Formation of Ordered Zr2CxOy

Zirconium oxycarbides and oxycarbonitrides: A review

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Low-Temperature Diffusion of Oxygen through Ordered Carbon Vacancies in Zr₂C_x: The Formation of Ordered Zr₂C_xO_y