ChemInform Abstract: A Comparative Study of the Oxidation Resistance of Zirconium Carbide and Zirconium Oxide Carbide.

Barnier, P.; Thévenot, F.

doi:10.1002/chin.198937031

Cited by 3 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The oxidation of ZrC has been studied under several experimental conditions of temperature and pressure but a clear understanding has not yet been achieved due to the large numbers of variables that affect it, such as chemical composition of the initial material (C/Zr stoichiometry), porosity, or grain size …”

Section: Introductionmentioning

confidence: 99%

“…3,4 ZrC has better properties than other carbides such as a higher thermal conductivity and higher melting point, [5][6][7][8] however, a comprehensive database on its properties is not available and therefore its use is rarely considered. 9 The oxidation of ZrC has been studied [10][11][12][13][14][15][16][17][18][19] under several experimental conditions of temperature and pressure [10][11][12][13][14] but a clear understanding has not yet been achieved due to the large numbers of variables that affect it, such as chemical composition of the initial material (C/Zr stoichiometry), porosity, or grain size. 9,20 A mechanistic model recently proposed by Katoh et al 9 building on the model previously proposed by Shimada 21 showed as an initial stage the formation of an oxycarbide ZrO x C (1Àx) layer 9,10,22 prior to the formation of an oxide layer.…”

mentioning

confidence: 99%

See 1 more Smart Citation

Zirconium carbide oxidation: Kinetics and oxygen diffusion through the intermediate layer

et al. 2018

View full text Add to dashboard Cite

Oxidation of hot‐pressed ZrC was investigated in air in the 1073‐1373 K range. The kinetics were linear at 1073 K, whereas at higher temperature samples initially followed linear kinetics before undergoing rapid oxidation leading to a Maltese cross shape of the oxide. The linear kinetics at 1073 K was governed by inward oxygen diffusion through an intermediate layer of constant thickness between ZrC and ZrO2 which was comprised of amorphous carbon and ZrO2 nanocrystals. Diffusion of oxygen through the intermediate layer was measured to be 9 × 10−10 cm2 s−1 using 18O as a tracer in a double oxidation experiment in 16O/18O. Oxidation at 1073 and 1173 K produced samples made of m‐ZrO2 and either t‐ or c‐ZrO2 with an adherent intermediate layer made of amorphous carbon and ZrO2, whereas oxidation at 1273 and 1373 K produced samples with a voluminous oxide made of m‐ZrO2 showing a gap between ZrC and the oxide. A substoichiometric zirconia layer was found at the gap at 1273 K and no carbon uptake was detected in this layer when compared with the top oxide layer. The loss of the intermediate layer and the slowdown of the linear rate constant (g m−2 s−1) at 1273 K compared to 1173 K was correlated with the preferential oxidation of carbon at the intermediate layer which would leave as CO and/or CO2 leaving a gap between ZrC and substoichiometric zirconia.

show abstract

Section: Introductionmentioning

confidence: 99%

mentioning

confidence: 99%

Zirconium carbide oxidation: Kinetics and oxygen diffusion through the intermediate layer

et al. 2018

View full text Add to dashboard Cite

show abstract

“…in controlling phase contamination due to the solubility of oxygen and nitrogen in the ZrC x lattice. Additionally, the presence of oxygen in ZrC x lattice gives birth to the oxycarbide class of compounds where there is a direct substitution of carbon (or a carbon vacancy) by oxygen [17][18][19] . It is also possible for carbon or oxygen to occupy the octahedral interstitial vacancies of the Zr lattice 20,21 .…”

mentioning

confidence: 99%

On the stoichiometry of zirconium carbide

Gasparrini

Rana

Brun

et al. 2020

Sci Rep

View full text Add to dashboard Cite

the dependencies of the enhanced thermomechanical properties of zirconium carbide (Zrc x) with sample purity and stoichiometry are still not understood due to discrepancies in the literature. Multiple researchers have recently reported a linear relation between the carbon to zirconium atomic ratio (c/Zr) and the lattice parameter, in contrast with a more established relationship that suggests that the lattice parameter value attains a maximum value at a C/Zr ~ 0.83. In this study, the relationship between C/Zr atomic ratio and the lattice parameter is critically assessed: it is found that recent studies reporting the thermophysical properties of Zrc x have unintentionally produced and characterised samples containing zirconium oxycarbide. to avoid such erroneous characterization of Zrc x thermophysical properties in the future, we propose a method for the accurate measurement of the stoichiometry of ZrC x using three independent experimental techniques, namely: elemental analysis, thermogravimetric analysis and nuclear magnetic resonance spectroscopy. Although a large scatter in the results (Δc/Zr = 0.07) from these different techniques was found when used independently, when combining the techniques together consistent values of x in Zrc x were obtained. Zirconium carbide (ZrC) is a much-promising material, it has received increased interest recently as an alternative material to silicon carbide (SiC) in nuclear fuel applications 1,2 , in next-generation nuclear fusion reactors 3 , and also as an ultra-high-temperature ceramic to be used in ceramic-metal composite heat exchangers in concentrated solar power (CSP) plants 4,5. ZrC (here denoted as ZrC x) is typically non-stoichiometric as it can contain up to 50% of unoccupied carbon sites 6,7 , it has been found that deviations in the stoichiometry of ZrC x can severely affect its thermal and mechanical properties 8,9. Given its potential in high-temperature applications, it is extremely important to define a method that robustly determines its stoichiometry and purity. The purity of ZrC x should always be assessed as the presence of contaminants such as nitrogen or oxygen is detrimental for its performance. For example, if ZrC x is to be used as a nuclear fuel coating in a nuclear reactor, any nitrogen contamination should be avoided due to the production of radioactive 14 C from nitrogen 14 N inside the reactor 10. There are two common methods for defining the stoichiometry of ZrC x. The first one is to evaluate the C/Zr atomic ratio from the lattice parameter measured by X-ray diffraction (XRD) using the correlation published in Jackson & Lee 6. The second one is to quantify through the inert-gas fusion technique the carbon content in ZrC x and calculate the C/Zr atomic ratio assuming that the sample is free from impurities. Both techniques, however, have limitations and when used in standalone approaches can lead to erroneous stoichiometry estimations, as we will proceed to demonstrate later in this paper. The need for an established robust method to measure ...

show abstract

“…The wetting angle for Co and Ni is higher for ZrC x O y than for ZrC, which make zirconium oxycarbides more stable in liquid transition metals, Figure 23. Coefficient of thermal expansion (10 −6 K −1 ) 10 6.8 7.1-8.6 42 Thermal conductivity (W m −1 K −1 ) 2 2 1 3 -5 58 Electrical resistivity (Ω cm) However, it was reported that the oxidation of zirconium oxycarbides starts below 500 • C. 107,108 Zirconium oxycarbide already forms at 400-480 • C within 5-10 min as an intermediate product of the oxidation of ZrC forming ZrC 1−y O y . [109][110][111] Besides the diffusion process of oxygen in zirconium carbide, 23 generally, it is accepted that ZrC is completely oxidized upon reaching 1000 • C. 112 ZrC 0.625 O 0.500 and ZrC 0.571 O 0.143 phases formed at 1127 • C under pressure of oxygen P O2 = 10 −3 -10 −7 Pa. 22 Processes connected with the grain boundary diffusion of oxygen could play a role in the formation of zirconium oxycarbides.…”

Section: Properties Of Sintered Materialsmentioning

confidence: 99%

“…The wetting angle for Co and Ni is higher for ZrC x O y than for ZrC, which make zirconium oxycarbides more stable in liquid transition metals, Figure 23 98 . However, it was reported that the oxidation of zirconium oxycarbides starts below 500°C 107,108 . Zirconium oxycarbide already forms at 400–480°C within 5–10 min as an intermediate product of the oxidation of ZrC forming ZrC 1− y O y 109–111 .…”

Section: Ternary Compoundsmentioning

confidence: 99%

Zirconium oxycarbides and oxycarbonitrides: A review

Kucheryavaya

Lenčéš

Šajgalı́k

et al. 2022

Int J Applied Ceramic Tech

View full text Add to dashboard Cite

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.

show abstract

ChemInform Abstract: A Comparative Study of the Oxidation Resistance of Zirconium Carbide and Zirconium Oxide Carbide.

Cited by 3 publications

References 0 publications

Zirconium carbide oxidation: Kinetics and oxygen diffusion through the intermediate layer

Zirconium carbide oxidation: Kinetics and oxygen diffusion through the intermediate layer

On the stoichiometry of zirconium carbide

Zirconium oxycarbides and oxycarbonitrides: A review

Contact Info

Product

Resources

About