Solubility of Oxygen in ZrC

Sarkar, Suman; Miller, Alan D.; Mueller, J. I.

doi:10.1111/j.1151-2916.1972.tb13457.x

Cited by 55 publications

(33 citation statements)

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“…However, the ZrC x lattice parameter is affected by other factors such as crystallite size, strain, and partial occupancy of C vacancies by dissolved species such as O or N, meaning that XRD is not a definitive tool for determining C stoichiometry. The slight decrease in lattice parameter with increasing synthesis temperature was likely due to the removal of O or N from the ZrC x lattice or slight changes in C stoichiometry . Overall, the lattice parameters are consistent with carbon‐deficient ZrC x .…”

Section: Resultsmentioning

confidence: 58%

Carbon vacancy ordering in zirconium carbide powder

et al. 2019

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Ordered carbon vacancies were detected in zirconium carbide (ZrCx) powders that were synthesized by direct reaction. Zirconium hydride (ZrH2) and carbon black were used as starting powders with the molar ratio of ZrH2:C = 1:0.6. Powders were reacted at 1300°C or 2000°C. The major phase detected by x‐ray diffraction (XRD) was ZrCx. No excess carbon was observed by transmission electron microscopy (TEM) in powders synthesized at either temperature. Ordering of the carbon vacancies was identified by neutron powder diffraction (NPD) and further supported by selected area electron diffraction (SAED). The vacancies in carbon‐deficient ZrCx exhibited diamond cubic symmetry with a supercell that consisted of eight (2 × 2 × 2) ZrCx unit cells with the rock‐salt structure. Rietveld refinement of the neutron diffraction patterns revealed that the synthesis temperature did not have a significant effect on the degree of vacancy ordering in ZrCx powders. Direct synthesis of ZrC0.6 resulted in the partial ordering of carbon vacancies without the need for extended isothermal annealing as reported in previous experimental studies.

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Section: Resultsmentioning

confidence: 58%

Carbon vacancy ordering in zirconium carbide powder

et al. 2019

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“…[14] The other reason is that oxygen can enter into the crystal lattice of ZrC to form Zr(C, O) solid solution causing the decrease of lattice parameter of ZrC. [15] So the reaction product of ZrC might be nonstoichiometric ZrC x with oxygen solution. The oxygen comes from the oxygen contamination on the surfaces of ZrB 2 and Zr.…”

Section: Resultsmentioning

confidence: 99%

Hot‐Pressed ZrB₂ Ceramics With Composite Additives of Zr and B₄C

et al. 2010

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This work pointed out a new approach to get dense ZrB2 ceramics by forming refractory second phases through adding reactive composite additives. With the combination of Zr and B4C additives at a 3:1 molar ratio, the densification, microstructure, and mechanical properties of hot‐pressed ZrB2 ceramics were investigated. The Zr reacted with B4C at relatively low temperature of 1400 °C to form the secondary ultra‐high‐temperature ZrB2 and ZrC phases with high sinterability, which would be beneficial to improve the densification and maintain the high‐temperature properties of ZrB2 ceramics. For comparison, the separate effects of B4C or Zr additive on densification and microstructures of ZrB2 ceramics were also investigated.

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“…Due to the lack of experimental thermochemical data pertaining to the liquid phase on the B–O system, the interaction parameters were estimated based on the experimental phase diagram data (i.e., invariant temperature, congruent melting point, and the liquidus temperatures). Within the temperature range of interest (1500°C–1900°C), the only ternary solid solution (with significant solubility extending into the ternary composition space) is the zirconium oxycarbide, Zr(C 1‐ x O x ) on the Zr–O–C ternary system and the interaction parameters were estimated based on the experimental phase diagram data available in literature . A complete thermodynamic modeling of the Zr–C–O–B quaternary system obtained within the CALPHAD framework will be published elsewhere.…”

Section: Methodsmentioning

confidence: 99%

Processing Low‐Oxide ZrB₂ Ceramics with High Strength Using Boron Carbide and Spark Plasma Sintering

et al. 2016

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A phase diagram-assisted powder processing approach is shown to produce low-oxygen (0.06 wt%O) ZrB 2 ceramics using minimal B 4 C additions (0.25 wt%) and spark plasma sintering. Scanning electron microscopy and scanning transmission electron microscopy with elemental spectroscopy are used to identify "trash collector" oxides. These "trash collector" oxides are composed of manufacturer metal powder impurities that form discreet oxide particles due to the absence of standard Zr-B oxides found in high oxygen samples. A preliminary Zr-B-C-O quaternary thermodynamic database developed as a part of this work was used to calculate the ZrO 2 -B 4 C pseudobinary phase diagram and ZrB 2 -ZrO 2 -B 4 C pseudoternary phase diagrams. We use the calculated equilibrium phase diagrams to characterize the oxide impurities and show the direct reaction path that allows for the formation of ZrB 2 with an oxygen content of 0.06 wt%, fine grains (3.3 lm) and superior mechanical properties (flexural strength of 660 MPa).

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Solubility of Oxygen in ZrC

Cited by 55 publications

References 0 publications

Carbon vacancy ordering in zirconium carbide powder

Carbon vacancy ordering in zirconium carbide powder

Hot‐Pressed ZrB₂ Ceramics With Composite Additives of Zr and B₄C

Processing Low‐Oxide ZrB₂ Ceramics with High Strength Using Boron Carbide and Spark Plasma Sintering

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Solubility of Oxygen in ZrC

Cited by 55 publications

References 0 publications

Carbon vacancy ordering in zirconium carbide powder

Carbon vacancy ordering in zirconium carbide powder

Hot‐Pressed ZrB2 Ceramics With Composite Additives of Zr and B4C

Processing Low‐Oxide ZrB2 Ceramics with High Strength Using Boron Carbide and Spark Plasma Sintering

Contact Info

Product

Resources

About

Hot‐Pressed ZrB₂ Ceramics With Composite Additives of Zr and B₄C

Processing Low‐Oxide ZrB₂ Ceramics with High Strength Using Boron Carbide and Spark Plasma Sintering