Pressureless sintering of ZrC with variable stoichiometry

Schönfeld, Katrin; Martin, Hans-Peter; Michaelis, Alexander

doi:10.1007/s40145-017-0229-1

Cited by 31 publications

(16 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…This result was also consistent with other studies whose TEM analysis revealed amorphous carbon on the ~100 nanometre scale 24 . The extended network of intra and intergranular depressions as seen in the SEM images has also been observed in previous studies 12,15,19,24 . These features were seen to be comprised of sp 2 pristine, 'partially destroyed' graphite and amorphous carbon structures can be seen from the Raman spectra of samples produced in this study.…”

Section: Discussionsupporting

confidence: 87%

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

Rana

Solvas

Lee

et al. 2020

Sci Rep

View full text Add to dashboard Cite

An investigation of the longrange and local structure of substoichiometric zirconium carbide sintered at different temperatures Dhan-sham B. K. Rana 1* , Eugenio Zapatas Solvas 2 , William e. Lee 2 & ian farnan 1 Zrc 1−x (sub-stoichiometric zirconium carbide), a group IV transition metal carbide, is being considered for various high temperature applications. Departure from stoichiometry changes the thermo-physical response of the material. Reported thermo-physical properties exhibit, in some cases, a degree of scatter with one likely contributor to this being the uncertainty in the C/Zr ratio of the samples produced. Conventional, methods for assigning C/Zr to samples are determined either by nominal stochiometric ratios or combustion carbon analysis. In this study, a range of stoichiometries of hotpressed ZrC 1−x were examined by SEM, XRD, Raman spectroscopy and static 13 C NMR spectroscopy and used as a basis to correct the C/Zr. Graphite, amorphous, and ZrC 1−x carbon signatures are observed in the 13 C NMR spectra of samples and are determined to vary in intensity with sintering temperature and stoichiometry. In this study a method is outlined to quantify the stoichiometry of ZrC 1−x and free carbon phases, providing an improvement over the sole use and reliance of widely adopted bulk carbon combustion analysis. We report significantly lower C/Zr values determined by 13 C NMR analysis compared with carbon analyser and nominal methods. Furthermore, the location of carbon disassociated from the Zrc 1−x structure is analysed using SEM and Raman spectroscopy. ZrC 1−x (sub-stoichiometric zirconium carbide), is under consideration for its use in generation IV nuclear fuel coatings due to its favourable mechanical, thermal, neutronic, and fission product retention properties 1-4. This combination of characteristics is derived from the combination of its metallic electronic properties and its ceramic properties 5. ZrC crystallises in the rocksalt structure with carbon atoms located in the octahedral interstitial sites. When carbon is removed from the ZrC structure, significant changes are seen in the physical and thermal properties. Scatter in reported data exists in the variation of the physical properties with the atomic C/Zr ratio. The scatter in the data potentially arises due to the combination of two factors: inaccurate composition measurements (C/Zr ratio) resulting in misreferenced physical properties; and the contribution of interstitial impurities such as oxygen and nitrogen leading to a range values for several themo-physical properties. Non-monotonic trends in material properties have been observed for physical properties, such as the lattice parameter. Assuming the sub-stochiometric material is comprised exclusively of ZrC and no contaminant species the configuration ordering of carbon atoms as the concentration of vacancies increases may be a contributing factor to the occurrence of these non-monotonic trends. As understanding of how these vacancies interact and how this affects material properties is c...

show abstract

Section: Discussionsupporting

confidence: 87%

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

Rana

Solvas

Lee

et al. 2020

Sci Rep

View full text Add to dashboard Cite

show abstract

“…2 Similarly, variable carbon stoichiometry is exhibited by other TMCs, such as TiC x , [3][4][5] HfC x , 6,7 VC x , 8 NbC x , 3,9 TaC x , 10,11 and WC x . 12 Carbon stoichiometry affects the sinterability, [13][14][15] mechanical properties, 16,17 electrical properties, 18 and radiation resistance 19 of ZrC x ceramics. Short-and long-range ordering of carbon vacancies in nonstoichiometric carbides have both been studied theoretically.…”

Section: Introductionmentioning

confidence: 99%

Carbon vacancy ordering in zirconium carbide powder

et al. 2019

View full text Add to dashboard Cite

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.

show abstract

“…Five measurements were taken for each sample and average of hardness and density results belonging to the composites are presented in Table I. Since ZrC has a theoretical density of 6.73 [7], the density of the composite increases with the addition of ZrC. However, there was a slight decrease in density with the increase of the reinforcement amount.…”

Section: Resultsmentioning

confidence: 99%

Investigation of Microstructural and Mechanical Properties of Zirconium Carbide Reinforced Aluminum Matrix Nanocomposites

Çuğ

Zengin

2019

Acta Phys. Pol. A

View full text Add to dashboard Cite

This study aims to investigate the effect of zirconium carbide (ZrC) nanoparticles on mechanical performances of pure aluminum. Composites Al-0.5ZrC, Al-1ZrC, Al-2ZrC were fabricated by powder metallurgy. Hardness test was performed for all specimens. Compression test was conducted at room temperature. Results clearly show that homogenously distribution of nanoparticles was achieved up to 1 wt% reinforcement addition according to the scanning electron microscope results. The hardness of pure aluminum was increased significantly. Compression strength was also improved considerably with the addition of nano-reinforcements. Al-1ZrC composite showed best performance among the samples.

show abstract

Pressureless sintering of ZrC with variable stoichiometry

Cited by 31 publications

References 28 publications

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

An investigation of the long-range and local structure of sub-stoichiometric zirconium carbide sintered at different temperatures

Carbon vacancy ordering in zirconium carbide powder

Investigation of Microstructural and Mechanical Properties of Zirconium Carbide Reinforced Aluminum Matrix Nanocomposites

Contact Info

Product

Resources

About