Investigation of thermal oxidation resistance of nanopowders of refractory carbides and borides

Руднева, В. В.; Галевский, Г. В.

doi:10.3103/s1067821207020137

Cited by 11 publications

(3 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Among these materials, titanium carbide could be a good candidate because it is spectrally selective and it has good mechanical properties. However, it also has a low resistance to oxidation [25][26][27][28][29][30][31][32]. Previous studies showed that the combination of SiC and TiC in a nanocomposite material could be a good solution to obtain a material that is spectrally selective as well as resistant to oxidation [33].…”

Section: Introductionmentioning

confidence: 99%

SiC-TiC nanocomposite for bulk solar absorbers applications: Effect of density and surface roughness on the optical properties

Aréna

Coulibaly

Soum‐Glaude

et al. 2019

Solar Energy Materials and Solar Cells

View full text Add to dashboard Cite

In this study, the potential of SiC-TiC nano-composites as solar absorbers has been studied. For solar thermal applications, materials with high solar absorptance and low emittance are ideally sought for (spectral selectivity). A semi-molecular sol-gel synthesis route leading to nanometric homogenous composites was described. The resulting SiC-TiC nanocomposite powder was sintered at different temperatures to produce samples with various relative densities (from 57 to 96 %). The samples morphology and composition were characterised by several techniques including Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray Spectroscopy (EDX), X-Ray Diffraction (XRD), carbon and oxygen elemental analyses. The link between the surface roughness and the relative density was precised and the effects on the optical properties (0.25 to 25 µm wavelength range) were studied. Comparisons were made with pure SiC and pure TiC samples with various relative densities.Overall, the sample emittance was found to strongly decrease with the increase in the relative density, leading to a great increase in the spectral selectivity, despite a little decrease in the solar absorptance. The TiC-SiC composite has an intermediate reflectance compared to the pure SiC and the pure TiC samples. With an absorptance of 0.76, an emittance of 0.44 and a selectivity of 1.74, the denser SiC-TiC could be a good candidate for bulk solar applications.

show abstract

Section: Introductionmentioning

confidence: 99%

SiC-TiC nanocomposite for bulk solar absorbers applications: Effect of density and surface roughness on the optical properties

Aréna

Coulibaly

Soum‐Glaude

et al. 2019

Solar Energy Materials and Solar Cells

View full text Add to dashboard Cite

show abstract

“…Coulibaly et al compared the optical properties of several carbides and demonstrated that titanium carbide (TiC) is one of the best compound in this group, due to its particularly low emittance [29]. However, the major limitation of this material is its low resistance to oxidation [30][31][32][33][34][35][36][37].…”

Section: Introductionmentioning

confidence: 99%

Effect of TiC incorporation on the optical properties and oxidation resistance of SiC ceramics

Aréna

Coulibaly

Soum‐Glaude

et al. 2020

Solar Energy Materials and Solar Cells

View full text Add to dashboard Cite

In concentrating solar power (CSP) technologies, the absorber material should be spectrally selective under severe operating conditions, i.e. ~1000°C under air atmosphere. SiC-TiC nanocomposites could be good candidates for this application due to their spectral selectivity at room temperature, but their behavior under CSP operating conditions is unknown. Therefore, the spectral selectivity and oxidation resistance of TiC-SiC composites were studied up to 500 °C, under air, for various compositions. During heating, the emittance increased with the temperature. After heating, the TiC grains at the surface were oxidized into TiO2, while SiC grains showed good behavior. However, despite little oxidation, the spectral selectivity of the nanocomposites remained interesting after heating. Specific oxidation tests up to 9 days at 1000°C under air showed an increase of the oxidation resistance with the amount of SiC. This result is the consequence of the formation of a protective layer of SiO2 preventing the oxidation of the TiC grains. The composition 30 at% TiC-70 at% SiC seems to be a good compromise between low oxidation and good selectivity.

show abstract

“…Transition metal borides have been considered as advanced structural materials because of their high melting point, 1,2 hardness, 3-7 wear/corrosion/oxidation resistance 8, 9 and excellent thermal 10, 11 and electrical properties. 12 It finds applications as cathode materials, 13,14 high temperature materials [15][16][17] and in electronic devices. [18][19][20][21] Five different types of niobium borides with variable Nb : B molar ratios are known (Nb 3 B 2 , NbB, Nb 5 B 6 , Nb 3 B 4 and NbB 2 ).…”

Section: Introductionmentioning

confidence: 99%

Novel borothermal process for the synthesis of nanocrystalline oxides and borides of niobium

et al. 2011

View full text Add to dashboard Cite

A new process has been developed for the synthesis of nanocrystalline niobium oxide and niobium diboride using an amorphous niobium precursor obtained via the solvothermal route. On varying the ratio of niobium precursor to boron and the reaction conditions, pure phases of nanostructured niobium oxides (Nb(2)O(5), NbO(2)), niobium diboride (NbB(2)) and core-shell nanostructures of NbB(2)@Nb(2)O(5) could be obtained at normal pressure and low temperature of 1300 °C compared to a temperature of 1650 °C normally used. The above borothermal process involves the in situ generation of B(2)O(2) to yield either oxide or diboride. The niobium oxides and borides have been characterized in detail by XRD, HRTEM and EDX studies. The core-shell structure has been investigated by XPS depth profiling, EFTEM and EELS (especially to characterize the presence of boron and the shell thickness). The niobium diboride nanorods (with high aspect ratio) show a superconducting transition with the T(c) of 6.4 K. In the core-shell of NbB(2)@Nb(2)O(5), the superconductivity of NbB(2) is masked by the niobium oxide shell and hence no superconductivity was observed. The above methodology has the benefits of realizing both oxides and borides of niobium in nanocrystalline form, in high purity and at much lower temperatures.

show abstract

Investigation of thermal oxidation resistance of nanopowders of refractory carbides and borides

Cited by 11 publications

References 1 publication

SiC-TiC nanocomposite for bulk solar absorbers applications: Effect of density and surface roughness on the optical properties

SiC-TiC nanocomposite for bulk solar absorbers applications: Effect of density and surface roughness on the optical properties

Effect of TiC incorporation on the optical properties and oxidation resistance of SiC ceramics

Novel borothermal process for the synthesis of nanocrystalline oxides and borides of niobium

Contact Info

Product

Resources

About