Matches in SemOpenAlex for { <https://semopenalex.org/work/W3156211837> ?p ?o ?g. }
Showing items 1 to 73 of
73
with 100 items per page.
- W3156211837 abstract "In order to gain further understanding about the onset mechanisms of flash sintering, the electrical properties of cubic calcia-stabilised zirconia, CSZ (CaxZr1-xO2-x: 0.12≤x≤0.18) and Mg-doped alumina (0.05wt%MgO-Al2O3 and 0.5wt%(MgO/SiO2)- Al2O3) ceramics were investigated using impedance spectroscopy as a function of temperature, oxygen partial pressure and applied dc bias. Equivalent circuit analysis was carried out to identify the electrical microstructure of the materials. As part of this process, the relative importance of individual elements to the overall impedance response was highlighted by a new approach by the deconvolution of the impedance spectra.The bulk, grain boundary and electrode contact impedances of CSZ ceramics were characterised over the temperature range 200-930°C. The most appropriate equivalent circuit to characterise the bulk response required inclusion of a dielectric component, represented by a series RC element, in parallel with the oxide ion conductivity represented by a parallel combination of a resistance, capacitance and constant phase element. The dielectric component may be attributed to defect complexes involving CaZr’’–VO •• pairswhereas long range conduction involves single oxygen vacancies. The activation energy for the dielectric component increased with increasing x. This was attributed to an increase in the number of pairs or to their coalescence into larger aggregates, causing greater difficulty in reorientation of the dipoles. The sample-electrode interface response was deconvoluted into two components, the charge transfer (Rct) and diffusion resistance (Rdiff), where Rct << Rdiff.Impedance analysis of CSZ ceramics under different atmospheres showed that the limits of the electrolytic domain vary with temperature and composition. Around 400°C, the bulk conductivity of all compositions remained independent of pO2 and the samples were pure oxide ion conductors, but near 930°C, x=0.12 showed introduction of n-type conduction and x=0.18 showed p-type whereas the intermediate composition x=0.15 did not show any pO2 dependence.The total resistance of CSZ ceramics decreased with application of a dc bias. This was attributed to the introduction of p-type conductivity. Electron holes might be located on under-bonded oxygen ions, associated either with the Ca dopant ions, or those near the ceramic surface, resulting in a mixed ionic-electronic conduction pathway.A flash sintering set-up was built. Flash sintering experiments on CSZ x=0.15 showed increased conductivity and emission of light, but no sample densification. It was concluded that the sintering process can be separated from the emission of light and increase in conductivity and therefore, that the origin of these phenomena, ie flash and sintering, might be different.Impedance measurements on two Mg-doped alumina ceramics, over the temperature range 400-910°C, showed a combination of low-level oxide ion conductivity and p-type electronic conductivity, depending on temperature, oxygen partial pressure and dopant content. The oxide ion conductivity was attributed to oxygen vacancies, introduced as charge compensation for the Mg dopant. The p-type conductivity was attributed to hole location on under-bonded oxide ions and was identified as the dominant conduction pathway for measurements in air at high temperatures. The sample resistance increased on application of a dc bias. This was attributed to electron-hole recombination and the loss of p-type conductivity associatedwith oxygen loss." @default.
- W3156211837 created "2021-04-26" @default.
- W3156211837 creator A5021089372 @default.
- W3156211837 date "2020-09-01" @default.
- W3156211837 modified "2023-09-23" @default.
- W3156211837 title "Synthesis and Electrical Characterization of Calcia-stabilised Zirconia and Mg-doped Alumina" @default.
- W3156211837 hasPublicationYear "2020" @default.
- W3156211837 type Work @default.
- W3156211837 sameAs 3156211837 @default.
- W3156211837 citedByCount "0" @default.
- W3156211837 crossrefType "dissertation" @default.
- W3156211837 hasAuthorship W3156211837A5021089372 @default.
- W3156211837 hasConcept C113196181 @default.
- W3156211837 hasConcept C123609680 @default.
- W3156211837 hasConcept C124579511 @default.
- W3156211837 hasConcept C133386390 @default.
- W3156211837 hasConcept C134132462 @default.
- W3156211837 hasConcept C147789679 @default.
- W3156211837 hasConcept C159985019 @default.
- W3156211837 hasConcept C17525397 @default.
- W3156211837 hasConcept C185592680 @default.
- W3156211837 hasConcept C192562407 @default.
- W3156211837 hasConcept C43617362 @default.
- W3156211837 hasConcept C47908070 @default.
- W3156211837 hasConcept C49040817 @default.
- W3156211837 hasConcept C52859227 @default.
- W3156211837 hasConcept C57863236 @default.
- W3156211837 hasConcept C7040849 @default.
- W3156211837 hasConcept C87976508 @default.
- W3156211837 hasConceptScore W3156211837C113196181 @default.
- W3156211837 hasConceptScore W3156211837C123609680 @default.
- W3156211837 hasConceptScore W3156211837C124579511 @default.
- W3156211837 hasConceptScore W3156211837C133386390 @default.
- W3156211837 hasConceptScore W3156211837C134132462 @default.
- W3156211837 hasConceptScore W3156211837C147789679 @default.
- W3156211837 hasConceptScore W3156211837C159985019 @default.
- W3156211837 hasConceptScore W3156211837C17525397 @default.
- W3156211837 hasConceptScore W3156211837C185592680 @default.
- W3156211837 hasConceptScore W3156211837C192562407 @default.
- W3156211837 hasConceptScore W3156211837C43617362 @default.
- W3156211837 hasConceptScore W3156211837C47908070 @default.
- W3156211837 hasConceptScore W3156211837C49040817 @default.
- W3156211837 hasConceptScore W3156211837C52859227 @default.
- W3156211837 hasConceptScore W3156211837C57863236 @default.
- W3156211837 hasConceptScore W3156211837C7040849 @default.
- W3156211837 hasConceptScore W3156211837C87976508 @default.
- W3156211837 hasLocation W31562118371 @default.
- W3156211837 hasOpenAccess W3156211837 @default.
- W3156211837 hasPrimaryLocation W31562118371 @default.
- W3156211837 hasRelatedWork W1569702809 @default.
- W3156211837 hasRelatedWork W1844963743 @default.
- W3156211837 hasRelatedWork W1993222057 @default.
- W3156211837 hasRelatedWork W2003111882 @default.
- W3156211837 hasRelatedWork W2007153982 @default.
- W3156211837 hasRelatedWork W2024006597 @default.
- W3156211837 hasRelatedWork W2035042297 @default.
- W3156211837 hasRelatedWork W2051106329 @default.
- W3156211837 hasRelatedWork W2084066775 @default.
- W3156211837 hasRelatedWork W2093857410 @default.
- W3156211837 hasRelatedWork W2326773715 @default.
- W3156211837 hasRelatedWork W2333388771 @default.
- W3156211837 hasRelatedWork W2620470278 @default.
- W3156211837 hasRelatedWork W2781762567 @default.
- W3156211837 hasRelatedWork W2946305207 @default.
- W3156211837 hasRelatedWork W3116814824 @default.
- W3156211837 hasRelatedWork W3163487020 @default.
- W3156211837 hasRelatedWork W3213115025 @default.
- W3156211837 hasRelatedWork W847083892 @default.
- W3156211837 hasRelatedWork W2787709912 @default.
- W3156211837 isParatext "false" @default.
- W3156211837 isRetracted "false" @default.
- W3156211837 magId "3156211837" @default.
- W3156211837 workType "dissertation" @default.