FRINK Linked Data Fragments server

Matches in SemOpenAlex for { <https://semopenalex.org/work/W428142720> ?p ?o ?g. }

• W428142720 abstract "The term Nanoceramics is well known in the ceramic field for at least two decades. In this project a detailed study was performed on the synthesis of α-alumina nanopowders. High solids content nanoalumina suspensions were prepared and used to form green bodies using both wet and dry forming routes. The green bodies were then sintered using both conventional single and two-step sintering approaches.Synthesis: Two different synthesis methods, viz. precipitation and hydrothermal treatment, were used to synthesize fine α-alumina powders from aluminium chloride, ammonia solution and TEAH (Tetraethyl ammonium hydroxide). XRD, TEM and FEG-SEM were used to characterise the powders produced. The presence of commercial α-alumina powder as seed particles did not affect the transformation to α-alumina phase during the hydrothermal treatment at 220˚C in either basic or acidic environments. The results obtained from the precipitation route showed that the combined effect of adding α-alumina seeds and surfactants to the precursor solution could lower the transformation temperature of α-alumina from about 1200˚C for unseeded samples to 800˚C, as well as reducing the level of agglomeration in the alumina powders. The difference in transformation temperature mainly resulted from the nucleation process by the α-alumina seeds, which enhanced the θ → α transformation kinetics. The lower level of agglomeration present in the final powders could be due to the surface modifying role of the surfactants preventing the particles from growing together during the synthesis process. By introducing a further high-temperature step for a very short duration (1 minute) to the low-temperature heat treatment route (800˚C/12 h), the unseeded sample with added surfactant transformed into pure α-alumina phase. The newly-added step was shown to be an in-situ seeding step, followed by a conventional nucleation and growth process. The best final powder was compared with a commercial α-alumina nanopowder.Processing of alumina ceramics: The effect of low-molecular weight ammonium dispersants including Dispex-A40, Darvan-C and Dolapix-CE64, on high solids content nanoalumina suspensions was investigated. The nanosuspension prepared using the most suitable dispersant, Dolapix-CE64, was slip cast into ~53% dense, very homogeneous green bodies. This nanosuspension was also spray freeze dried into crushable granules using Freon as a foaming agent. Green compacts with density of ~53.5% were then formed by dry pressing the 2 vol% Freon-added spray freeze dried granules at 40 MPa. Both slip cast and die pressed green bodies were sintered using conventional single-step and two-step routes followed by characterising the density and grain size measurement of final dense compacts. The results have been compared with that of a submicron alumina ceramic prepared using a commercial α-alumina suspension. Highly dense alumina with an average grain size of ~0.6 μm was fabricated by means of spark plasma sintering at 1200˚C. The application of 500 MPa allowed achieving almost fully dense alumina at temperature as low as 1200˚C for 30 minutes with no significant grain growth." @default.
• W428142720 created "2016-06-24" @default.
• W428142720 creator A5067508719 @default.
• W428142720 date "2013-01-01" @default.
• W428142720 modified "2023-09-26" @default.
• W428142720 title "Synthesis and processing of nanostructured alumina ceramics" @default.
• W428142720 hasPublicationYear "2013" @default.
• W428142720 type Work @default.
• W428142720 sameAs 428142720 @default.
• W428142720 citedByCount "0" @default.
• W428142720 crossrefType "dissertation" @default.
• W428142720 hasAuthorship W428142720A5067508719 @default.
• W428142720 hasConcept C107054158 @default.
• W428142720 hasConcept C121332964 @default.
• W428142720 hasConcept C127413603 @default.
• W428142720 hasConcept C131850264 @default.
• W428142720 hasConcept C134132462 @default.
• W428142720 hasConcept C147424627 @default.
• W428142720 hasConcept C153294291 @default.
• W428142720 hasConcept C156622251 @default.
• W428142720 hasConcept C178790620 @default.
• W428142720 hasConcept C185592680 @default.
• W428142720 hasConcept C191897082 @default.
• W428142720 hasConcept C192562407 @default.
• W428142720 hasConcept C2775896084 @default.
• W428142720 hasConcept C2777581544 @default.
• W428142720 hasConcept C2777879272 @default.
• W428142720 hasConcept C2779660836 @default.
• W428142720 hasConcept C42360764 @default.
• W428142720 hasConcept C513153333 @default.
• W428142720 hasConcept C61048295 @default.
• W428142720 hasConceptScore W428142720C107054158 @default.
• W428142720 hasConceptScore W428142720C121332964 @default.
• W428142720 hasConceptScore W428142720C127413603 @default.
• W428142720 hasConceptScore W428142720C131850264 @default.
• W428142720 hasConceptScore W428142720C134132462 @default.
• W428142720 hasConceptScore W428142720C147424627 @default.
• W428142720 hasConceptScore W428142720C153294291 @default.
• W428142720 hasConceptScore W428142720C156622251 @default.
• W428142720 hasConceptScore W428142720C178790620 @default.
• W428142720 hasConceptScore W428142720C185592680 @default.
• W428142720 hasConceptScore W428142720C191897082 @default.
• W428142720 hasConceptScore W428142720C192562407 @default.
• W428142720 hasConceptScore W428142720C2775896084 @default.
• W428142720 hasConceptScore W428142720C2777581544 @default.
• W428142720 hasConceptScore W428142720C2777879272 @default.
• W428142720 hasConceptScore W428142720C2779660836 @default.
• W428142720 hasConceptScore W428142720C42360764 @default.
• W428142720 hasConceptScore W428142720C513153333 @default.
• W428142720 hasConceptScore W428142720C61048295 @default.
• W428142720 hasLocation W4281427201 @default.
• W428142720 hasOpenAccess W428142720 @default.
• W428142720 hasPrimaryLocation W4281427201 @default.
• W428142720 hasRelatedWork W1985289533 @default.
• W428142720 hasRelatedWork W1992146927 @default.
• W428142720 hasRelatedWork W2000889473 @default.
• W428142720 hasRelatedWork W2015019928 @default.
• W428142720 hasRelatedWork W2019520103 @default.
• W428142720 hasRelatedWork W2044860979 @default.
• W428142720 hasRelatedWork W2047872577 @default.
• W428142720 hasRelatedWork W2070486803 @default.
• W428142720 hasRelatedWork W2078496379 @default.
• W428142720 hasRelatedWork W2133755511 @default.
• W428142720 hasRelatedWork W2242600057 @default.
• W428142720 hasRelatedWork W2317131139 @default.
• W428142720 hasRelatedWork W2328025038 @default.
• W428142720 hasRelatedWork W2806444555 @default.
• W428142720 hasRelatedWork W3043806694 @default.
• W428142720 hasRelatedWork W3146963642 @default.
• W428142720 hasRelatedWork W2181751291 @default.
• W428142720 hasRelatedWork W2287913991 @default.
• W428142720 hasRelatedWork W2468061136 @default.
• W428142720 hasRelatedWork W2859707391 @default.
• W428142720 isParatext "false" @default.
• W428142720 isRetracted "false" @default.
• W428142720 magId "428142720" @default.
• W428142720 workType "dissertation" @default.