MICROSTRUCTURE AND GRAIN SIZE DISTRIBUTIONS IN MAGNESIA-ALUMINA SPINEL CERAMICS PREPARED BY SPARK PLASMA SINTERING

Kód výsledku v IS VaVaI

<a href="https://www.isvavai.cz/riv?ss=detail&h=RIV%2F60461373%3A22310%2F18%3A43915091" target="_blank" >RIV/60461373:22310/18:43915091 - isvavai.cz</a>

Výsledek na webu

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DOI - Digital Object Identifier

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Jazyk výsledku

angličtina

Název v původním jazyce

MICROSTRUCTURE AND GRAIN SIZE DISTRIBUTIONS IN MAGNESIA-ALUMINA SPINEL CERAMICS PREPARED BY SPARK PLASMA SINTERING

Popis výsledku v původním jazyce

Magnesia-alumina spinel (MAS) is one of the favorite materials for preparing transparent ceramics for impact-resistant optical windows. Therefore both optical and mechanical properties are important for these ceramics. Apart from highest density and the absence of pores, which can both be achieved by spark plasma sintering (SPS), the grain size is the main parameter that can be optimized. On the other hand, from the theoretical point of view, MAS prepared by SPS is an ideal system to study grain growth unconstrained by pores or second-phase inclusions. This contribution presents a systematic approach for the microstructural characterization of MAS ceramics prepared by SPS. Based on SEM images, obtained from thermally etched planar sections, the mean chord length and Jeffries size and related microstructural descriptors (grain boundary density, mean curvature integral density, linear and planar grain size numbers) are calculated, and grain size distributions are obtained from grain section size distributions, using the Saltykov, Cruz-Orive and Woodhead transformations for the tentative correction of the random section problem. It is found that all grain size distributions are very close to Rayleigh distributions and that the “average” grain size increases to 0.8–1.2 μm when the SPS process is performed at 1500 °C with 30 min dwell, compared to 0.6–0.8 μm for samples prepared by SPS at lower temperature (1400 °C) or with shorter dwell time (0 min). Concomitantly with the grain growth the number density decreases, from approximately 1.4–2.8 μm–3 to 0.6–0.8 μm–3.

Název v anglickém jazyce

MICROSTRUCTURE AND GRAIN SIZE DISTRIBUTIONS IN MAGNESIA-ALUMINA SPINEL CERAMICS PREPARED BY SPARK PLASMA SINTERING

Popis výsledku anglicky

Magnesia-alumina spinel (MAS) is one of the favorite materials for preparing transparent ceramics for impact-resistant optical windows. Therefore both optical and mechanical properties are important for these ceramics. Apart from highest density and the absence of pores, which can both be achieved by spark plasma sintering (SPS), the grain size is the main parameter that can be optimized. On the other hand, from the theoretical point of view, MAS prepared by SPS is an ideal system to study grain growth unconstrained by pores or second-phase inclusions. This contribution presents a systematic approach for the microstructural characterization of MAS ceramics prepared by SPS. Based on SEM images, obtained from thermally etched planar sections, the mean chord length and Jeffries size and related microstructural descriptors (grain boundary density, mean curvature integral density, linear and planar grain size numbers) are calculated, and grain size distributions are obtained from grain section size distributions, using the Saltykov, Cruz-Orive and Woodhead transformations for the tentative correction of the random section problem. It is found that all grain size distributions are very close to Rayleigh distributions and that the “average” grain size increases to 0.8–1.2 μm when the SPS process is performed at 1500 °C with 30 min dwell, compared to 0.6–0.8 μm for samples prepared by SPS at lower temperature (1400 °C) or with shorter dwell time (0 min). Concomitantly with the grain growth the number density decreases, from approximately 1.4–2.8 μm–3 to 0.6–0.8 μm–3.

Druh

D - Stať ve sborníku

CEP obor

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OECD FORD obor

20504 - Ceramics

Projekt

<a href="/cs/project/GA15-18513S" target="_blank" >GA15-18513S: Příprava a charakterizace oxidové a silikátové keramiky s řízenou mikrostrukturou a modelování souvislostí mezi mikrostrukturou a vlastnostmi</a><br>

Návaznosti

P - Projekt vyzkumu a vyvoje financovany z verejnych zdroju (s odkazem do CEP)

Rok uplatnění

2018

Kód důvěrnosti údajů

S - Úplné a pravdivé údaje o projektu nepodléhají ochraně podle zvláštních právních předpisů

Název statě ve sborníku

Proceedings of the 12th Pacific Rim Conference on Ceramic and Glass Technology

ISBN

978-1-119-49421-8

ISSN

1042-1122

e-ISSN

neuvedeno

Počet stran výsledku

12

Strana od-do

41-52

Název nakladatele

American Ceramic Society (ACerS)

Místo vydání

Westerville, Ohio

Místo konání akce

Waikoloa

Datum konání akce

21. 5. 2017

Typ akce podle státní příslušnosti

WRD - Celosvětová akce

Kód UT WoS článku

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