Hydrotermální koroze keramiky na bázi ZrO2

Hydrothermal corrosion of zirconia ceramics

conference paper

en

The aim of the present work is to describe the course of hydrothermal transformation of the zirconia material in the temperature range from 140 to 260C and to establish the change in its mechanical properties after hydrothermal transformation. It was found: At temperatures from 140C to 260C some 7 to62 wt.% of tetragonal phase transformed on specimen surface into monoclinic phase. The transformation of tetragonal zirconia at temperatures of 180 and higher was the most intensive. At temperatures of 180C and higher a layer of transformed material was formed on the surface of material. Its thickness increased with temperature and reached as much as 170 mm Temperatures of 180C and more are critical from the viewpoint of changes in the microstructure and mechanical properties for this material.

Byl studován vliv hydrotermálních podmínek na fázovou stabilitu, mikrostrukturu a mechanické vlastnosti tetragonální ZrO2 keramiky stabilizované 3 mol% Y2O3. Při teplotách 140-260C došlo k transformaci tetragonální fáze na monoklinický ZrO2 doprovázené úbytkem obsahu ytria v materiálu. Míra transformace rostla s rostoucí teplotou a dobou působení. Změna mikrostruktury a mechanických vlastností byla zaznamenána při teplotách 180C a vyšších. S rostoucí teplotou tloušťka porézní transformované vrstvy rostla a při 260C dosáhla tloušťky 170 ?m. Změna mechanických vlastností (tvrdosti a lomové houževnatosti) odpovídala strukturním změnám v materiálu způsobených hydrotermálním působením. Teploty 180C a vyšší byly pro mechanické a strukturní vlastnosti materiálu kritické.

The aim of the present work is to describe the course of hydrothermal transformation of the zirconia material in the temperature range from 140 to 260C and to establish the change in its mechanical properties after hydrothermal transformation. It was found: At temperatures from 140C to 260C some 7 to62 wt.% of tetragonal phase transformed on specimen surface into monoclinic phase. The transformation of tetragonal zirconia at temperatures of 180 and higher was the most intensive. At temperatures of 180C and higher a layer of transformed material was formed on the surface of material. Its thickness increased with temperature and reached as much as 170 mm Temperatures of 180C and more are critical from the viewpoint of changes in the microstructure and mechanical properties for this material.

zirconia, hydrothermal ageing, phase transformation, mechanical properties

2003

01.01.2003

Faculty of Technology, University of Novi Sad

Novi Sad

86-80995-46-0

School of ceramics: V Students Meeting, Book of Extend Abstracts

2003

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