Izostatické lisování za studena a slinování Al2O3 a ZrO2 nanokeramiky

Cold isostatic pressing and sintering of alumina and zirconia nanoceramics

conference paper

en

The influence of particle size and compacting pressure on the microstructure and sinterability of ceramic green bodies were studied. Alumina and zirconia powders with particle size smaller than 35 nm were used and their behaviour was compared with submicrometre sized powders. The green bodies were prepared by cold isostatic pressing at 300, 700 and 1000 MPa. The open porosity of pressed samples was evaluated by mercury intrusion. Specimens were sintered in high temperature dilatometer. The microstructure was examined using electron microscopy. In the case of zirconia ceramics the sintering temperature decreased with decreasing particle size and with increasing compacting pressure. Zirconia nanoceramics exhibited final microstructure with grain size below 80 nm and density exceeding 99 % of theoretical density after sintering at 1100°C. Alumina samples made of nanopowders showed poor sinterability probably due to high level of powder agglomeration.

Byl studován vliv velikosti částic a lisovacího tlaku na mikrostrukturu a slinování keramických polotovarů. Byly použity Al2O3 a ZrO2 prášky s velikostí částic menších než 35nm a jejich chování bylo srovnáno se submikrometrickými prášky. Tělesa byla připravena lisovacími tlaky 300, 700 a 1000MPa. Otevřená pórovitost vzorků byla stanovena rtuťovou porozimetrií. Slinování proběhlo ve vysokoteplotním dilatometru. Mikrostruktura byla studována elektronovým mikroskopem. U ZrO2 keramiky klesala slinovací teplota s klesající velikostí částic a s rostoucím lisovacím tlakem. Tato nanokeramika měla po slinování při 1100°C konečnou hustotu vyšší než 99%t.h. a zrna menší než 80nm. Keramika připravená z Al2O3 nanoprášků slinovala špatně, pravděpodobně kvůli vysokému stupni aglomerace prášku.

The influence of particle size and compacting pressure on the microstructure and sinterability of ceramic green bodies were studied. Alumina and zirconia powders with particle size smaller than 35 nm were used and their behaviour was compared with submicrometre sized powders. The green bodies were prepared by cold isostatic pressing at 300, 700 and 1000 MPa. The open porosity of pressed samples was evaluated by mercury intrusion. Specimens were sintered in high temperature dilatometer. The microstructure was examined using electron microscopy. In the case of zirconia ceramics the sintering temperature decreased with decreasing particle size and with increasing compacting pressure. Zirconia nanoceramics exhibited final microstructure with grain size below 80 nm and density exceeding 99 % of theoretical density after sintering at 1100°C. Alumina samples made of nanopowders showed poor sinterability probably due to high level of powder agglomeration.

zirconia, alumina, bulk nanoceramics

2004

01.01.2004

VUTIUM

Brno

80-214-2793-0

Proceedings of the International Conference NAN0 '04

6