|
|
Journal of the Korean Ceramic Society 1997;34(9): 915. |
Hot-press법으로 제조된 $Y_2O_3$와 $Nb_2O_5$가 첨가된 정방정 ZrO2의 고온열화 |
이득용, 김대준1, 조경식1 |
대림전문대학 금속재료과 1KIST 세라믹스부 |
High-Temperature Degradation of Hot-Pressed $t-ZrO_2$ Co-doped with $Y_2O_3$ and $Nb_2O_5$ |
|
|
|
|
|
ABSTRACT |
Tetragonal ZrO2 polycrystal (TZP), consisted of 90.24 mol% ZrO2-5.31 mol% Y2O3-4.45 mol% Nb2O5, were prepared using hot-press and mechanical properties and high-temperature degradation were investigated. The specimen, hot-pressed for 1 h at 140$0^{circ}C$ in Ar atmosphere, exhibited flexural strength of 1010 MPa and fracture toughness of 7.5 MPam1/2 and experienced no low-temperature degradation below 40$0^{circ}C$. However, as aged for 100h at temperatures higher than 40$0^{circ}C$, TZP was suffered by high-temperature degradation due to an extensive cavitation caused by the oxidation of carbon. XPS observation revealed that the carbon incorporated in TZPs during hot-pressing exists as either an ether-type CO or a carbonyl-type C=O. Despite of the high-temperature degradation of t-ZrO2 co-doped with Y2O3 and Nb2O5, its flexural strength and fracture toughness were superior to those of the commercial 3 mol% Y2O3-TZP hot-pressed under the identical condition as determined before and after the aging treatments. |
Key words:
Tetragonal $ZrO_1$ Polycrystal (TZP), High-Temperature Degradation, Co, $Co_2$, Oxidation |
|
|
|