The surface tension of, and the contact angle formed by, molten iron on three types of commercial zirconia substrates containing 8 mol% Y2O3, 9 mol% MgO, or 11 mol% CaO were measured over a wide range of oxygen concentration in the molten iron by the sessile drop method. The solidified metal–substrate interface was examined in an SEM equipped with an EPMA. The surface tension of molten iron decreased with increasing oxygen concentration. The contact angle of molten iron increased rapidly with increasing oxygen concentration and reached a local maximum value at an oxgyen concentration of ∼100 ppm, and then decreased with increasing oxygen concentration. At lower oxygen concentration, dissociation of ZrO2 was observed. For the ZrO2–9 mol% MgO substrate, segregation of MgO to the interface was observed. For the ZrO2–11 mol% CaO substrate, segregation of CaO and the precipitation of small ZrO2 particles in the segregation layer of CaO were observed at the interface. Conversely, at higher oxygen concentration, penetration of molten iron into the grain boundaries was observed in all types of zirconia substrates.
|Number of pages||9|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - Dec 1993|
All Science Journal Classification (ASJC) codes
- Ceramics and Composites
- Materials Chemistry