Abstract
The reaction of molten steel with CaO stabilized and MgO stabilized ZrO2－C in an argon atmosphere at 1560℃
for 60min was examined. Molten steel penetrated into the side of the CaO stabilized ZrO2－C crucible up to 2－3 mm depth, where a ZrC coating layer was formed on the ZrO2 particles, whereas did not into the MgO stabilized ZrO2－C crucible. The wettabilities of porous ZrO2 and porous ZrC by molten steel were measured. Molten steel wet the ZrO2 poorly, but wet the ZrC well so that the molten steel drop completely infiltrated the ZrC substrate. These results indicate that the ZrC coating layer caused molten steel penetration to the CaO stabilized ZrO2－C crucible for the good wettability between molten steel and ZrC. Thermodynamically, ZrC is formed by the reaction between ZrO2 and carbon under condition of PCO＜0.035MPa（at 1560℃） ＿ . In the case of MgO stabilized ZrO2－C, it is difficult to form ZrC because of the reaction of MgO with carbon. MgO stabilized ZrO2－C nozzle was tested on an actual steel continuous casting, and showed higher corrosion resistance than CaO stabilized ZrO2－C nozzle.
