Zirconia nozzle is used as continuous casting nozzle in steel production. It is characterized by high melting point, good corrosion resistance to molten steel and slag, and long service life. Its life is closely related to the zirconia content: With high zirconium oxide content, the zirconia ceramic of inner core will have higher density, in that case, the anti-erosion and erosion resistance of nozzle will be stronger. In terms of improving the thermal shock resistance, generally semi-stabilized zirconia will be used for that, stabilizer is calcium oxide, yttrium oxide may also be used to stabilized zirconia in special circumstances.
Zirconium oxide is the main raw material of refractory material zirconia nozzle, its chemical composition:
1)ZrO2 content: 60%
2)ZrO2 content: 65%
3)ZrO2 content: 75%
4)ZrO2 content: 85%
5)ZrO2 content: 95%
Zirconia binder is added, after kneading, press it on the hydraulic press molding. Semi-finished products are fired in temperature above 1700C.
Material requirements of zirconia sizing nozzle are:
(1) Good erosion-resistant to molten steel and slag.
(2) Better thermal shock resistance.