ZrO2 refractories Flashcards
1
Q
What is added to ZrO2 refractories? Why?
A
~ Y2O3, MgO, or CaO are added to form a solid solution upon firing that has cubic symmetry over broad temp range
~ if it didn’t have cubic symmetry, the 3-4 vol% change w/ monoclinic–> tetragonal polymorphic transf. would cause it to crack
2
Q
What are the characteristics of stabilized zirconia?
A
~ stable against acidic and basic slags and molten Fe
~expensive, but good erosion and thermal shock resistance
3
Q
What are stabilized zirconia refractories used in?
A
~ metering nozzles, slide gate valves in steel manufacture
~ glass tanks for corrosive glass fiber compositions as they are not easily wetted by molten glass
