Fully stabilized zirconia

Question 1

How is fully stabilized zirconia processed?

Answer 1

~ powders are sintered or hot pressed at 1800C, of compositions within the cubic phase field (with MgO stabilizer additions)

~ like Al, Zr has very low nobility (very high affinity for oxygen), so ZrO2 can be sintered in inert/vacuum/reducing atmospheres

Question 2

How is the cubic phase maintained?

Answer 2

~ can be retained as a metastable phase (the time required for the diffusion needed to form conjugate phases is not permitted), avoiding the transformation to monoclinic which wold otherwise crack up the sintered body

Question 3

What is the effect of Y2O3 additions?

Answer 3

~ result in the cubic form being the stable phase down to room temp

Question 4

What are the applications?

Answer 4

~fully stabilized zirconia is used as refractories (brick, foam, or fiber wool), heating elements, and grown single crystal gemstones