Zirconium Dioxide - Zirconia - ZrO2

Acid Unit 6 Topic 16
Oxide Qualities

Opacifier - very dense white


  • An opacifier similar to tin oxide.
  • Better than tin in reduction - not subject to chromium flashing.
  • 50% ZrO2 with 50% tin oxide gives good results
  • Mostly not dissolved rather remaining in suspension.


  • Zirconium dioxide.
  • Zirconium silicate (ZrO2.SiO2) - the preferred material as it disperses more easily giving better opacity.
  • Commercial forms of zirconium silicate in which the powder is coated with a dispersal medium - Ultrox, Zircopax, Opax.

Colour Response

  • Gives extreme whites lacking the softer quality of tin oxide.
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