The role of Yttrium oxide

Materials science
Yttrium oxide is the most important yttrium compound and is widely used to make YVO4 europium and Y2O3 europium phosphors that give the red color in color TV picture tubes. Yttrium oxide is also used to make yttrium iron garnets, which are very effective microwave filters.
Yttrium oxide is used to make the high temperature superconductor YBa2Cu3O7, known as "1-2-3" to indicate the ratio of the metal constituents:
2 Y2O3 + 8 BaO + 12 CuO + O2 → 4 YBa2Cu3O7
This synthesis is typically conducted at 800 °C.
The thermal conductivity of yttrium oxide is 27 W/(m•K).
Inorganic synthesis
Yttrium oxide is an important starting point for inorganic compounds. For organometallic chemistry it is converted to YCl3 in a reaction with concentrated hydrochloric acid and ammonium chloride.
Lasers
Yttrium oxide ceramics is a prospective solid-state laser material. In particular, lasers with ytterbium as dopant allow the efficient operation both in cw operation and in pulsed regimes. At high concentration of excitations (of order of 1%) and poor cooling, the quenching of emission at laser frequency and avalanche broadband emission takes place.