Yttrium oxide

Yttrium oxide (CAS 1314-36-9), also known as yttrium(III) oxide and diyttrium trioxide (Y₂O₃), is a high-melting, white crystalline solid in the rare earth oxides family.

Where is Yttrium oxide used?

• Electronics and solar PV: host matrix for europium-activated phosphors (Y₂O₃:Eu) and plasma chamber coating in semiconductor etch tools, resisting fluorine and chlorine plasmas
• Sputter targets of dense yttria deposit dielectric and protective oxide films
• Aerospace and defence: primary raw material for thermal barrier coatings (TBC) applied by air plasma spray and a constituent of yttria-stabilised zirconia (YSZ) turbine components
• Oil, gas and energy: feedstock for solid oxide fuel cell (SOFC) electrolyte production
• Building and construction: stabiliser in structural and dental zirconia ceramics and sintering aid for silicon nitride (Si₃N₄) and silicon carbide (SiC) technical ceramics
• Optical glass manufacturers use yttria as a refractive-index modifier.

Good to know: Particle size is a critical specification variable. Not to be confused with other rare earth oxides.

Commercial specifications

• Cubic bixbyite crystal structure; true density approximately 5.01–5.1 g/cm³; melting point around 2,430 °C
• Purity grades 2N (99 % Y₂O₃/TREO) to 6N (99.9999 % Y₂O₃/TREO), quoted on a TREO basis with TREO ≥ 99 %
• Loss on ignition (LOI) typically ≤ 1 %; residual rare earth and non-rare-earth impurities characterised at ppm level
• Micronised grades d₅₀ 1–2 µm for plasma spray and thin-film; standard powder d₅₀ 2–10 µm for ceramic and sintering; nanoscale powder available; forms include free-flowing powder, ready-to-press (RTP) granules, plasma spray granules, sputter targets; packaging 1 kg laboratory bags, 25 kg fibre or plastic drums, FIBC palletised; REACH registration in the 100–1,000 t/a tonnage band