Yttria/ Zirconia
Yttria-stabilised zirconia (YSZ) is a spray-grade ceramic powder engineered for thermal spray deposition of thermal barrier coatings (TBCs) and wear-resistant ceramic layers. Formulated at the industry-standard 7-8 wt% Y2O3 doping level, this partially stabilised zirconia locks in a metastable tetragonal-prime microstructure that resists the destructive phase transformation which plagues undoped zirconia under thermal cycling. Available in hollow spherical (HOSP), agglomerated-and-sintered, and fused-and-crushed morphologies, the powder is built for consistent hopper flow and predictable melting in air plasma spray (APS) and HVOF equipment. It is the same class of material that protects turbine blades, combustor liners, and hot-section hardware across the aerospace and power-generation industries. Custom particle size cuts, purity grades, and packaging are available for OEM and MRO qualification programs.
| Particle size d50(μm) : | 40- 60 µm |
| Purity (%) : | >99.8% |
Introduction to Yttria-Stabilized Zirconia
Yttria-Stabilized Zirconia (YSZ, 7–8 wt% Y₂O₃) is a partially stabilised zirconia engineered to prevent the damaging monoclinic–tetragonal phase transformation and its associated 3–5% volume change. Y³⁺ substitution for Zr⁴⁺ creates oxygen vacancies that stabilise the tetragonal-prime (t′) phase with a minor cubic component, providing an effective balance of phase stability, thermal-cycling resistance, and low thermal conductivity. Unlike dense sputtering targets, spray-grade YSZ is engineered as feedstock powder with controlled particle size and morphology. Air plasma spraying (APS) is the primary deposition method, producing porous, thermally insulating coatings typically 100–500 µm thick. HOSP, agglomerated-sintered, and fused-crushed powders offer different melting and microstructural characteristics for turbine-engine thermal barrier coatings and high-temperature wear protection.
FAQs
Question: Why yttria doped in zirconia?
Answer: Because of stabilization, yttria doped in zirconia increases its tetragonal phase and ionic conduction, improving its mechanical properties for high-temperature applications.
Question: Which thermal spray process should I use — APS or HVOF?
Answer: Air plasma spray (APS) is the standard process for thermal barrier coatings because it produces the segmented, porous microstructure that gives low thermal conductivity. HVOF is generally reserved for denser, less porous wear-resistant zirconia coatings from agglomerated or fused-and-crushed grades.
Question: Why does the powder contain a small amount of HfO2?
Answer: Hafnium is chemically almost identical to zirconium and occurs together with it in natural ore, so commercial-grade zirconia typically carries roughly 1.5-2% HfO2 as an inseparable co-constituent rather than a contaminant. It does not measurably affect thermal spray or TBC performance, and 'high-purity' zirconia specs are conventionally expressed as ZrO2+HfO2.
Introduction to Yttria-Stabilized Zirconia
Yttria-Stabilized Zirconia (YSZ, 7–8 wt% Y₂O₃) is a partially stabilised zirconia engineered to prevent the damaging monoclinic–tetragonal phase transformation and its associated 3–5% volume change. Y³⁺ substitution for Zr⁴⁺ creates oxygen vacancies that stabilise the tetragonal-prime (t′) phase with a minor cubic component, providing an effective balance of phase stability, thermal-cycling resistance, and low thermal conductivity. Unlike dense sputtering targets, spray-grade YSZ is engineered as feedstock powder with controlled particle size and morphology. Air plasma spraying (APS) is the primary deposition method, producing porous, thermally insulating coatings typically 100–500 µm thick. HOSP, agglomerated-sintered, and fused-crushed powders offer different melting and microstructural characteristics for turbine-engine thermal barrier coatings and high-temperature wear protection.
Key Properties of Yttria-Stabilized Zirconia
| Property | Value | Significance |
|---|
| CAS Number | 114168-16-0 | Registered as a variable-composition (UVCB) substance covering the Zr-Y-O system; used for regulatory/procurement identification, not as proof of a single fixed formula |
| Purity | 99.5% – 99.9% metals basis (excl. natural co-occurring HfO2) | Controls contaminant-driven sintering/porosity defects and coating consistency for aerospace-qualified TBC lots |
| Particle size distribution | 40-60 µm typical D50; commercial cuts span ~15-106 µm | Governs powder feed rate, in-flight melting behaviour, and final coating porosity/thickness |
| Morphology | HOSP (hollow spherical), agglomerated & sintered, or fused & crushed | Determines melting efficiency, deposit density, and suitability for APS vs. HVOF |
| Flowability (Hall flow) | Typically 10-20 s/50 g per ASTM B213 for free-flowing spray grades | Ensures uniform, non-bridging feed through the spray gun powder hopper and feed lines |
| Density | True: 5.9-6.1 g/cm³; as-sprayed coating: 5.1-5.4 g/cm³ (~85-90% dense) | Engineered porosity in the sprayed coating is what lowers thermal conductivity for TBC insulation |
| Crystal structure/phase | Metastable tetragonal-prime (t’) with minor cubic; avoids monoclinic | Non-transformable t’ phase prevents the destructive volume-change cracking that plagues undoped zirconia |
| Melting point / thermal conductivity | ~2700°C (host ZrO2); ~0.8-1.2 W/m·K as-sprayed (porous) | High melting point survives hot-section service; low conductivity is the core TBC insulating function |
Types & Grades of Yttria-Stabilized Zirconia
Yttria-Stabilized Zirconia powder is offered in standard catalogue grades and particle size distributions, with custom purity, morphology, and packaging available for OEM and R&D use.
| Grade / Form | Typical Purity | Key Features / Uses |
|---|
| 7-8YSZ HOSP (e.g., 204NS-type) | 99.5%+ | Hollow spherical particles for standard air-plasma-sprayed thermal barrier coatings on turbine blades and vanes |
| 7-8YSZ Agglomerated & Sintered | 99.5%+ | Denser, robust feedstock suited to both APS and HVOF; higher deposit density than HOSP grades |
| High-purity 7-8YSZ (low-alkali) | 99.9% | Reduced alkali/alkaline-earth impurities for OEM-specified aerospace and critical-application TBC programs |
| Fine-cut 7-8YSZ (-45 µm) | 99.5%+ | Finer particle size for thinner, smoother coatings and finer as-sprayed microstructure |
| Fully-stabilized cubic zirconia (~20 wt% Y2O3) | 99.5%+ | Single-phase cubic structure for abradable seal and high-temperature-stability applications where toughening is not required |
Applications of Yttria-Stabilized Zirconia
Yttria-Stabilized Zirconia powder supports demanding roles across research and production applications where this material’s specific structural, electronic, magnetic, or electrochemical properties are the key requirement.
| Industry | Application | Function |
|---|
| Commercial & military aerospace | Thermal barrier coatings on turbine blades, vanes, and combustor liners | Insulates superalloy substrates from combustion-gas temperatures, extending hot-section component life |
| Power generation | TBCs for land-based industrial gas turbine hot-gas-path components | Allows higher turbine firing temperatures and reduced cooling-air requirements, improving efficiency |
| Oil & gas / industrial turbines | Combustor and transition-piece thermal/corrosion barrier coatings | Protects hardware from thermal cycling, hot corrosion, and oxidation in continuous-duty service |
| Automotive & advanced engines | Exhaust manifold, turbocharger housing, and piston-crown TBCs (production and R&D) | Reduces heat rejection to surrounding components and improves thermal efficiency |
| Industrial wear applications | Coatings on valve seats, pump sleeves, and plunger surfaces | Provides a hard, chemically inert, erosion- and corrosion-resistant working surface |
| Aftermarket MRO / overhaul | Blade-tip and hot-section repair/re-coating during engine overhaul | Restores dimensional tolerance and thermal protection on refurbished components |
Why Partner with Infinita Materials?
- Technical Depth: in-house quality control with ICP-MS and XRF purity verification, particle size distribution and density measurement, and full certificates of analysis on every lot.
- Global Logistics: reliable supply from single R&D-scale quantities to production-line volumes, with established international shipping.
- Responsive Support: direct access to materials engineers for grade, particle size, and packaging selection, and process-compatibility questions.
Take the Next Step
Infinita Materials manufactures Yttria-Stabilized Zirconia powder engineered to the purity, particle size, and morphology your process requires. Whether the requirement is a standard catalogue grade or a custom particle size distribution, purity, or packaging format, our team can help match the right specification to your process. Request a quote or speak with our technical team to discuss your material specification.
Frequently Asked Questions
Why yttria doped in zirconia?
Because of stabilization, yttria doped in zirconia increases its tetragonal phase and ionic conduction, improving its mechanical properties for high-temperature applications.
Which thermal spray process should I use — APS or HVOF?
Air plasma spray (APS) is the standard process for thermal barrier coatings because it produces the segmented, porous microstructure that gives low thermal conductivity. HVOF is generally reserved for denser, less porous wear-resistant zirconia coatings from agglomerated or fused-and-crushed grades.
Why does the powder contain a small amount of HfO2?
Hafnium is chemically almost identical to zirconium and occurs together with it in natural ore, so commercial-grade zirconia typically carries roughly 1.5-2% HfO2 as an inseparable co-constituent rather than a contaminant. It does not measurably affect thermal spray or TBC performance, and 'high-purity' zirconia specs are conventionally expressed as ZrO2+HfO2.
Yttria/ Zirconia
Used in Various Industries
Biomedical
Energy
Aerospace
Automotive
Healthcare
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