8Y-CSZ Zirconia Powder — 8 mol% Yttria Fully-Stabilized Cubic Zirconia (Tosoh TZ-8Y Equivalent)
SEMITECH 8Y-CSZ is a co-precipitated, spray-dried yttria-stabilized zirconia powder containing 8 mol% Y₂O₃ (13.6 wt%), fully stabilizing the cubic fluorite crystal structure at all temperatures from ambient to the melting point. The cubic phase maximizes oxygen-ion vacancy concentration, delivering ionic conductivity of 0.10–0.13 S/cm at 1000°C — the benchmark performance required for solid oxide fuel cell (SOFC) electrolyte membranes, lambda oxygen sensors, and electrochemical oxygen separation systems.
SEMITECH 8Y-CSZ is engineered to match Tosoh TZ-8Y and TZ-8YS specifications on composition, particle size, surface area, and sintering behavior. Available in spray-dried granulated form for dry pressing and attrition-milled submicron powder for tape casting, screen printing, and slurry coating processes used in SOFC membrane fabrication.
Technical Specifications
| Parameter | Unit | Typical Value | Test Method |
|---|---|---|---|
| ZrO₂ + HfO₂ content | wt% | ≥86.0 | XRF (GB/T 26009) |
| Y₂O₃ content | wt% | 13.6 ± 0.30 | XRF |
| HfO₂ content | wt% | ≤2.0 | XRF |
| Al₂O₃ content | wt% | ≤0.10 | XRF |
| SiO₂ | wt% | ≤0.02 | ICP-OES |
| Fe₂O₃ | wt% | ≤0.005 | ICP-OES |
| Na₂O | wt% | ≤0.02 | ICP-OES |
| Loss on ignition (1050°C) | wt% | ≤1.5 | Gravimetric |
| Median particle size d50 (spray-dried) | μm | 30–80 | Laser diffraction (ISO 13320) |
| Median particle size d50 (milled) | μm | 0.3–0.5 | Laser diffraction |
| BET specific surface area | m²/g | 6–12 | N₂ adsorption (ISO 9277) |
| Cubic phase content | % | ≥95 | XRD (Rietveld refinement) |
| Sintered density (1500°C / 4h) | g/cm³ | ≥5.90 | Archimedes method |
| Relative density (sintered) | % | ≥99.0 | — |
| Ionic conductivity (1000°C) | S/cm | 0.10–0.13 | EIS (4-point AC impedance) |
| Ionic conductivity (800°C) | S/cm | 0.03–0.05 | EIS (4-point AC impedance) |
| Thermal expansion coefficient (RT–1000°C) | 10⁻⁶/K | 10.5–11.0 | Dilatometry (ASTM E228) |
Application Suggestions
Solid Oxide Fuel Cell (SOFC) Electrolytes
8Y-CSZ is the industry-standard electrolyte material for intermediate-to-high-temperature SOFCs operating at 700–1000°C. The electrolyte membrane — typically 5–20 μm thick in anode-supported cells or 100–200 μm in electrolyte-supported configurations — must sinter to >99% theoretical density to prevent hydrogen/oxygen gas cross-leakage that would degrade open-circuit voltage. SEMITECH's attrition-milled 8Y-CSZ (d50 0.3–0.5 μm) is optimized for tape casting and screen printing processes used by SOFC stack manufacturers. The powder achieves >99% relative density at 1400–1500°C in air with grain size controlled below 5 μm to maintain mechanical integrity under thermal cycling (>1000 cycles, 20°C ↔ 800°C without delamination).
Thermal Barrier Coatings (TBC)
8Y-CSZ is the standard topcoat material for thermal barrier coatings applied by electron beam physical vapor deposition (EB-PVD) or atmospheric plasma spray (APS) on gas turbine blades and combustion chamber liners. The low thermal conductivity (2.0–2.3 W/m·K for dense material, 0.8–1.2 W/m·K for porous APS coatings) combined with a thermal expansion coefficient (10.5–11.0 × 10⁻⁶/K) closely matching nickel-based superalloy substrates minimizes thermal stress during start-stop cycles. SEMITECH's spray-dried 8Y-CSZ (d50 30–80 μm, flowability per ASTM B213) is formulated for direct use in APS torch feed systems.
Automotive Lambda Oxygen Sensors
Zirconia-based lambda sensors measure exhaust-gas oxygen partial pressure by generating a Nernst voltage across a dense 8Y-CSZ membrane separating the exhaust stream from a reference air chamber. The sensor operates at 300–800°C, requiring fast ionic response (<100 ms) and chemical stability against sulfur, lead, and phosphorus poisons in exhaust gas. SEMITECH 8Y-CSZ meets the purity requirements for automotive sensor-grade zirconia, with Fe₂O₃ ≤0.005 wt% and Na₂O ≤0.02 wt% to prevent electronic conductivity contributions that would introduce measurement error.
Electrochemical Oxygen Pumps and Generators
Dense 8Y-CSZ membranes with deposited platinum or LSM electrodes function as electrochemical oxygen pumps — applying DC voltage drives oxygen ions through the membrane, separating oxygen from air or nitrogen at >99.5% purity. Medical oxygen concentrators, welding gas generators, and laboratory oxygen sources use this principle. SEMITECH 8Y-CSZ provides the consistent sintering behavior required to produce crack-free membranes in disc and tubular geometries.
Technical Support & FAQ: 8Y-CSZ Zirconia Powder
+Q1: What sintering conditions achieve >99% density?
SEMITECH 8Y-CSZ reaches >99% relative density at 1450–1500°C with 2–4 hour hold time and heating/cooling rates of 2–3°C/min. For SOFC electrolyte membranes co-sintered with NiO-YSZ anode supports, constrained sintering effects may require adjustment to 1400–1450°C to match anode shrinkage behavior. SEMITECH provides dilatometry data for sintering profile optimization.
+Q2: How does SiO₂ impurity affect ionic conductivity?
SiO₂ at grain boundaries forms an amorphous silicate glass phase that blocks ionic transport between grains, reducing total conductivity by 10–30% at concentrations above 0.05 wt%. SEMITECH 8Y-CSZ is specified at SiO₂ ≤0.02 wt% to minimize grain-boundary resistance. For applications requiring maximum conductivity, request the low-silica variant (SiO₂ ≤0.005 wt%) at MOQ 100 kg.
+Q3: Is 8Y-CSZ suitable for intermediate-temperature SOFCs operating below 700°C?
At 600–700°C, 8Y-CSZ ionic conductivity drops to 0.01–0.03 S/cm, increasing area-specific resistance to levels that reduce SOFC power density significantly. For IT-SOFC applications below 700°C, doped ceria (GDC/SDC) or scandia-stabilized zirconia (ScSZ) electrolytes offer 3–5× higher conductivity. SEMITECH can source GDC and ScSZ powders on request — contact info@semitechnm.com for alternatives.
+Q4: What are pricing and lead times?
Stock items: 7–14 business days ex-works China, MOQ 25 kg. Pricing is 30–50% below Tosoh TZ-8Y distributor list depending on volume. Low-silica variant: 4–6 week lead time, MOQ 100 kg. Free 1 kg evaluation samples with full CoA (XRF, XRD, PSD, BET) for qualification testing. Payment terms: T/T, L/C, D/P.
Packing & Storage Information
Standard Packing 25 kg multi-wall kraft paper bags with PE inner liner, palletized on standard 1200 × 1000 mm Euro pallets. Net weight per bag: 25.0 ± 0.1 kg.
Bulk Packing 500 kg FIBC (jumbo bags) for SOFC and TBC manufacturers with high-volume consumption. Reduces per-unit handling and packing cost.
Storage Conditions Store in a cool, dry warehouse at <60% RH. 8Y-CSZ powder is hygroscopic — moisture uptake above 0.5 wt% can affect slurry rheology in tape casting applications. Shelf life: 24 months in original sealed packaging.