Yttria-Stabilized Zirconia (YSZ) Powder: 3Y-TZP & 8Y-CSZ Grades — Tosoh TZ-Series Equivalents
Yttria-stabilized zirconia powders engineered to match Tosoh TZ-3Y and TZ-8Y specifications — spray-dried and attrition-milled grades for structural ceramics, dental prosthetics, SOFC electrolytes, and thermal barrier coatings.
Contents
| 2 | Tosoh TZ-equiv. | 30–50% |
|---|---|---|
| YSZ Grades | Performance Benchmark | Cost Advantage |
YSZ Powder Technology: Stabilization Mechanisms & Phase Control
Pure zirconia undergoes a destructive monoclinic-to-tetragonal phase transformation at approximately 1170°C, accompanied by a 3–5% volume expansion that causes catastrophic cracking in sintered bodies. Adding yttria (Y₂O₃) as a stabilizer suppresses this transformation and locks in the desired crystal phase at room temperature.
At 3 mol% Y₂O₃ (5.15 wt%), the tetragonal phase is metastably retained — this is 3Y-TZP (tetragonal zirconia polycrystal). The metastability is functional: under mechanical stress, tetragonal grains at a crack tip transform to monoclinic, expanding locally and compressing the crack shut. This transformation toughening mechanism delivers fracture toughness of 8–12 MPa·m^0.5, among the highest of any oxide ceramic.
At 8 mol% Y₂O₃ (13.6 wt%), the cubic fluorite phase is fully stabilized — this is 8Y-CSZ (cubic stabilized zirconia). The cubic phase eliminates transformation toughening but maximizes oxygen-ion vacancy concentration, yielding ionic conductivity of 0.10–0.13 S/cm at 1000°C. This makes 8Y-CSZ the standard electrolyte material for solid oxide fuel cells (SOFC), oxygen sensors, and electrochemical oxygen pumps.
SEMITECH's YSZ powders are produced by co-precipitation of zirconium and yttrium salts followed by calcination and spray drying (granulated grades) or attrition milling (submicron grades). The co-precipitation route ensures atomic-level mixing of Y₂O₃ throughout the ZrO₂ lattice — a prerequisite for uniform phase distribution and consistent sintering behavior.
3Y-TZP — Tetragonal Zirconia for Mechanical Applications
3Y-TZP is the workhorse grade for applications demanding high strength and toughness in an oxide ceramic body. Key specifications:
| Parameter | Value | Test Method |
|---|---|---|
| ZrO₂ + HfO₂ | ≥94.5 wt% | XRF |
| Y₂O₃ | 5.15 ± 0.20 wt% | XRF |
| Al₂O₃ | 0.25 ± 0.10 wt% | XRF |
| SiO₂ | ≤0.02 wt% | ICP-OES |
| Fe₂O₃ | ≤0.01 wt% | ICP-OES |
| Na₂O | ≤0.04 wt% | ICP-OES |
| d50 (spray-dried granule) | 30–80 μm | Laser diffraction |
| d50 (attrition-milled) | 0.3–0.6 μm | Laser diffraction |
| BET surface area | 7–15 m²/g | N₂ adsorption (ISO 9277) |
| Sintered density | ≥6.05 g/cm³ | Archimedes method |
| Flexural strength (sintered) | ≥1000 MPa | 3-point bend (ISO 6872) |
| Fracture toughness | 8–12 MPa·m^0.5 | SEVNB / IF method |
Primary applications include dental crowns and bridges (CAD/CAM milled from pre-sintered blanks), structural ceramic components for semiconductor equipment, optical fiber ferrules and sleeves, precision valve and pump components, and wear-resistant cutting tools.
The 0.25 wt% Al₂O₃ addition acts as a sintering aid, reducing the required sintering temperature from 1550°C to approximately 1450°C while inhibiting grain growth — critical for maintaining the fine-grained microstructure (grain size <0.5 μm) that enables transformation toughening.
8Y-CSZ — Cubic Zirconia for Ionic Conduction
8Y-CSZ is optimized for maximum oxygen-ion conductivity at elevated temperatures, serving electrochemical applications where ionic transport through a dense ceramic membrane is the functional requirement:
| Parameter | Value | Test Method |
|---|---|---|
| ZrO₂ + HfO₂ | ≥86.0 wt% | XRF |
| Y₂O₃ | 13.6 ± 0.30 wt% | XRF |
| Al₂O₃ | ≤0.10 wt% | XRF |
| SiO₂ | ≤0.02 wt% | ICP-OES |
| d50 (spray-dried) | 30–80 μm | Laser diffraction |
| d50 (attrition-milled) | 0.3–0.5 μm | Laser diffraction |
| BET surface area | 6–12 m²/g | N₂ adsorption (ISO 9277) |
| Sintered density | ≥5.90 g/cm³ | Archimedes method |
| Ionic conductivity (1000°C) | 0.10–0.13 S/cm | EIS (4-point) |
Primary applications: SOFC electrolyte membranes (anode-supported and electrolyte-supported configurations), thermal barrier coatings (EB-PVD and APS routes), lambda oxygen sensors for automotive exhaust, and electrochemical oxygen pumps for medical and industrial gas separation.
For SOFC applications, the powder must sinter to >99% theoretical density to prevent gas cross-leakage through the electrolyte membrane. SEMITECH's 8Y-CSZ achieves this at 1400–1500°C in air, with grain size controlled below 5 μm to maintain mechanical integrity under thermal cycling.
Grade Comparison — Buyer Specification Reference
Side-by-side comparison of SEMITECH YSZ grades against their Tosoh TZ-series equivalents.
| Parameter | SEMITECH 3Y-TZP | Tosoh TZ-3YS-E | SEMITECH 8Y-CSZ | Tosoh TZ-8YS |
|---|---|---|---|---|
| Y₂O₃ (wt%) | 5.15 ± 0.20 | 5.15 ± 0.20 | 13.6 ± 0.30 | 13.3 ± 0.50 |
| Al₂O₃ (wt%) | 0.25 ± 0.10 | 0.25 ± 0.10 | ≤0.10 | ≤0.05 |
| d50 (μm) | 0.3–0.6 | 0.4–0.6 | 0.3–0.5 | 0.4–0.5 |
| BET (m²/g) | 7–15 | 7–10 | 6–12 | 6–8 |
| Sintered density (g/cm³) | ≥6.05 | ≥6.05 | ≥5.90 | ≥5.90 |
| Price index | 100 | 150–180 | 100 | 160–200 |
Note: Price index is normalized to SEMITECH = 100. Tosoh pricing reflects 2025–2026 distributor list prices for standard MOQ. Actual landed cost varies by destination and volume.
Supply Chain: Tosoh Alternative Sourcing
Tosoh has dominated the global YSZ powder market for three decades through its TZ-series products manufactured at the Nanyo complex in Yamaguchi Prefecture, Japan. Since 2024, capacity constraints and allocation protocols have extended Tosoh lead times to 16–24 weeks, creating qualification urgency for alternative sources among ceramic component manufacturers and dental blank producers worldwide.
SEMITECH addresses this by maintaining qualified relationships with three Chinese YSZ producers operating co-precipitation and spray-drying lines at combined capacity exceeding 5,000 MT/year. Each producer undergoes annual audit covering raw material traceability (zircon sand origin, Y₂O₃ purity), process control (calcination temperature profile, spray-drying parameters), and QC capability (XRD phase quantification, PSD by laser diffraction, BET by N₂ adsorption).
For buyers running qualification programs, SEMITECH provides: 1 kg evaluation samples with full analytical data package, technical support for sintering profile optimization, and side-by-side comparison data against Tosoh TZ-series benchmarks. Contact info@semitechnm.com for sample requests.
FAQ
+What is the difference between 3Y-TZP and 8Y-CSZ?
3Y-TZP contains 3 mol% (5.15 wt%) yttria, retaining the tetragonal crystal phase for maximum mechanical strength and fracture toughness (≥1000 MPa, 8–12 MPa·m^0.5). It is used for structural and dental ceramics. 8Y-CSZ contains 8 mol% (13.6 wt%) yttria, fully stabilizing the cubic phase for maximum oxygen-ion conductivity (0.10–0.13 S/cm at 1000°C). It is used for SOFC electrolytes and oxygen sensors. The two grades are not interchangeable — specifying the wrong stabilization level will result in either mechanical failure or inadequate ionic conductivity.
+Can SEMITECH YSZ powders directly replace Tosoh TZ-3Y in existing sintering profiles?
In most cases, yes. SEMITECH 3Y-TZP matches Tosoh TZ-3YS-E on Y₂O₃ content, Al₂O₃ sintering aid level, d50, and BET surface area. However, minor differences in powder morphology may require sintering profile adjustment of ±10–20°C and ±15 minutes to achieve identical density. SEMITECH provides sintering optimization guidance and test-sintering data for customers transitioning from Tosoh supply.
+What powder form should I specify — spray-dried or attrition-milled?
Spray-dried granulated powder (d50 30–80 μm, free-flowing) is designed for dry pressing and CIP operations where good die filling and uniform green density are required. Attrition-milled submicron powder (d50 0.3–0.6 μm) is designed for slip casting, tape casting, and ceramic injection molding where colloidal stability and high green packing density are needed. Both forms are available for 3Y-TZP and 8Y-CSZ grades.
+What are typical lead times and MOQ?
Stock items: 7–14 business days ex-works China, MOQ 25 kg. Custom specifications or non-standard Y₂O₃ content: 4–6 weeks, MOQ 100 kg. Annual supply agreements with quarterly call-off scheduling are available for volumes above 1 MT/year.
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