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Alumina 99.5 vs Zirconia Y-TZP

Ceramic · grade comparison

Alumina 99.5 and Zirconia Y-TZP are both ceramic grades. Zirconia Y-TZP is the stronger of the two: tensile strength 450 MPa (65.3 ksi) against 260 MPa (37.7 ksi) for Alumina 99.5, about 73% more. Alumina 99.5 is harder — 1,650 HV against 1,250 HV for Zirconia Y-TZP — which matters for wear surfaces and threads. Alumina 99.5 is lighter (3.9 g/cm³ vs 6.05 g/cm³ for Zirconia Y-TZP) and Alumina 99.5 is stiffer (372 GPa vs 210 GPa).

Alumina 99.5Choose it when surface hardness matters, or when weight is the constraint.

Zirconia Y-TZPChoose it when strength drives the design.

Alumina 99.5 vs Zirconia Y-TZP: properties

Alumina 99.5Zirconia Y-TZP

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

372 GPa54 Msi
210 GPa30.5 Msi

Shear Modulus

152 GPa22 Msi
80 GPa11.6 Msi

Bulk Modulus

228 GPa33.1 Msi
184 GPa26.7 Msi

Poisson's Ratio

0.22
0.31

Tensile Strength (Ultimate)

260 MPa37.7 ksi
450 MPa65.3 ksi

Compressive Strength

2,500 MPa363 ksi
2,100 MPa305 ksi

Flexural Strength

350 MPa50.8 ksi
1,000 MPa145 ksi

Shear Strength

330 MPa47.9 ksi
—

Fracture Toughness (K_IC)

4 MPa·√m3.6 ksi·√in
9 MPa·√m8.2 ksi·√in

Hardness, Vickers

1,650 HV
1,250 HV

Hardness, Knoop

1,440 HK
1,150 HK

Hardness, Mohs

9
8.5

Elongation at Break

—
0%

Physical

Density and transition temperatures.

Density

3.9 g/cm³0.14 lb/in³
6.05 g/cm³0.22 lb/in³

Melting Point (Solidus)

2,050°C3,722 °F
2,700°C4,892 °F

Refractive Index

1.76
2.17

Same in both: Porosity 0.1%

Thermal

How each material carries heat and how hot it can run.

Thermal Conductivity

32 W/m·K18.5 BTU/hr·ft·°F
2.5 W/m·K1.4 BTU/hr·ft·°F

Specific Heat Capacity

880 J/kg·K0.21 BTU/lb·°F
450 J/kg·K0.11 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

7 µm/m·K3.9 µin/in·°F
10.3 µm/m·K5.7 µin/in·°F

Max Service Temperature (continuous)

1,700°C3,092 °F
1,000°C1,832 °F

Min Service Temperature

-269°C-452 °F
-200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹³ Ω·m3.94×10²⁰ µΩ·in
1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in

Dielectric Strength

17 kV/mm432 V/mil
12 kV/mm305 V/mil

Dielectric Constant (1 MHz)

9.8
28

Dissipation Factor (1 MHz)

2×10⁻⁴
0.003

Volume Resistivity

1×10¹⁵ Ω·cm
1×10¹² Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Same in both: Corrosion Resistance 95 / 100

Manufacturability

FabDigit workshop ratings (0–100 scores) — how each material behaves on the machine.

Machinability

5 / 100
4 / 100

Polishability

88 / 100
95 / 100

Sintering / Firing Temperature

1,650°C3,002 °F
1,450°C2,642 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

52 MJ/kg22,356 BTU/lb
90 MJ/kg38,693 BTU/lb

Embodied Carbon (primary production)

3 kg CO₂/kg
6 kg CO₂/kg

Embodied Water

200 L/kg24 gal/lb
150 L/kg18 gal/lb

Typical Recycled Content

0%
1%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

67 kN·m/kg
74 kN·m/kg

Specific Stiffness (E / density)

95.4 MN·m/kg
34.7 MN·m/kg

Thermal Diffusivity

9.3 mm²/s
0.9 mm²/s

Thermal Shock Resistance Index

3
1

Strength versus weight

Yield strength against density for every ceramic grade in the FabDigit library; the compared grades are highlighted. Up and left is stronger for its weight.

501002005001,000234567Density (g/cm³)Yield strength (MPa) — log scaleAlumina 99.5Zirconia Y-TZP

Manufacturing and finishing

CapabilityAlumina 99.5Zirconia Y-TZP
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Alumina 99.5 vs Zirconia Y-TZP — frequently asked

Is Zirconia Y-TZP stronger than Alumina 99.5?

Yes. Zirconia Y-TZP has a typical tensile strength of 450 MPa (65.3 ksi) against 260 MPa (37.7 ksi) for Alumina 99.5 — about 73% more.

Which is cheaper, Alumina 99.5 or Zirconia Y-TZP?

Both sit in the same relative cost tier ($$$$, high); the part price will be decided by machining time, tolerance and quantity rather than by the material.

When should I choose Alumina 99.5 over Zirconia Y-TZP?

Pick Alumina 99.5 when surface hardness matters, or when weight is the constraint. Pick Zirconia Y-TZP when strength drives the design.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Alumina 99.5 and Zirconia Y-TZP side by side — material, machining time, tolerance and finish in one quote. Certified material data ships with the order on request.

Typical handbook values for the conditions named above, normalised for comparison. Hardness on non-Brinell scales is converted approximately for charting only. Request certified data with your order for design-critical properties.