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Al2O3-96 vs Synthetic Sapphire

Ceramic · grade comparison

Al2O3-96 and Synthetic Sapphire are both ceramic grades. Synthetic Sapphire is the stronger of the two: tensile strength 400 MPa (58 ksi) against 170 MPa (24.7 ksi) for Al2O3-96, about 135% more. Synthetic Sapphire is harder — 2,000 HV against 1,150 HV for Al2O3-96 — which matters for wear surfaces and threads. Al2O3-96 is lighter (3.72 g/cm³ vs 3.98 g/cm³ for Synthetic Sapphire) and Synthetic Sapphire is stiffer (400 GPa vs 300 GPa).

Al2O3-96Choose it when weight is the constraint.

Synthetic SapphireChoose it when strength drives the design, or when surface hardness matters.

Al2O3-96 vs Synthetic Sapphire: properties

Al2O3-96Synthetic Sapphire

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

300 GPa43.5 Msi
400 GPa58 Msi

Shear Modulus

124 GPa18 Msi
165 GPa23.9 Msi

Bulk Modulus

180 GPa26.1 Msi
250 GPa36.3 Msi

Poisson's Ratio

0.21
0.28

Tensile Strength (Ultimate)

170 MPa24.7 ksi
400 MPa58 ksi

Elongation at Break

0%
—

Compressive Strength

2,100 MPa305 ksi
2,000 MPa290 ksi

Flexural Strength

350 MPa50.8 ksi
700 MPa102 ksi

Shear Strength

200 MPa29 ksi
480 MPa69.6 ksi

Fracture Toughness (K_IC)

3.5 MPa·√m3.2 ksi·√in
2.5 MPa·√m2.3 ksi·√in

Hardness, Vickers

1,150 HV
2,000 HV

Hardness, Knoop

1,100 HK
1,900 HK

Same in both: Hardness, Mohs 9

Physical

Density and transition temperatures.

Density

3.72 g/cm³0.13 lb/in³
3.98 g/cm³0.14 lb/in³

Melting Point (Solidus)

1,750°C3,182 °F
2,053°C3,727 °F

Porosity

0.2%
0%

Refractive Index

—
1.768

Light Transmission

—
86%

Thermal

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

Thermal Conductivity

24 W/m·K13.9 BTU/hr·ft·°F
35 W/m·K20.2 BTU/hr·ft·°F

Specific Heat Capacity

880 J/kg·K0.21 BTU/lb·°F
760 J/kg·K0.18 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

6.5 µm/m·K3.6 µin/in·°F
5.6 µm/m·K3.1 µin/in·°F

Max Service Temperature (continuous)

1,500°C2,732 °F
1,600°C2,912 °F

Min Service Temperature

-200°C-328 °F
-269°C-452 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹⁴ Ω·m3.94×10²¹ µΩ·in

Dielectric Strength

15 kV/mm381 V/mil
48 kV/mm1,219 V/mil

Dissipation Factor (1 MHz)

3×10⁻⁴
1×10⁻⁴

Volume Resistivity

1×10¹⁴ Ω·cm
1×10¹⁶ Ω·cm

Same in both: Dielectric Constant (1 MHz) 9.4

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

90 / 100
96 / 100

Manufacturability

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

Machinability

5 / 100
4 / 100

Polishability

70 / 100
98 / 100

Sintering / Firing Temperature

1,600°C2,912 °F
2,100°C3,812 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

52 MJ/kg22,356 BTU/lb
950 MJ/kg408,427 BTU/lb

Embodied Carbon (primary production)

3.2 kg CO₂/kg
60 kg CO₂/kg

Embodied Water

150 L/kg18 gal/lb
400 L/kg47.9 gal/lb

Typical Recycled Content

2%
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

46 kN·m/kg
101 kN·m/kg

Specific Stiffness (E / density)

80.6 MN·m/kg
100.5 MN·m/kg

Thermal Diffusivity

7.3 mm²/s
11.6 mm²/s

Thermal Shock Resistance Index

2
6

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 scale

Manufacturing and finishing

CapabilityAl2O3-96Synthetic Sapphire
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Al2O3-96 vs Synthetic Sapphire — frequently asked

Is Synthetic Sapphire stronger than Al2O3-96?

Yes. Synthetic Sapphire has a typical tensile strength of 400 MPa (58 ksi) against 170 MPa (24.7 ksi) for Al2O3-96 — about 135% more.

Which is cheaper, Al2O3-96 or Synthetic Sapphire?

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 Al2O3-96 over Synthetic Sapphire?

Pick Al2O3-96 when weight is the constraint. Pick Synthetic Sapphire when strength drives the design, or when surface hardness matters.

Ready to make it?

Upload a CAD file and FabDigit prices the part in Al2O3-96 and Synthetic Sapphire 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.