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Alumina 99.5 vs ZTA

Ceramic · grade comparison

Alumina 99.5 and ZTA are both ceramic grades. Alumina 99.5 is harder — 1,650 HV against 1,500 HV for ZTA — which matters for wear surfaces and threads. Alumina 99.5 is lighter (3.9 g/cm³ vs 4.15 g/cm³ for ZTA) and Alumina 99.5 is stiffer (372 GPa vs 350 GPa).

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

Alumina 99.5 vs ZTA: properties

Alumina 99.5ZTA

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

372 GPa54 Msi
350 GPa50.8 Msi

Shear Modulus

152 GPa22 Msi
143 GPa20.7 Msi

Bulk Modulus

228 GPa33.1 Msi
216 GPa31.3 Msi

Poisson's Ratio

0.22
0.23

Flexural Strength

350 MPa50.8 ksi
700 MPa102 ksi

Shear Strength

330 MPa47.9 ksi
—

Fracture Toughness (K_IC)

4 MPa·√m3.6 ksi·√in
5.5 MPa·√m5 ksi·√in

Hardness, Vickers

1,650 HV
1,500 HV

Hardness, Knoop

1,440 HK
1,400 HK

Same in both: Tensile Strength (Ultimate) 260 MPa37.7 ksi · Compressive Strength 2,500 MPa363 ksi · Hardness, Mohs 9

Physical

Density and transition temperatures.

Density

3.9 g/cm³0.14 lb/in³
4.15 g/cm³0.15 lb/in³

Melting Point (Solidus)

2,050°C3,722 °F
1,870°C3,398 °F

Refractive Index

1.76
—

Porosity

0.1%
0.2%

Thermal

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

Thermal Conductivity

32 W/m·K18.5 BTU/hr·ft·°F
24 W/m·K13.9 BTU/hr·ft·°F

Specific Heat Capacity

880 J/kg·K0.21 BTU/lb·°F
780 J/kg·K0.19 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

7 µm/m·K3.9 µin/in·°F
8.3 µm/m·K4.6 µin/in·°F

Max Service Temperature (continuous)

1,700°C3,092 °F
1,500°C2,732 °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
1×10¹² Ω·m3.94×10¹⁹ µΩ·in

Dielectric Strength

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

Dielectric Constant (1 MHz)

9.8
12

Dissipation Factor (1 MHz)

2×10⁻⁴
0.001

Volume Resistivity

1×10¹⁵ Ω·cm
1×10¹⁴ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

95 / 100
92 / 100

Manufacturability

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

Polishability

88 / 100
90 / 100

Sintering / Firing Temperature

1,650°C3,002 °F
1,600°C2,912 °F

Same in both: Machinability 5 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

52 MJ/kg22,356 BTU/lb
80 MJ/kg34,394 BTU/lb

Embodied Carbon (primary production)

3 kg CO₂/kg
7 kg CO₂/kg

Typical Recycled Content

0%
1%

Same in both: Embodied Water 200 L/kg24 gal/lb

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

67 kN·m/kg
63 kN·m/kg

Specific Stiffness (E / density)

95.4 MN·m/kg
84.3 MN·m/kg

Thermal Diffusivity

9.3 mm²/s
7.4 mm²/s

Thermal Shock Resistance Index

3
2

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 99.5

Manufacturing and finishing

CapabilityAlumina 99.5ZTA
Default condition——
Relative cost$$$$ High$$$$ High
Min. machined wall——
Best machined surface——

Alumina 99.5 vs ZTA — frequently asked

What is the difference between Alumina 99.5 and ZTA?

Alumina 99.5 and ZTA are both ceramic grades. Alumina 99.5 is harder — 1,650 HV against 1,500 HV for ZTA — which matters for wear surfaces and threads. Alumina 99.5 is lighter (3.9 g/cm³ vs 4.15 g/cm³ for ZTA) and Alumina 99.5 is stiffer (372 GPa vs 350 GPa).

Which is cheaper, Alumina 99.5 or ZTA?

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 ZTA?

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

Ready to make it?

Upload a CAD file and FabDigit prices the part in Alumina 99.5 and ZTA 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.