FabDigit

Robax vs ZERODUR and 2 more: properties

RobaxZERODURMycalexPyroceram 9606

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

92 GPa13.3 Msi
90.3 GPa13.1 Msi
65 GPa9.4 Msi
120 GPa17.4 Msi

Shear Modulus

37 GPa5.4 Msi
36.3 GPa5.3 Msi
26 GPa3.8 Msi
48 GPa7 Msi

Bulk Modulus

59 GPa8.6 Msi
59 GPa8.5 Msi
43 GPa6.2 Msi
78 GPa11.3 Msi

Poisson's Ratio

0.24
0.24
0.25
0.25

Tensile Strength (Ultimate)

35 MPa5.1 ksi
30 MPa4.4 ksi
45 MPa6.5 ksi
120 MPa17.4 ksi

Elongation at Break

0%
0.1%
0%

Compressive Strength

500 MPa72.5 ksi
500 MPa72.5 ksi
345 MPa50 ksi
1,250 MPa181 ksi

Flexural Strength

60 MPa8.7 ksi
51 MPa7.4 ksi
105 MPa15.2 ksi
235 MPa34.1 ksi

Shear Strength

40 MPa5.8 ksi
90 MPa13.1 ksi
150 MPa21.8 ksi

Fracture Toughness (K_IC)

0.9 MPa·√m0.82 ksi·√in
0.9 MPa·√m0.82 ksi·√in
1.3 MPa·√m1.2 ksi·√in
2.2 MPa·√m2 ksi·√in

Hardness, Vickers

590 HV
620 HV
250 HV
700 HV

Hardness, Knoop

630 HK
620 HK
240 HK
698 HK

Hardness, Mohs

6.5
6.2
5
6.5

Physical

Density and transition temperatures.

Density

2.55 g/cm³0.09 lb/in³
2.53 g/cm³0.09 lb/in³
3.4 g/cm³0.12 lb/in³
2.6 g/cm³0.09 lb/in³

Refractive Index

1.54
1.542

Light Transmission

88%
88%
0%

Melting Point (Solidus)

1,350°C2,462 °F

Same in both: Porosity 0%

Thermal

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

Thermal Conductivity

1.6 W/m·K0.92 BTU/hr·ft·°F
1.5 W/m·K0.84 BTU/hr·ft·°F
0.7 W/m·K0.4 BTU/hr·ft·°F
3.6 W/m·K2.1 BTU/hr·ft·°F

Specific Heat Capacity

830 J/kg·K0.2 BTU/lb·°F
800 J/kg·K0.19 BTU/lb·°F
790 J/kg·K0.19 BTU/lb·°F
800 J/kg·K0.19 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

0.1 µm/m·K0.06 µin/in·°F
0 µm/m·K0 µin/in·°F
11 µm/m·K6.1 µin/in·°F
4.5 µm/m·K2.5 µin/in·°F

Max Service Temperature (continuous)

700°C1,292 °F
500°C932 °F
350°C662 °F
1,200°C2,192 °F

Min Service Temperature

-200°C-328 °F
-270°C-454 °F
-200°C-328 °F
-200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in

Dielectric Strength

25 kV/mm635 V/mil
20 kV/mm508 V/mil
15 kV/mm381 V/mil
16 kV/mm406 V/mil

Dielectric Constant (1 MHz)

7
7.4
9.2
5.6

Dissipation Factor (1 MHz)

0.003
0.0035
0.002
3×10⁻⁴

Volume Resistivity

1×10¹³ Ω·cm
1×10¹⁴ Ω·cm
1×10¹⁴ Ω·cm
1×10¹⁴ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

85 / 100
85 / 100
78 / 100
88 / 100

Manufacturability

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

Machinability

6 / 100
20 / 100
75 / 100
5 / 100

Polishability

88 / 100
96 / 100
45 / 100
70 / 100

Sintering / Firing Temperature

900°C1,652 °F
850°C1,562 °F
700°C1,292 °F
1,200°C2,192 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

30 MJ/kg12,898 BTU/lb
90 MJ/kg38,693 BTU/lb
32 MJ/kg13,758 BTU/lb
45 MJ/kg19,347 BTU/lb

Embodied Carbon (primary production)

2.2 kg CO₂/kg
6.5 kg CO₂/kg
2.2 kg CO₂/kg
3 kg CO₂/kg

Embodied Water

20 L/kg2.4 gal/lb
150 L/kg18 gal/lb
40 L/kg4.8 gal/lb
25 L/kg3 gal/lb

Typical Recycled Content

0%
0%
5%
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

14 kN·m/kg
12 kN·m/kg
13 kN·m/kg
46 kN·m/kg

Specific Stiffness (E / density)

36.1 MN·m/kg
35.7 MN·m/kg
19.1 MN·m/kg
46.2 MN·m/kg

Thermal Diffusivity

0.8 mm²/s
0.7 mm²/s
0.3 mm²/s
1.7 mm²/s

Strength versus weight

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

501002005002.533.5Density (g/cm³)Yield strength (MPa) — log scaleZERODURRobax

Manufacturing and finishing

CapabilityRobaxZERODURMycalexPyroceram 9606
Default conditionAnnealed GlassAnnealed Glass
Relative cost$$ Standard$$ Standard$$$$ High$$$$ High
Min. machined wall
Best machined surface

Ready to make it?

Upload a CAD file and FabDigit prices the part in Robax and ZERODUR 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.