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OK8/BK8 vs YG3 vs YG6 vs YG8

Benchmark · 4 materials

Side-by-side benchmark of 4 ceramic grades.

OK8/BK8 vs YG3 and 2 more: properties

OK8/BK8YG3YG6YG8

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

600 GPa87 Msi
650 GPa94.3 Msi
630 GPa91.4 Msi
600 GPa87 Msi

Shear Modulus

245 GPa35.5 Msi
268 GPa38.9 Msi
255 GPa37 Msi
245 GPa35.5 Msi

Bulk Modulus

370 GPa53.7 Msi
385 GPa55.8 Msi
375 GPa54.4 Msi
360 GPa52.2 Msi

Poisson's Ratio

0.22
0.21
0.22
0.22

Tensile Strength (Ultimate)

1,200 MPa174 ksi
1,100 MPa160 ksi
1,100 MPa160 ksi
1,200 MPa174 ksi

Elongation at Break

0%
0%
0.2%
0.1%

Compressive Strength

4,400 MPa638 ksi
6,000 MPa870 ksi
4,600 MPa667 ksi
4,500 MPa653 ksi

Flexural Strength

1,900 MPa276 ksi
1,200 MPa174 ksi
1,800 MPa261 ksi
2,000 MPa290 ksi

Shear Strength

1,100 MPa160 ksi
900 MPa131 ksi
1,200 MPa174 ksi
1,300 MPa189 ksi

Fracture Toughness (K_IC)

14.5 MPa·√m13.2 ksi·√in
8.5 MPa·√m7.7 ksi·√in
10 MPa·√m9.1 ksi·√in
14 MPa·√m12.7 ksi·√in

Hardness, Vickers

1,450 HV
1,580 HV
1,580 HV
1,350 HV

Hardness, Knoop

1,400 HK
1,500 HK
1,500 HK
1,400 HK

Same in both: Hardness, Mohs 9

Physical

Density and transition temperatures.

Density

14.6 g/cm³0.53 lb/in³
15.1 g/cm³0.55 lb/in³
14.9 g/cm³0.54 lb/in³
14.7 g/cm³0.53 lb/in³

Same in both: Melting Point (Solidus) 1,320°C2,408 °F · Porosity 0.02%

Thermal

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

Thermal Conductivity

75 W/m·K43.3 BTU/hr·ft·°F
88 W/m·K50.8 BTU/hr·ft·°F
80 W/m·K46.2 BTU/hr·ft·°F
75 W/m·K43.3 BTU/hr·ft·°F

Specific Heat Capacity

220 J/kg·K0.05 BTU/lb·°F
210 J/kg·K0.05 BTU/lb·°F
220 J/kg·K0.05 BTU/lb·°F
220 J/kg·K0.05 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

5.2 µm/m·K2.9 µin/in·°F
4.4 µm/m·K2.4 µin/in·°F
4.5 µm/m·K2.5 µin/in·°F
4.8 µm/m·K2.7 µin/in·°F

Max Service Temperature (continuous)

800°C1,472 °F
600°C1,112 °F
600°C1,112 °F
600°C1,112 °F

Min Service Temperature

-196°C-321 °F
-196°C-321 °F
-196°C-321 °F
-200°C-328 °F

Electrical

Conductivity and insulation.

Same in both: Electrical Resistivity 2×10⁻⁷ Ω·m7.87 µΩ·in · Volume Resistivity 2×10⁻⁵ Ω·cm

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

45 / 100
58 / 100
55 / 100
45 / 100

Manufacturability

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

Machinability

4 / 100
3 / 100
5 / 100
5 / 100

Polishability

92 / 100
92 / 100
90 / 100
90 / 100

Same in both: Sintering / Firing Temperature 1,420°C2,588 °F

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

420 MJ/kg180,568 BTU/lb
250 MJ/kg107,481 BTU/lb
330 MJ/kg141,875 BTU/lb
180 MJ/kg77,386 BTU/lb

Embodied Carbon (primary production)

30 kg CO₂/kg
20 kg CO₂/kg
24 kg CO₂/kg
12 kg CO₂/kg

Embodied Water

400 L/kg47.9 gal/lb
500 L/kg59.9 gal/lb
400 L/kg47.9 gal/lb
400 L/kg47.9 gal/lb

Same in both: Typical Recycled Content 30%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

82 kN·m/kg
73 kN·m/kg
74 kN·m/kg
82 kN·m/kg

Specific Stiffness (E / density)

41.1 MN·m/kg
43 MN·m/kg
42.3 MN·m/kg
40.8 MN·m/kg

Thermal Diffusivity

23.3 mm²/s
27.8 mm²/s
24.4 mm²/s
23.2 mm²/s

Thermal Shock Resistance Index

29
34
31
31

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

CapabilityOK8/BK8YG3YG6YG8
Default condition————
Relative cost$$$$ High$$$$ High$$$$ High$$$$ High
Min. machined wall————
Best machined surface————

Ready to make it?

Upload a CAD file and FabDigit prices the part in OK8/BK8 and YG3 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.