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BaF2 vs N-BK7

Glass · grade comparison

BaF2 and N-BK7 are both glass grades. N-BK7 is the stronger of the two: tensile strength 50 MPa (7.25 ksi) against 27 MPa (3.9 ksi) for BaF2, about 86% more. N-BK7 is harder — 610 HV against 75 HV for BaF2 — which matters for wear surfaces and threads. N-BK7 is lighter (2.51 g/cm³ vs 4.89 g/cm³ for BaF2) and N-BK7 is stiffer (82 GPa vs 53 GPa). On the shop floor, BaF2 machines more easily (30 vs 18 out of 100) and N-BK7 sits in a lower cost tier (standard, $$) than BaF2 (high, $$$$).

BaF2Choose it when the part is machined in volume.

N-BK7Choose it when strength drives the design, or when surface hardness matters.

BaF2 vs N-BK7: properties

BaF2N-BK7

Mechanical

Strength, stiffness, ductility and hardness at room temperature.

Elastic (Young's) Modulus

53 GPa7.7 Msi
82 GPa11.9 Msi

Shear Modulus

25.4 GPa3.7 Msi
34 GPa4.9 Msi

Bulk Modulus

56 GPa8.2 Msi
47 GPa6.7 Msi

Poisson's Ratio

0.34
0.21

Tensile Strength (Ultimate)

27 MPa3.9 ksi
50 MPa7.3 ksi

Flexural Strength

27 MPa3.9 ksi
65 MPa9.4 ksi

Fracture Toughness (K_IC)

0.27 MPa·√m0.25 ksi·√in
0.85 MPa·√m0.77 ksi·√in

Hardness, Vickers

75 HV
610 HV

Hardness, Knoop

82 HK
610 HK

Hardness, Mohs

3
6

Elongation at Break

—
0%

Compressive Strength

—
1,000 MPa145 ksi

Shear Strength

—
40 MPa5.8 ksi

Physical

Density and transition temperatures.

Density

4.89 g/cm³0.18 lb/in³
2.51 g/cm³0.09 lb/in³

Melting Point (Solidus)

1,368°C2,494 °F
—

Refractive Index

1.474
1.517

Same in both: Light Transmission 92% · Porosity 0%

Thermal

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

Thermal Conductivity

11.7 W/m·K6.8 BTU/hr·ft·°F
1.1 W/m·K0.64 BTU/hr·ft·°F

Specific Heat Capacity

410 J/kg·K0.1 BTU/lb·°F
858 J/kg·K0.2 BTU/lb·°F

Thermal Expansion (CTE, 20–100 °C)

18.1 µm/m·K10.1 µin/in·°F
7.1 µm/m·K3.9 µin/in·°F

Same in both: Max Service Temperature (continuous) 500°C932 °F · Min Service Temperature -200°C-328 °F

Electrical

Conductivity and insulation.

Electrical Resistivity

1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in
1×10¹² Ω·m3.94×10¹⁹ µΩ·in

Dielectric Constant (1 MHz)

7.33
7

Volume Resistivity

1×10¹² Ω·cm
1×10¹⁴ Ω·cm

Dielectric Strength

—
15 kV/mm381 V/mil

Chemical & Environmental

Corrosion and environmental resistance (0–100 scores).

Corrosion Resistance

30 / 100
78 / 100

Manufacturability

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

Machinability

30 / 100
18 / 100

Polishability

65 / 100
95 / 100

Sustainability

Primary-production footprint per kilogram.

Embodied Energy (primary production)

—
30 MJ/kg12,898 BTU/lb

Embodied Carbon (primary production)

—
2 kg CO₂/kg

Embodied Water

—
90 L/kg10.8 gal/lb

Typical Recycled Content

—
5%

Common Calculations

Ratios derived from the values above.

Specific Strength (UTS / density)

6 kN·m/kg
20 kN·m/kg

Specific Stiffness (E / density)

10.8 MN·m/kg
32.7 MN·m/kg

Thermal Diffusivity

5.8 mm²/s
0.5 mm²/s

Same in both: Thermal Shock Resistance Index 0

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 scaleN-BK7

Manufacturing and finishing

CapabilityBaF2N-BK7
Default condition—Annealed Glass
Relative cost$$$$ High$$ Standard
Min. machined wall——
Best machined surface——

BaF2 vs N-BK7 — frequently asked

Is N-BK7 stronger than BaF2?

Yes. N-BK7 has a typical tensile strength of 50 MPa (7.25 ksi) against 27 MPa (3.9 ksi) for BaF2 — about 86% more.

Which is cheaper, BaF2 or N-BK7?

N-BK7 is the lower-cost material: it sits in the standard tier ($$) while BaF2 is high ($$$$). Part price depends far more on geometry, tolerance and quantity than on raw stock — upload a CAD file for a live quote.

Which is easier to machine, BaF2 or N-BK7?

BaF2, by a small margin. Both rate poor for machinability — 30/100 against 18/100 for N-BK7.

Ready to make it?

Upload a CAD file and FabDigit prices the part in BaF2 and N-BK7 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.