N-F2
N-F2 is a moderate-index, high-dispersion flint glass from the lead-free N-series optical catalogue, with a density of 2.65 g/cm³ and a glass transition near 438 °C.
Reference datasheet — N-F2 is not in the instant-quote catalog. Upload your part and an engineer will quote it in this grade or suggest the closest stocked equivalent.
What is N-F2?
N-F2 is a moderate-index, high-dispersion flint glass from the lead-free N-series optical catalogue, with a density of 2.65 g/cm³ and a glass transition near 438 °C. It is the classic negative element of achromatic doublets and is supplied as annealed blocks, pressed blanks and gobs (FA, PA and PB conditions) for lens and prism shops. It is softer than crown glass, so generous stock removal is needed to clear subsurface damage before polishing, and it cannot be cold formed or welded. N-K5 is the usual crown partner in the same doublet. N-F2 has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 52% of glass grades. N-F2 has a tensile strength of 45 MPa (6.53 ksi), weaker than 56% of glass grades. Elongation at break is 0% and the elastic modulus is 57 GPa (8.27 Msi).
What is N-F2 used for?
- Achromatic doublets
- Microscope optics
- Telescope objectives
Limitations
- Poor heat conductor — 0.78 W/m·K (0.451 BTU/hr·ft·°F), worse than 90% of glass grades
- Low stiffness — 57 GPa (8.27 Msi), worse than 78% of glass grades
N-F2 properties
Typical room-temperature values; bars are the position among glass grades.
Physical4
N-F2 has a density of 2.65 g/cm³ (0.0957 lb/in³), lighter than 52% of glass grades.
Mechanical12
N-F2 has a tensile strength of 45 MPa (6.53 ksi), weaker than 56% of glass grades. Elongation at break is 0% and the elastic modulus is 57 GPa (8.27 Msi).
Thermal5
N-F2 is rated for continuous service to 400°C (752 °F). It conducts heat at 0.78 W/m·K (0.451 BTU/hr·ft·°F), worse than 90% of glass grades. Thermal expansion is 8.2 µm/m·K (4.56 µin/in·°F).
Electrical2
N-F2 has an electrical resistivity of 1×10¹¹ Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (78/100), better than 53% of glass grades.
Sustainability4
Producing a kilogram of N-F2 takes about 45 MJ of energy and emits 2.9 kg of CO₂ — less than 58% of glass grades. Typical recycled content is 5%.
Manufacturability2
N-F2's machinability is poor (22/100, better than 59% of glass grades).
Common Calculations4
Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.
Strength versus weight in the glass family
Yield strength against density for every glass grade FabDigit runs. N-F2 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with N-F2
Is N-F2 easy to machine?
No conventional cutting — saw with diamond blades, then loose-abrasive or diamond-pellet grinding; softer than crown glass so remove subsurface damage generously before polish.
Can N-F2 be welded?
Not weldable; joined optically by UV or thermoset cement in doublets, or by optical contacting / low-temperature frit for special assemblies.
Can N-F2 be formed, bent or molded?
Hot-formed only at the glass plant (Tg ≈ 438 °C); pressed blanks must be re-annealed to recover index and remove stress — no cold forming.
N-F2 chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| TiO2Main high-dispersion oxide replacing PbO | 5 – 15 | 10 |
| ZnOapproximate | 3 – 12 | 7 |
| BaOapproximate | 0 – 10 | 4 |
| Na2O+K2Oalkali fluxes; drive the relatively high CTE | 8 – 20 | 14 |
| PbOLead- and arsenic-free by definition of the N- series | 0 | 0 |
| SiO2Exact batch is proprietary; values are typical of the lead-free N-flint (Ti/Zn/Ba silicate) family. | ≥ 40 (balance) |
What surface finishes work on N-F2?
Cerium-oxide pitch or polyurethane polishing to λ/10; supports standard MgF₂ / multilayer AR coatings, but keep coating bake temperatures well below Tg and protect surfaces from alkaline cleaners.
How much does N-F2 cost?
N-F2 is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
N-F2 — frequently asked
What is N-F2 used for?
N-F2 is typically used for achromatic doublets, microscope optics and telescope objectives. In short: standard achromat flint; moderate index, high dispersion; softer than crown glass.
What is the tensile strength of N-F2?
N-F2 has a typical tensile strength of 45 MPa (6.53 ksi) — weaker than 56% of glass grades.
Is N-F2 easy to machine?
Not especially — machinability is rated poor (22/100, better than 59% of glass grades). No conventional cutting — saw with diamond blades, then loose-abrasive or diamond-pellet grinding; softer than crown glass so remove subsurface damage generously before polish.
Can N-F2 be welded?
Not weldable; joined optically by UV or thermoset cement in doublets, or by optical contacting / low-temperature frit for special assemblies.
What surface finishes work on N-F2?
Cerium-oxide pitch or polyurethane polishing to λ/10; supports standard MgF₂ / multilayer AR coatings, but keep coating bake temperatures well below Tg and protect surfaces from alkaline cleaners.
Can N-F2 be formed, bent or molded?
Hot-formed only at the glass plant (Tg ≈ 438 °C); pressed blanks must be re-annealed to recover index and remove stress — no cold forming.
What is the maximum service temperature of N-F2?
N-F2 is rated for continuous use to about 400°C (752 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does N-F2 cost?
N-F2 is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
Sources
- Optical Glass Data Sheets — N-F2 — SCHOTT AG (2023)
- TIE-19/TIE-29 Technical Information (temperature coefficients, mechanical properties of optical glass) — SCHOTT AG (2016)
- Engineered Materials Handbook Vol. 4: Ceramics and Glasses — ASM International (1991)
Property data is compiled from published supplier and standards handbooks and normalised for comparison; hardness values on non-Brinell scales are converted approximately for charting only. Manufacturability limits are FabDigit quote-engine defaults and may be relaxed by engineering review. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.