N-LaK9
N-LaK9 is a lanthanum crown optical glass that combines a high refractive index with low dispersion, part of the LaK group of the standard optical glass catalogue.
Reference datasheet — N-LaK9 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.
N-LaK9 tempers and conditions
N-LaK9 is supplied in one standard condition, HT.
Supply forms, finishes and certifications
Ways N-LaK9 is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
FADefault | Fine annealed block/strip, standard index tolerance | Surface finish |
PA | Precision (fine) annealed, tight index/homogeneity and low stress… | Surface finish |
What is N-LaK9?
N-LaK9 is a lanthanum crown optical glass that combines a high refractive index with low dispersion, part of the LaK group of the standard optical glass catalogue. It is used for positive elements in high-performance imaging optics and is supplied as strip and pressed blanks in fine-annealed (FA), precision-annealed (PA) and HT variants. Service temperature is limited to 500 °C and Tg is about 640 °C, too high for standard low-Tg precision glass moulding. The polished surface is stain-sensitive, and N-BK7 is the usual fallback where index requirements allow. N-LaK9 has a density of 3.51 g/cm³ (0.127 lb/in³), heavier than 67% of glass grades. N-LaK9 has a tensile strength of 55 MPa (7.98 ksi), stronger than 71% of glass grades. The elastic modulus is 110 GPa (16 Msi).
What is N-LaK9 used for?
- camera lenses
- microscope objectives
- telescope optics
Advantages
- Stiff — 110 GPa (16 Msi), better than 83% of glass grades
Limitations
- Poor heat conductor — 0.9 W/m·K (0.52 BTU/hr·ft·°F), worse than 84% of glass grades
N-LaK9 properties
Typical room-temperature values; bars are the position among glass grades.
Physical4
N-LaK9 has a density of 3.51 g/cm³ (0.127 lb/in³), heavier than 67% of glass grades.
Mechanical11
N-LaK9 has a tensile strength of 55 MPa (7.98 ksi), stronger than 71% of glass grades. The elastic modulus is 110 GPa (16 Msi).
Thermal5
N-LaK9 is rated for continuous service to 500°C (932 °F). It conducts heat at 0.9 W/m·K (0.52 BTU/hr·ft·°F), worse than 84% of glass grades. Thermal expansion is 6.3 µm/m·K (3.5 µin/in·°F).
Electrical2
Chemical & Environmental2
Corrosion resistance is good (62/100), worse than 65% of glass grades.
Sustainability4
Producing a kilogram of N-LaK9 takes about 60 MJ of energy and emits 4.5 kg of CO₂ — more than 58% of glass grades. Typical recycled content is 20%.
Manufacturability2
N-LaK9's machinability is not recommended (12/100, worse than 68% 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-LaK9 is highlighted; hover a dot for its name, or open the interactive family chart.
Working with N-LaK9
Is N-LaK9 easy to machine?
No conventional machining — diamond core drilling, curve generating, loose-abrasive lapping then CeO2 polishing; grinds faster than N-BK7 but chips more at edges.
Can N-LaK9 be welded?
Not weldable; joining is by optical contact, UV/epoxy cementing or low-stress mounting.
Can N-LaK9 be formed, bent or molded?
Hot forming by reheat pressing of gobs above ~700 °C; Tg ≈ 640 °C is too high for standard low-Tg precision glass molding, and slow fine annealing is mandatory to control index and birefringence.
N-LaK9 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 |
|---|---|---|
| La2O3Typical of the lead-free lanthanum-borate crown family; exact batch is proprietary to the melter. | 25 – 45 | 35 |
| B2O3Network former, approximate family value | 15 – 30 | 22 |
| SiO2Approximate family value | 3 – 15 | 8 |
| ZnOApproximate family value | 3 – 15 | 8 |
| ZrO2Index/chemical-durability booster, approximate | 2 – 8 | 5 |
| CaO + BaO + other modifiersN-series is lead- and arsenic-free | balance |
What surface finishes work on N-LaK9?
Polished surfaces should be AR-coated promptly; the La-crown surface is stain-sensitive, so avoid alkaline cleaners and long humid storage.
How much does N-LaK9 cost?
N-LaK9 is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
N-LaK9 — frequently asked
What is N-LaK9 used for?
N-LaK9 is typically used for camera lenses, microscope objectives and telescope optics. In short: high index, low dispersion; grinds faster than N-BK7.
What is the tensile strength of N-LaK9?
N-LaK9 has a typical tensile strength of 55 MPa (7.98 ksi) — stronger than 71% of glass grades.
Is N-LaK9 easy to machine?
Not especially — machinability is rated not recommended (12/100, worse than 68% of glass grades). No conventional machining — diamond core drilling, curve generating, loose-abrasive lapping then CeO2 polishing; grinds faster than N-BK7 but chips more at edges.
Can N-LaK9 be welded?
Not weldable; joining is by optical contact, UV/epoxy cementing or low-stress mounting.
What surface finishes work on N-LaK9?
Polished surfaces should be AR-coated promptly; the La-crown surface is stain-sensitive, so avoid alkaline cleaners and long humid storage.
Can N-LaK9 be formed, bent or molded?
Hot forming by reheat pressing of gobs above ~700 °C; Tg ≈ 640 °C is too high for standard low-Tg precision glass molding, and slow fine annealing is mandatory to control index and birefringence.
What is the maximum service temperature of N-LaK9?
N-LaK9 is rated for continuous use to about 500°C (932 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does N-LaK9 cost?
N-LaK9 is a high-cost glass ($$$$), 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
- N-LaK9 optical glass datasheet / Optical Glass Data Sheets — SCHOTT AG (2023)
- TIE-19/TIE-33 Technical Information (stress birefringence, annealing) — SCHOTT AG (2020)
- ASM 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.