NaCl HF-POLY
Grade
HF-POLY = hot-forged / press-forged polycrystalline NaCl
Use the fine-grained hot-forged polycrystal for large-aperture CO2 laser windows needing higher strength and cleavage resistance; scatter is slightly higher and service temperature drops to 350 °C.
Values for the HF-POLY condition
Other NaCl tempers and conditions
NaCl is listed in 2 conditions; see the grade overview at NaCl.
- SC-IR
- HF-POLY
Compare all 2 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SC-IRDefault Czochralski/Kyropoulos grown single crystal, IR optical grade | Pick the Czochralski/Kyropoulos-grown single crystal for standard IR windows, prisms and liquid cells where highest transmission and lowest scatter matter; cleavage planes limit handling and machining. | — | 3 | — | 20 HV | 7 W/m·K |
HF-POLYThis page Hot-forged / press-forged polycrystalline NaCl | Use the fine-grained hot-forged polycrystal for large-aperture CO2 laser windows needing higher strength and cleavage resistance; scatter is slightly higher and service temperature drops to 350 °C. | — | — | — | — | — |
What is NaCl HF-POLY?
NaCl HF-POLY is NaCl in the HF-POLY grade — use the fine-grained hot-forged polycrystal for large-aperture CO2 laser windows needing higher strength and cleavage resistance; scatter is slightly higher and service temperature drops to 350 °C. NaCl HF-POLY has a tensile strength of 3 MPa (0.435 ksi), weaker than 98% of glass grades. The elastic modulus is 40 GPa (5.8 Msi). NaCl HF-POLY has a density of 2.17 g/cm³ (0.0782 lb/in³), lighter than 98% of glass grades. It melts at 801°C (1,474 °F). SC-IR is the default condition FabDigit quotes; HF-POLY is available on request or by drawing note.
Advantages
- Low embodied carbon — 1.2 kg CO₂/kg, better than 99% of glass grades
- Lightweight — 2.17 g/cm³ (0.0782 lb/in³), better than 98% of glass grades
- Easy to machine — 55/100, better than 93% of glass grades
Limitations
- Needs corrosion protection — 5/100, worse than 98% of glass grades
- Hard to polish — 45/100, worse than 92% of glass grades
- Low stiffness — 40 GPa (5.8 Msi), worse than 85% of glass grades
- Low fracture toughness — 0.5 MPa·√m (0.455 ksi·√in), worse than 76% of glass grades
NaCl HF-POLY properties
Typical room-temperature values for NaCl HF-POLY; 10 are specific to this condition. Other listed values are NaCl reference data and may not represent this condition. Bars are the position among glass grades.
Physical5
NaCl HF-POLY has a density of 2.17 g/cm³ (0.0782 lb/in³), lighter than 98% of glass grades. It melts at 801°C (1,474 °F).
Mechanical12
NaCl HF-POLY has a tensile strength of 3 MPa (0.435 ksi), weaker than 98% of glass grades. The elastic modulus is 40 GPa (5.8 Msi).
Thermal5
NaCl HF-POLY is rated for continuous service to 350°C (662 °F). It conducts heat at 6.5 W/m·K (3.76 BTU/hr·ft·°F), better than 74% of glass grades. Thermal expansion is 44 µm/m·K (24.4 µin/in·°F).
Electrical5
NaCl HF-POLY is an electrical insulator with a dielectric strength of 15 kV/mm (381 V/mil) and a resistivity of 1×10¹² Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (5/100), worse than 98% of glass grades.
Sustainability4
Producing a kilogram of NaCl HF-POLY takes about 20 MJ of energy and emits 1.2 kg of CO₂ — less than 92% of glass grades. Typical recycled content is 20%.
Manufacturability2
NaCl HF-POLY's machinability is good (55/100, better than 93% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with NaCl HF-POLY
Is NaCl easy to machine?
Single-point diamond turn or dry grind to shape, always in a low-humidity environment (<30 % RH). Use only anhydrous coolants and lubricants — mineral oil or dry cutting is usual, and isopropanol should be used with care.
Can NaCl be welded?
Not applicable. Bond optics with dry silicone or epoxy in a dry environment, and leave clearance in the mount for the high CTE.
Can NaCl be formed, bent or molded?
Large boules are grown from the melt by the Kyropoulos, Czochralski or Bridgman methods; blanks can also be hot forged at 400–600 °C into fine-grained polycrystalline material for higher strength.
What surface finishes work on NaCl?
Dry polish with an anhydrous polishing fluid or dry pad, then immediately apply a moisture-barrier/AR coating or store in a dry nitrogen cabinet. Fogged surfaces can be recovered by re-polishing dry.
NaCl 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 |
|---|---|---|
| Nastoichiometric | 39.2 – 39.4 | 39.34 |
| total metallic impuritiesoptical grade; K, Ca, Mg, Fe, Br typically <50 ppm each | ≤ 0.01 | 0.01 |
| Clstoichiometric | balance | — |
NaCl HF-POLY — frequently asked
What is NaCl HF-POLY used for?
NaCl HF-POLY is typically used for IR spectroscopy windows, disposable IR sample cells and IR prisms. In short: cheapest IR window crystal; highly hygroscopic; dry storage; transmits 0.2–16 µm.
What is the tensile strength of NaCl HF-POLY?
NaCl HF-POLY has a typical tensile strength of 3 MPa (0.435 ksi) — weaker than 98% of glass grades. Strength varies by condition: see the 2 listed tempers.
Is NaCl HF-POLY easy to machine?
Reasonably — machinability is rated good (55/100, better than 93% of glass grades). Single-point diamond turn or dry grind to shape, always in a low-humidity environment (<30 % RH). Use only anhydrous coolants and lubricants — mineral oil or dry cutting is usual, and isopropanol should be used with care.
Can NaCl HF-POLY be welded?
Not applicable. Bond optics with dry silicone or epoxy in a dry environment, and leave clearance in the mount for the high CTE.
What surface finishes work on NaCl HF-POLY?
Dry polish with an anhydrous polishing fluid or dry pad, then immediately apply a moisture-barrier/AR coating or store in a dry nitrogen cabinet. Fogged surfaces can be recovered by re-polishing dry.
Can NaCl HF-POLY be formed, bent or molded?
Large boules are grown from the melt by the Kyropoulos, Czochralski or Bridgman methods; blanks can also be hot forged at 400–600 °C into fine-grained polycrystalline material for higher strength.
What is the maximum service temperature of NaCl HF-POLY?
NaCl HF-POLY is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Sodium Chloride (NaCl) optical material datasheet — Crystran Ltd (2023)
- NaCl IR window and prism data — Korth Kristalle GmbH (2022)
- CRC Handbook of Chemistry and Physics, 102nd ed. — CRC Press (2021)
- Refractive index of NaCl (Li 1976 dispersion data) — J. Phys. Chem. Ref. Data / refractiveindex.info (1976)
- ASM Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- NaCl/KBr (2025)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.