BaF2 POLY
Grade
POLY = hot-pressed / hot-forged polycrystalline BaF2
Choose the hot-pressed or hot-forged fine-grained polycrystal for large-aperture IR windows needing better strength and thermal-shock resistance; short-wave scatter rises and deep-UV use is excluded.
Values for the POLY condition
Other BaF2 tempers and conditions
BaF2 is listed in 3 conditions; see the grade overview at BaF2.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Vacuum-UV / oxygen-free high-purity single crystal | Pick the crystal grown in an anhydrous fluorinating atmosphere, with very low oxygen and hydroxyl content, for 150–200 nm deep-UV windows and excimer-laser optics. | — | 27 | 0 | 75 HV | 12 W/m·K |
Scintillation-grade single crystal | Use the scintillation grade when high-count-rate calorimetry or TOF detection needs the 220 nm fast 0.6 ns component and low self-absorption; crystal size and uniformity demands are high. | — | 27 | 0 | 75 HV | 12 W/m·K |
POLYThis page Hot-pressed / hot-forged polycrystalline BaF2 | Choose the hot-pressed or hot-forged fine-grained polycrystal for large-aperture IR windows needing better strength and thermal-shock resistance; short-wave scatter rises and deep-UV use is excluded. | — | 40 | — | — | — |
What is BaF2 POLY?
BaF2 POLY is BaF2 in the POLY grade — choose the hot-pressed or hot-forged fine-grained polycrystal for large-aperture IR windows needing better strength and thermal-shock resistance; short-wave scatter rises and deep-UV use is excluded. BaF2 POLY has a tensile strength of 40 MPa (5.8 ksi), weaker than 65% of glass grades. The elastic modulus is 53 GPa (7.69 Msi). BaF2 POLY has a density of 4.86 g/cm³ (0.176 lb/in³), heavier than 86% of glass grades. It melts at 1,368°C (2,494 °F).
Advantages
- Conducts heat well — 11.7 W/m·K (6.76 BTU/hr·ft·°F), better than 83% of glass grades
- Easy to machine — 35/100, better than 77% of glass grades
Limitations
- Needs corrosion protection — 30/100, worse than 90% of glass grades
- Heavy — 4.86 g/cm³ (0.176 lb/in³), worse than 86% of glass grades
- Hard to polish — 55/100, worse than 85% of glass grades
- Low stiffness — 53 GPa (7.69 Msi), worse than 81% of glass grades
- Low fracture toughness — 0.4 MPa·√m (0.364 ksi·√in), worse than 78% of glass grades
BaF2 POLY properties
Typical room-temperature values for BaF2 POLY; 10 are specific to this condition. Other listed values are BaF2 reference data and may not represent this condition. Bars are the position among glass grades.
Physical5
BaF2 POLY has a density of 4.86 g/cm³ (0.176 lb/in³), heavier than 86% of glass grades. It melts at 1,368°C (2,494 °F).
Mechanical10
BaF2 POLY has a tensile strength of 40 MPa (5.8 ksi), weaker than 65% of glass grades. The elastic modulus is 53 GPa (7.69 Msi).
Thermal5
BaF2 POLY is rated for continuous service to 500°C (932 °F). It conducts heat at 11.7 W/m·K (6.76 BTU/hr·ft·°F), better than 83% of glass grades. Thermal expansion is 18.1 µm/m·K (10.1 µin/in·°F).
Electrical3
BaF2 POLY has an electrical resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental2
Corrosion resistance is poor (30/100), worse than 90% of glass grades.
Manufacturability2
BaF2 POLY's machinability is fair (35/100, better than 77% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with BaF2 POLY
Is BaF2 easy to machine?
Cut and grind at low speed with diamond tooling and diamond slurry; single-point diamond turning is possible. Because the (111) plane cleaves easily, use light clamping force and water-free coolant such as kerosene or mineral oil.
Can BaF2 be welded?
Not weldable; optical elements are optically contacted, bonded with low-stress adhesive, or held in metal cells with compliant retaining rings.
Can BaF2 be formed, bent or molded?
Single crystals are grown from the melt by Bridgman–Stockbarger or crucible-lowering under a scavenger atmosphere (PbF2 or CF4). Polycrystalline parts can be hot-pressed or hot-forged at 800–1000 °C.
What surface finishes work on BaF2?
Pitch or polyurethane laps with anhydrous slurry reach λ/10 figure and 20-10 scratch-dig; AR and DLC coatings can be applied. Store finished parts dry to prevent moisture attack.
BaF2 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 |
|---|---|---|
| Bastoichiometric BaF2, M = 175.32 g/mol | 78 – 78.6 | 78.33 |
| OVUV grade requires O/OH impurities <10-50 ppm | ≤ 0.01 | — |
| Pb+Sr+Ca+rare earthtotal metal impurities, optical grade typically <500 ppm | ≤ 0.05 | — |
| F | ≥ 21.4 (balance) | — |
BaF2 POLY — frequently asked
What is BaF2 POLY used for?
BaF2 POLY is typically used for IR windows and lenses, UV spectroscopy optics, scintillation detectors and FTIR components. In short: 150 nm to 12.5 µm transmission; fast scintillation crystal; low refractive index fluoride.
What is the tensile strength of BaF2 POLY?
BaF2 POLY has a typical tensile strength of 40 MPa (5.8 ksi) — weaker than 65% of glass grades. Strength varies by condition: see the 3 listed tempers.
Is BaF2 POLY easy to machine?
Not especially — machinability is rated fair (35/100, better than 77% of glass grades). Cut and grind at low speed with diamond tooling and diamond slurry; single-point diamond turning is possible. Because the (111) plane cleaves easily, use light clamping force and water-free coolant such as kerosene or mineral oil.
Can BaF2 POLY be welded?
Not weldable; optical elements are optically contacted, bonded with low-stress adhesive, or held in metal cells with compliant retaining rings.
What surface finishes work on BaF2 POLY?
Pitch or polyurethane laps with anhydrous slurry reach λ/10 figure and 20-10 scratch-dig; AR and DLC coatings can be applied. Store finished parts dry to prevent moisture attack.
Can BaF2 POLY be formed, bent or molded?
Single crystals are grown from the melt by Bridgman–Stockbarger or crucible-lowering under a scavenger atmosphere (PbF2 or CF4). Polycrystalline parts can be hot-pressed or hot-forged at 800–1000 °C.
What is the maximum service temperature of BaF2 POLY?
BaF2 POLY 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.
Sources
- CRC Handbook of Chemistry and Physics, 104th ed. — CRC Press (2023)
- Handbook of Optical Materials — CRC Press (M. J. Weber) (2003)
- Barium Fluoride (BaF2) crystal data sheet — Korth Kristalle GmbH (2022)
- BaF2 optical window material properties — Crystran Ltd. (2023)
- 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. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.