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BaF2 VUV

Grade

VUV = 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.

High cost $$$$

Values for the VUV 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 datasheetBest forYield MPaTensile MPaElong. %HardnessConductivity
VUVThis page
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.—27075 HV12 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.—27075 HV12 W/m·K
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 VUV?

BaF2 VUV is BaF2 in the VUV grade — 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. BaF2 VUV has a tensile strength of 27 MPa (3.9 ksi), weaker than 83% of glass grades. The elastic modulus is 53 GPa (7.69 Msi). BaF2 VUV has a density of 4.89 g/cm³ (0.177 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

Limitations

  • Low fracture toughness — 0.27 MPa·√m (0.246 ksi·√in), worse than 90% of glass grades
  • Needs corrosion protection — 28/100, worse than 90% of glass grades
  • Heavy — 4.89 g/cm³ (0.177 lb/in³), worse than 86% of glass grades
  • Low stiffness — 53 GPa (7.69 Msi), worse than 81% of glass grades
  • Hard to polish — 70/100, worse than 76% of glass grades

BaF2 VUV properties

Typical room-temperature values for BaF2 VUV; 14 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 VUV has a density of 4.89 g/cm³ (0.177 lb/in³), heavier than 86% of glass grades. It melts at 1,368°C (2,494 °F).

Density4.89 g/cm³0.18 lb/in³
Melting Point (Solidus)1,368°C2,494 °F
Refractive Index1.51
Light Transmission90%
Porosity0%

Mechanical10

BaF2 VUV has a tensile strength of 27 MPa (3.9 ksi), weaker than 83% of glass grades. The elastic modulus is 53 GPa (7.69 Msi).

Elastic (Young's) Modulus53 GPa7.7 Msi
Shear Modulus25.4 GPa3.7 Msi
Bulk Modulus56 GPa8.2 Msi
Poisson's Ratio0.34
Tensile Strength (Ultimate)27 MPa3.9 ksi
Flexural Strength27 MPa3.9 ksi
Fracture Toughness (K_IC)0.27 MPa·√m0.25 ksi·√in
Hardness, Vickers75 HV
Hardness, Knoop82 HK
Hardness, Mohs3

Thermal5

BaF2 VUV 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).

Thermal Conductivity11.7 W/m·K6.8 BTU/hr·ft·°F
Specific Heat Capacity410 J/kg·K0.1 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)18.1 µm/m·K10.1 µin/in·°F
Max Service Temperature (continuous)500°C932 °F
Min Service Temperature-200°C-328 °F

Electrical3

BaF2 VUV has an electrical resistivity of 1×10¹⁰ Ω·m.

Electrical Resistivity1×10¹⁰ Ω·m3.94×10¹⁷ µΩ·in
Dielectric Constant (1 MHz)7.33
Volume Resistivity1×10¹² Ω·cm

Chemical & Environmental2

Corrosion resistance is poor (28/100), worse than 90% of glass grades.

Corrosion ResistancePoor28/100
Chemical Resistance Summary—

Manufacturability2

BaF2 VUV's machinability is poor (30/100, better than 71% of glass grades).

MachinabilityPoor30/100
PolishabilityVery good70/100

Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.

Working with BaF2 VUV

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.

ElementSpec limit (wt %)Nominal
Bastoichiometric BaF2, M = 175.32 g/mol78 – 78.678.33
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 VUV — frequently asked

What is BaF2 VUV used for?

BaF2 VUV 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 VUV?

BaF2 VUV has a typical tensile strength of 27 MPa (3.9 ksi) — weaker than 83% of glass grades. Strength varies by condition: see the 3 listed tempers.

Is BaF2 VUV easy to machine?

Not especially — machinability is rated poor (30/100, better than 71% 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 VUV 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 VUV?

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 VUV 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 VUV?

BaF2 VUV 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

  1. CRC Handbook of Chemistry and Physics, 104th ed. — CRC Press (2023)
  2. Handbook of Optical Materials — CRC Press (M. J. Weber) (2003)
  3. Barium Fluoride (BaF2) crystal data sheet — Korth Kristalle GmbH (2022)
  4. BaF2 optical window material properties — Crystran Ltd. (2023)
  5. 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.