CsBr POLY-HP
Grade
POLY-HP = hot-pressed / forged polycrystalline CsBr blank
Use the hot-pressed or forged polycrystalline blank when higher mechanical strength and larger apertures are needed and slight scattering can be tolerated.
Values for the POLY-HP condition
Other CsBr tempers and conditions
CsBr is listed in 3 conditions; see the grade overview at CsBr.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
Europium-doped storage-phosphor / scintillator grade | Pick the europium-doped grade for columnar needle-structure photostimulable storage screens in X-ray imaging plates; it is not intended for infrared transmitting windows. | — | 6 | 1.5 | 19 HV | 0.9 W/m·K |
SC-IRDefault Bridgman-grown optical single crystal, IR window grade | Choose the Bridgman-grown single crystal for 0.2–40 µm far-infrared windows, prisms and beamsplitter substrates, and keep it in a dry environment during service. | — | 6 | 2 | 20 HV | 0.94 W/m·K |
POLY-HPThis page Hot-pressed / forged polycrystalline CsBr blank | Use the hot-pressed or forged polycrystalline blank when higher mechanical strength and larger apertures are needed and slight scattering can be tolerated. | — | 12 | 1 | 25 HV | 0.88 W/m·K |
What is CsBr POLY-HP?
CsBr POLY-HP is CsBr in the POLY-HP grade — use the hot-pressed or forged polycrystalline blank when higher mechanical strength and larger apertures are needed and slight scattering can be tolerated. CsBr POLY-HP has a tensile strength of 12 MPa (1.74 ksi), weaker than 92% of glass grades. Elongation at break is 1% and the elastic modulus is 16.5 GPa (2.39 Msi). CsBr POLY-HP has a density of 4.44 g/cm³ (0.16 lb/in³), heavier than 75% of glass grades. It melts at 636°C (1,177 °F). SC-IR is the default condition FabDigit quotes; POLY-HP is available on request or by drawing note.
Advantages
- Easy to machine — 50/100, better than 92% of glass grades
- Ductile — tolerates forming and impact — 1%, better than 80% of glass grades
Limitations
- Low fracture toughness — 0.15 MPa·√m (0.137 ksi·√in), worse than 97% of glass grades
- Low stiffness — 16.5 GPa (2.39 Msi), worse than 95% of glass grades
- Needs corrosion protection — 8/100, worse than 94% of glass grades
- Poor heat conductor — 0.88 W/m·K (0.508 BTU/hr·ft·°F), worse than 85% of glass grades
- Hard to polish — 55/100, worse than 85% of glass grades
CsBr POLY-HP properties
Typical room-temperature values for CsBr POLY-HP; 17 are specific to this condition. Other listed values are CsBr reference data and may not represent this condition. Bars are the position among glass grades.
Physical5
CsBr POLY-HP has a density of 4.44 g/cm³ (0.16 lb/in³), heavier than 75% of glass grades. It melts at 636°C (1,177 °F).
Mechanical13
CsBr POLY-HP has a tensile strength of 12 MPa (1.74 ksi), weaker than 92% of glass grades. Elongation at break is 1% and the elastic modulus is 16.5 GPa (2.39 Msi).
Thermal5
CsBr POLY-HP is rated for continuous service to 300°C (572 °F). It conducts heat at 0.88 W/m·K (0.508 BTU/hr·ft·°F), worse than 85% of glass grades. Thermal expansion is 47.9 µm/m·K (26.6 µin/in·°F).
Electrical3
CsBr POLY-HP has an electrical resistivity of 5×10⁹ Ω·m.
Chemical & Environmental2
Corrosion resistance is not recommended (8/100), worse than 94% of glass grades.
Manufacturability2
CsBr POLY-HP's machinability is fair (50/100, better than 92% of glass grades).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with CsBr POLY-HP
Is CsBr easy to machine?
Turn at low speed with sharp single-crystal diamond tools or cut dry with a wire saw; the crystal cleaves on {100}. Do not use water-based coolant, and dehumidify the machining enclosure.
Can CsBr be welded?
Not weldable; hold optics with mechanical retaining rings, dry-sealed O-rings or low-temperature optical cement.
Can CsBr be formed, bent or molded?
Blanks come from Bridgman–Stockbarger or Czochralski melt growth, or from hot-pressed/hot-forged polycrystalline billets. The material cannot be cold formed.
What surface finishes work on CsBr?
Polish with dry polishing powder carried in anhydrous ethanol or kerosene. Finished parts can be coated with KRS-5, Ge or polymer moisture barriers and must be stored in a desiccator at all times.
CsBr 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 |
|---|---|---|
| Csstoichiometric CsBr | 62.2 – 62.7 | 62.45 |
| Euonly in CsBr:Eu storage-phosphor variant | 0 – 0.5 | 0.1 |
| Br | ≥ 37.3 (balance) | — |
CsBr POLY-HP — frequently asked
What is CsBr POLY-HP used for?
CsBr POLY-HP is typically used for far-IR spectroscopy windows, IR prisms and FTIR components. In short: transmits to 40 µm; very soft, hygroscopic halide; doped storage-phosphor grade.
What is the tensile strength of CsBr POLY-HP?
CsBr POLY-HP has a typical tensile strength of 12 MPa (1.74 ksi) — weaker than 92% of glass grades. Strength varies by condition: see the 3 listed tempers.
Is CsBr POLY-HP easy to machine?
Reasonably — machinability is rated fair (50/100, better than 92% of glass grades). Turn at low speed with sharp single-crystal diamond tools or cut dry with a wire saw; the crystal cleaves on {100}. Do not use water-based coolant, and dehumidify the machining enclosure.
Can CsBr POLY-HP be welded?
Not weldable; hold optics with mechanical retaining rings, dry-sealed O-rings or low-temperature optical cement.
What surface finishes work on CsBr POLY-HP?
Polish with dry polishing powder carried in anhydrous ethanol or kerosene. Finished parts can be coated with KRS-5, Ge or polymer moisture barriers and must be stored in a desiccator at all times.
Can CsBr POLY-HP be formed, bent or molded?
Blanks come from Bridgman–Stockbarger or Czochralski melt growth, or from hot-pressed/hot-forged polycrystalline billets. The material cannot be cold formed.
What is the maximum service temperature of CsBr POLY-HP?
CsBr POLY-HP is rated for continuous use to about 300°C (572 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Handbook of Optical Materials — CRC Press (Weber) (2003)
- CRC Handbook of Chemistry and Physics — CRC Press (2020)
- CsBr IR window / crystal datasheet — Korth Kristalle GmbH (2022)
- Refractive index and dispersion of alkali halides — J. Phys. Chem. Ref. Data (1976)
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.