AgBr
AgBr is a soft, plastic, non-hygroscopic silver halide crystal transmitting to about 35 µm, supplied as optical single crystal, extrusion-grade and hot-pressed polycrystal.
Reference datasheet — AgBr 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.
Values for the SC-OPT condition
AgBr tempers and conditions
AgBr is supplied in 3 conditions, soft to hard. SC-OPT is the default FabDigit quotes; the values on this page are for it.
Compare all 3 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
SC-OPTDefault Optical-grade single crystal | Choose for windows, ATR prisms and lenses where lowest scatter and best IR transmission are needed. | 20 | 40 | 1 W/m·K | ||
Hot-pressed / forged polycrystalline blank | Choose for large, low-cost windows and gaskets where slight scatter is acceptable. | 24 | 20 | 10 HV | 1 W/m·K | |
Extruded polycrystalline rod / IR fiber preform | Choose when the material must be cold-extruded into unclad far-IR fibres or flexible light guides. | 28 | 50 | 9 HV | 1 W/m·K |
What is AgBr?
AgBr is a soft, plastic, non-hygroscopic silver halide crystal transmitting to about 35 µm, supplied as optical single crystal, extrusion-grade and hot-pressed polycrystal. Room-temperature ductility (about 40% elongation at 20 MPa tensile strength) allows cold extrusion into far-IR fibre, and the moisture resistance suits humid and marine service where KBr or KCl fail. Limits are a 200 °C maximum service temperature, 1.1 W/m·K thermal conductivity, light sensitivity and high reflection loss from n≈2.25, which requires AR coating. AgCl is the nearest alternative with a shorter IR cutoff. AgBr has a density of 6.47 g/cm³ (0.234 lb/in³), heavier than 98% of glass grades. It melts at 432°C (810 °F). AgBr has a tensile strength of 20 MPa (2.9 ksi), weaker than 89% of glass grades. Elongation at break is 40% and the elastic modulus is 22 GPa (3.19 Msi).
What is AgBr used for?
- far-IR fiber optics
- IR windows in humid/marine settings
- radiometry components
Advantages
- Ductile — tolerates forming and impact — 40%, better than 100% of glass grades
Limitations
- Heavy — 6.47 g/cm³ (0.234 lb/in³), worse than 98% of glass grades
- Low stiffness — 22 GPa (3.19 Msi), worse than 92% of glass grades
- High embodied carbon — 70 kg CO₂/kg, worse than 90% of glass grades
- Limited service temperature — 200°C (392 °F), worse than 88% of glass grades
- Hard to polish — 55/100, worse than 85% of glass grades
AgBr properties
Typical room-temperature values for AgBr-SC-OPT; bars are the position among glass grades.
Physical5
AgBr has a density of 6.47 g/cm³ (0.234 lb/in³), heavier than 98% of glass grades. It melts at 432°C (810 °F).
Mechanical11
AgBr has a tensile strength of 20 MPa (2.9 ksi), weaker than 89% of glass grades. Elongation at break is 40% and the elastic modulus is 22 GPa (3.19 Msi).
Thermal5
AgBr is rated for continuous service to 200°C (392 °F). It conducts heat at 1.1 W/m·K (0.636 BTU/hr·ft·°F), worse than 68% of glass grades. Thermal expansion is 33 µm/m·K (18.3 µin/in·°F).
Electrical3
AgBr has an electrical resistivity of 1,000,000 Ω·m.
Chemical & Environmental2
Corrosion resistance is very good (72/100), worse than 53% of glass grades.
Sustainability4
Producing a kilogram of AgBr takes about 900 MJ of energy and emits 70 kg of CO₂ — more than 89% of glass grades. Typical recycled content is 40%.
Manufacturability2
AgBr's machinability is poor (30/100, better than 71% 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. AgBr is highlighted; hover a dot for its name, or open the interactive family chart.
Working with AgBr
Is AgBr easy to machine?
Very soft and prone to smearing on the tool — use single-point diamond turning or light-load diamond sawing. Cutting fluids must be free of ammonia and sulfides, and aluminium or copper fixtures must not be used.
Can AgBr be welded?
Not weldable; components are cold-welded by press or extrusion plastic deformation, or bonded with optical cement.
Can AgBr be formed, bent or molded?
Flows plastically at room temperature, so it can be cold extruded into IR fibre or hot pressed into window blanks. Forming temperature is typically 100–250 °C, with silver-plated or graphite dies.
AgBr 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 |
|---|---|---|
| Agstoichiometric AgBr, M = 187.77 g/mol | 57.2 – 57.7 | 57.45 |
| impuritiestypical 4N–5N raw salt; Cl, I, Fe, Cu, Pb controlled at ppm level | ≤ 0.05 | 0.01 |
| Br | ≥ 42.3 (balance) |
What surface finishes work on AgBr?
Wet polish with very fine diamond slurry in anhydrous or neutral media. Store polished parts away from light; AR coating is normally applied to offset the high reflection loss from n≈2.25.
How much does AgBr cost?
AgBr is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
AgBr — frequently asked
What is AgBr used for?
AgBr is typically used for far-IR fiber optics, IR windows in humid/marine settings and radiometry components. In short: transmits to 35 µm; non-hygroscopic silver halide; cold-extrudable into fibre.
What is the tensile strength of AgBr?
AgBr has a typical tensile strength of 20 MPa (2.9 ksi) — weaker than 89% of glass grades. Strength varies by condition: see the 3 listed tempers.
Is AgBr easy to machine?
Not especially — machinability is rated poor (30/100, better than 71% of glass grades). Very soft and prone to smearing on the tool — use single-point diamond turning or light-load diamond sawing. Cutting fluids must be free of ammonia and sulfides, and aluminium or copper fixtures must not be used.
Can AgBr be welded?
Not weldable; components are cold-welded by press or extrusion plastic deformation, or bonded with optical cement.
What surface finishes work on AgBr?
Wet polish with very fine diamond slurry in anhydrous or neutral media. Store polished parts away from light; AR coating is normally applied to offset the high reflection loss from n≈2.25.
Can AgBr be formed, bent or molded?
Flows plastically at room temperature, so it can be cold extruded into IR fibre or hot pressed into window blanks. Forming temperature is typically 100–250 °C, with silver-plated or graphite dies.
What is the maximum service temperature of AgBr?
AgBr is rated for continuous use to about 200°C (392 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does AgBr cost?
AgBr is a high-cost glass ($$$$), 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
- CRC Handbook of Chemistry and Physics — silver bromide physical data — CRC Press (2021)
- Handbook of Optical Constants of Solids (Palik) — AgBr — Academic Press (1998)
- Infrared window & ATR crystal material property tables (silver halides) — IR optics manufacturers (2023)
- Elastic constants of alkali/silver halides — Landolt-Börnstein (1992)
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.