ZnS
also Cleartran, Irtran-2
ZnS (Cleartran, Irtran-2) is a polycrystalline II-VI material deposited by CVD that transmits from the visible into the far IR, 0.37–14 µm; the multispectral Cleartran grade is HIP-treated for broadband clarity, and hot-pressed grades are also available.
Reference datasheet — ZnS 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.
ZnS tempers and conditions
ZnS is supplied in one standard condition, HP.
Supply forms, finishes and certifications
Ways ZnS is supplied — form, process route, surface or paperwork — without a datasheet of their own. The property values above apply.
| Option | What it is | Type |
|---|---|---|
CVDDefault | Standard chemical-vapour-deposited ZnS | Coating |
MS | Multispectral (HIPed) ZnS, Cleartran type | Coating |
What is ZnS?
ZnS (Cleartran, Irtran-2) is a polycrystalline II-VI material deposited by CVD that transmits from the visible into the far IR, 0.37–14 µm; the multispectral Cleartran grade is HIP-treated for broadband clarity, and hot-pressed grades are also available. Engineers select it for rugged domes and windows, with 74.5 GPa elastic modulus, 27.2 W/m·K thermal conductivity and service to about 350 °C. It is still soft and brittle, scratches readily and loses roughly 28 % to Fresnel reflection, so AR or hard-carbon coatings are effectively standard. ZnSe is preferred where low absorption at 10.6 µm governs. ZnS has a density of 4.09 g/cm³ (0.148 lb/in³), heavier than 73% of glass grades. It melts at 1,830°C (3,326 °F). The elastic modulus is 74.5 GPa (10.8 Msi).
What is ZnS used for?
- IR domes and windows
- multispectral optics
- missile seeker domes
- thermal imaging
Advantages
- Conducts heat well — 27.2 W/m·K (15.7 BTU/hr·ft·°F), better than 90% of glass grades
- Tough — resists crack growth — 1 MPa·√m (0.91 ksi·√in), better than 87% of glass grades
- Easy to machine — 45/100, better than 85% of glass grades
Limitations
- High embodied carbon — 30 kg CO₂/kg, worse than 82% of glass grades
ZnS properties
Typical room-temperature values; bars are the position among glass grades.
Physical5
ZnS has a density of 4.09 g/cm³ (0.148 lb/in³), heavier than 73% of glass grades. It melts at 1,830°C (3,326 °F).
Mechanical10
The elastic modulus is 74.5 GPa (10.8 Msi).
Thermal5
ZnS is rated for continuous service to 350°C (662 °F). It conducts heat at 27.2 W/m·K (15.7 BTU/hr·ft·°F), better than 90% of glass grades. Thermal expansion is 6.6 µm/m·K (3.67 µin/in·°F).
Electrical3
ZnS has an electrical resistivity of 1×10¹⁰ Ω·m.
Chemical & Environmental2
Corrosion resistance is good (55/100), worse than 74% of glass grades.
Sustainability4
Producing a kilogram of ZnS takes about 450 MJ of energy and emits 30 kg of CO₂ — more than 84% of glass grades. Typical recycled content is 0%.
Manufacturability3
ZnS's machinability is fair (45/100, better than 85% of glass grades).
Common Calculations2
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. ZnS is highlighted; hover a dot for its name, or open the interactive family chart.
Working with ZnS
Is ZnS easy to machine?
Soft and brittle — grind and lap with diamond, or single-point diamond turn to optical figure; use light loads and wet cutting to avoid chipping and to control toxic ZnS dust.
Can ZnS be welded?
Not weldable; joined only by optical contacting, epoxy/edge bonding or metal-to-glass style mounting in compliant retainers.
Can ZnS be formed, bent or molded?
Net shape is set by CVD deposition onto a mandrel (flat plates or domes), optionally followed by HIP for the multispectral grade; no plastic forming is possible.
ZnS 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 |
|---|---|---|
| Znstoichiometric ZnS | 66.8 – 67.5 | 67.1 |
| S | ≥ 32.5 (balance) |
What surface finishes work on ZnS?
Polishes to <20 Å rms with pitch/colloidal silica but scratches easily — almost always finished with AR/DLC or hard carbon coatings for durability and to cut the ~28 % Fresnel loss.
Equivalent designations
Standards and trade names that resolve to ZnS in FabDigit's catalog. Equivalence is nominal — check the exact specification when certification matters.
- Trade names
- CleartranIrtran-2
How much does ZnS cost?
ZnS is a high-cost glass ($$$$), pricier than about 78% of the materials FabDigit quotes. Part price depends far more on geometry, tolerance and quantity than on the raw stock — upload a CAD file for a live quote.
ZnS — frequently asked
What is ZnS used for?
ZnS is typically used for IR domes and windows, multispectral optics, missile seeker domes and thermal imaging. In short: rugged multispectral IR window; visible through far-IR transmission; tougher, cheaper than ZnSe.
Is ZnS easy to machine?
Reasonably — machinability is rated fair (45/100, better than 85% of glass grades). Soft and brittle — grind and lap with diamond, or single-point diamond turn to optical figure; use light loads and wet cutting to avoid chipping and to control toxic ZnS dust.
Can ZnS be welded?
Not weldable; joined only by optical contacting, epoxy/edge bonding or metal-to-glass style mounting in compliant retainers.
What surface finishes work on ZnS?
Polishes to <20 Å rms with pitch/colloidal silica but scratches easily — almost always finished with AR/DLC or hard carbon coatings for durability and to cut the ~28 % Fresnel loss.
Can ZnS be formed, bent or molded?
Net shape is set by CVD deposition onto a mandrel (flat plates or domes), optionally followed by HIP for the multispectral grade; no plastic forming is possible.
What is the maximum service temperature of ZnS?
ZnS is rated for continuous use to about 350°C (662 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
How much does ZnS cost?
ZnS is a high-cost glass ($$$$), 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
- CVD Zinc Sulfide and Multispectral ZnS optical material data — II-VI / Coherent (2022)
- Cleartran multispectral zinc sulfide — Dow / Rohm and Haas Advanced Materials (2008)
- Engineered Materials Handbook Vol.4: Ceramics and Glasses — ASM International (1991)
- Handbook of Optical Constants of Solids — Academic Press (1998)
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.