Сульфид цинка ZnS

МакроОптика produces lenses, windows, prisms, wedges, ball lenses, cylindrical lenses and others optical components according to customers’ specifications and drawings out of crystals zinc sulfide; ZnS.

ZnS FLIR is used for IR windows and lenses in the thermal band (8 to 14 μm) as a tough front optic in thermal imaging systems, particularly those subjected to harsh environments.

ZnS Multispectral (water-clear) is used for IR windows and lenses in the thermal band (8 to 14 μm) where maximum transmission and lowest absorption is required. Also selected for use where visible alignment is an advantage.

Zinc Sulphide is produced by synthesis from Zinc vapour and H2S gas, forming as sheets on Graphite susceptors. Zinc Sulphide is microcrystalline in structure, the grain size being controlled to produce maximum strength. Forward Looking Infra-Red (FLIR) grade, which is pale yellow and translucent in the visible, is used as deposited without further treatment. Multispectral grade is then Hot Isostatically Pressed (HIP) to improve the mid IR transmission and produce the visibly clear form; It is stronger than multispectral grade. Single crystal ZnS is available, but is not common.

ZnS oxidises significantly at 300°C, exhibits plastic deformation at about 500°C and dissociates about 700°C. For safety, Zinc Sulphide windows should not be used above 250°C in normal atmosphere.

Product Data

Transmission Range 1.0 to 13 Ојm
Refractive Index 2.192 at 10.6 Ојm
Reflection Loss 24.6% at 10.6 Ојm (2 surfaces)
Absorption Coefficient 0.02 cm-1 at 3.8 Ојm
Reststrahlen Peak 30.5 Ојm
dn/dT +43 x 10-6/В°C at 3.39 Ојm
dn/dОј 0: n/a
Density 4.08 g/cc
Melting Point 1827В°C (See notes below)
Thermal Conductivity 16.7 W m-1 K-1 at 296K
Thermal Expansion 6.6 x 10-6 /В°C at 273K
Hardness Knoop 160 with 50g indenter
Specific Heat Capacity 469 J Kg-1 K-1
Dielectric Constant n/a
Youngs Modulus (E) 74.5 GPa
Shear Modulus (G) n/a
Bulk Modulus (K) n/a
Elastic Coefficients Noy Available
Apparent Elastic Limit 103.4 MPa (15,000 psi)
Poisson Ratio 0.29
Solubility 65 x 10-6 g/100g water
Molecular Weight 97.43
Class/Structure Polycrystalline cubic, ZnS, F43m

Transmittance

Refractive Index

No = Ordinary Ray

µm No µm No µm No
0.42 2.516 0.46 2.458 0.50 2.419
0.54 2.391 0.58 2.371 0.62 2.355
0.66 2.342 0.70 2.332 0.74 2.323
0.78 2.316 0.82 2.31 0.86 2.305
0.90 2.301 0.94 2.297 0.98 2.294
1.00 2.292 1.40 2.275 1.80 2.267
2.20 2.263 2.60 2.26 3.00 2.257
3.40 2.255 3.80 2.253 4.20 2.251
4.60 2.248 5.00 2.246 5.40 2.244
5.80 2.241 6.20 2.238 6.60 2.235
7.00 2.232 7.40 2.228 7.80 2.225
8.20 2.221 8.60 2.217 9.00 2.212
9.40 2.208 9.80 2.203 10.2 2.198
10.6 2.192 11.0 2.186 11.4 2.18
11.8 2.173 12.2 2.167 12.6 2.159
13.0 2.152 13.4 2.143 13.8 2.135
14.2 2.126 14.6 2.116 15.0 2.106
15.4 2.095 15.8 2.084 16.2 2.072
16.6 2.059 17.0 2.045 17.4 2.03
17.8 2.015 18.2 1.998