CVD ZINC SULFIDE®
Chemically
vapor deposited zinc sulfide (CVD ZINC SULFIDE®) is the low
cost alternative for infrared windows, domes and optical elements. With a
fracture strength double that of zinc selenide, and high hardness, zinc sulfide
has been used successfully in many military applications requiring mechanical
resistance to hostile environments. Missile domes and external windows for
military aircraft have been produced by Advanced Materials' CVD ZINC SULFIDE®
as the mechanical features of this material allow for high resistance to rain
and dust. Its low cost also makes it attractive for commercial applications.
Summary:
Description
Advanced Materials' CVD ZINC SULFIDE®
is chemically inert, non-hygroscopic, highly pure, theoretically dense and
easily machined. Like zinc selenide, zinc sulfide displays a high level of
index of refraction homogeneity and offers imaging uniformity across the 8-12
micron waveband. This material also transmits in the mid-wave IR region, but
with higher absorption and scatter as the wavenumber increases.
Available Forms
Custom diameters, rectangles, CNC-profiled blanks, generated
lens blanks, prisms, and near-net shape domes can be made to your specifications.
Sheet material is also available.
Evaporative Source Material
Advanced Materials' CVD ZINC SULFIDE® is also available as
an evaporative source material. It is supplied in specified lump sizes (2-20mm)
which to minimize surface contamination are hand selected to be free from
saw cut, abraded or polished edges.
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Transmission
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| Optical Properties: |
| 10% transmission limits (t=6mm) |
1.0 - 14µm |
| Index of refraction inhomogeneity (Dn/n) |
| - |
(ppm @ 10.6µm) |
<100 |
| Thermo-optic coefficient, dn/dT(298-358K) |
| |
(1/K @ 1.15µm) |
4.6 x 10-5 |
| (1/K @ 3.39µm) |
4.3 x 10-5 |
| (1/K @ 10.6µm) |
4.1 x 10-5 |
| Bulk absorption coefficient |
| |
(1/cm @ 10.6µm) |
2.0 x 10-1 |
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| Indices of Refraction
(n) |
| as a function of wavelength at room temperature (20°C) |
| Wavelength (µ) |
n |
Wavelength (µ) |
n |
| 0.42 |
2.516 |
7.00 |
2.232 |
| 0.46 |
2.458 |
7.40 |
2.228 |
| 0.50 |
2.419 |
7.80 |
2.225 |
| 0.54 |
2.391 |
8.20 |
2.221 |
| 0.58 |
2.371 |
8.60 |
2.217 |
| 0.62 |
2.355 |
9.00 |
2.212 |
| 0.66 |
2.342 |
9.40 |
2.208 |
| 0.70 |
2.332 |
9.80 |
2.203 |
| 0.74 |
2.323 |
10.20 |
2.198 |
| 0.78 |
2.316 |
10.60 |
2.192 |
| 0.82 |
2.310 |
11.00 |
2.186 |
| 0.86 |
2.305 |
11.40 |
2.180 |
| 0.90 |
2.301 |
11.80 |
2.173 |
| 0.94 |
2.297 |
12.20 |
2.167 |
| 0.98 |
2.294 |
12.60 |
2.159 |
| 1.00 |
2.292 |
13.00 |
2.152 |
| 1.40 |
2.275 |
13.40 |
2.143 |
| 1.80 |
2.267 |
13.80 |
2.135 |
| 2.20 |
2.263 |
14.20 |
2.126 |
| 2.60 |
2.260 |
14.60 |
2.116 |
| 3.00 |
2.257 |
15.00 |
2.106 |
| 3.40 |
2.255 |
15.40 |
2.095 |
| 3.80 |
2.253 |
15.80 |
2.084 |
| 4.20 |
2.251 |
16.20 |
2.072 |
| 4.60 |
2.248 |
16.60 |
2.059 |
| 5.00 |
2.246 |
17.00 |
2.045 |
| 5.40 |
2.244 |
17.40 |
2.030 |
| 5.80 |
2.241 |
17.80 |
2.015 |
| 6.20 |
2.238 |
18.20 |
1.998 |
| 6.60 |
2.235 |
|
|
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| Physical Properties: |
| Crystal structure |
cubic |
| Grain size |
diameter |
2 - 8µm |
| Density |
(g cm-3@298K) |
4.09 |
| Resistivity |
(W-cm) |
~1012 |
| Chemical Purity |
(%) |
99.9996 |
| Dielectric constant data is available from Rohm and Haas. |
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| Thermal
Properties: |
| Coefficient of Thermal Expansion |
| |
(1/K @ 273 K) |
6.6 x 10-6 |
| (1/K @ 373 K) |
7.3 x 10-6 |
| (1/K @ 473 K) |
7.7 x 10-6 |
| Thermal conductivity |
| |
(J/K-m-s @ 298 K) |
16.7 |
| Heat Capacity |
(J/g-K @ 298 K) |
0.469 |
| Maximum operating temperature will depend on
the environment |
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| Mechanical Properties:
|
| Hardness: |
Knoop, 50 gm load (kg mm-2) |
200 - 235 |
| |
Vickers, 1 kg load (kg mm-2) |
230 |
| Flexural Strength (modulus of rupture) |
| |
4 pt. loading (psi) |
15 x 103 |
| 4 pt. loading (MPa) |
103 |
| Disc. Bursting (MPa) |
84 |
| Fracture toughness (critical stress intensity factor, KIC
values) |
| |
(MPa ,
Vickers, 100g) |
0.8 |
| Young's Modulus (elastic modulus) |
| |
(psi) |
10.8 x 106 |
| (GPa) |
74.5 |
| Poisson's ratio |
0.29 |
| Rain erosion resistance will depend on the environment |
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