Diffuse absorbing beryllium coatings produced by magnetron sputtering
- Oak Ridge National Lab., TN (USA)
- Brigham Young Univ., Provo, UT (USA). Dept. of Physics and Astronomy
Beryllium coatings with varying thicknesses and columnar grain sizes were deposited by low temperature magnetron sputtering and then wet chemically etched to enhance diffuse absorption of light. After etching these coatings exhibited a mate black surface finish and low specular reflectance (below 2%) in the IR up to a critical wavelength dependent upon the original grain size of the coating. Extremely thick coatings (300 um) with original grain sizes of 10 to 12 um have been produced which exhibited specular reflectances below 0.5% up to 50 um wavelength and a Lambertian BRDF at 10.6 um averaging 4.3 {times} 10{sup {minus}3} ster{sup {minus}1}. Scanning electron microscopy results are presented for etched and unetched beryllium coatings which showed the etching process produces roughness and porosity over several size scales simultaneously with the maximum size scale limited by the initial coating grain size. This technique for producing diffuse absorbing baffle materials has great versatility in choice of coating material and substrate and can be expected to provide optical system designers with a variety of material options for stray light management.
- Research Organization:
- Oak Ridge National Lab., TN (USA)
- Sponsoring Organization:
- DOD
- DOE Contract Number:
- AC05-84OR21400
- OSTI ID:
- 7156120
- Report Number(s):
- CONF-900756-8; ON: DE90012945
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
360101 -- Metals & Alloys-- Preparation & Fabrication
360104* -- Metals & Alloys-- Physical Properties
ABSORPTION
ALKALINE EARTH METALS
BERYLLIUM
COATINGS
CRYSTAL STRUCTURE
DEPOSITION
ELECTRON MICROSCOPY
ELEMENTS
GRAIN SIZE
METALS
MICROSCOPY
MICROSTRUCTURE
OPTICAL PROPERTIES
PHYSICAL PROPERTIES
SCANNING ELECTRON MICROSCOPY
SIZE
SPUTTERING