Accession Number : ADA309214

Title :   Erosion Characteristics and Optical Properties of State-of-the-Art, Erosion-Resistant Coatings on Infrared Windows: Boron Phosphide, Gallium Phosphide, and Zinc Sulfide on Multispectral Zinc Sulfide.

Descriptive Note : Summary rept. Oct 94-Aug 95,

Corporate Author : NAVAL AIR WARFARE CENTER WEAPONS DIV CHINA LAKE CA

Personal Author(s) : Harris, Daniel C.

PDF Url : ADA309214

Report Date : MAY 1996

Pagination or Media Count : 67

Abstract : Optical properties and rain and sand erosion resistance of the following infrared window materials were measured: (1) Barr & Stroud boron phosphide coating on multispectral zinc sulfide, (2) Barr & Stroud gallium phosphide coating (with a thin outer layer of boron phosphide) on multispectral zinc sulfide, (3) Raytheon zinc sulfide coating on multispectral zinc sulfide, (4) Texas Instruments bulk gallium phosphide, (5) polycrystalline magnesium fluoride, and (6) single-crystal silicon. ZnS-coated ZnS has low optical emission for operation at 500 deg C in both the 3-5 and 8-10 micrometers regions. Bulk GaP and bare MgF2 have low emission only in the 3-5 micrometers region. BP/ZnS and BP/OaP/ZnS have prohibitive optical emission at 500 deg C in both the 3-5 and 8-10 micrometers regions. In whirling arm rain erosion experiments, none of the coated materials was as durable as bare MgF2. BP/ZnS is more durable than ZnS/ZnS, but subsurface damage preceded damage to the BP coating in BP/ZnS. GaP fractured easily on orthogonal crystal planes upon raindrop impact. In sand erosion experiments, BP and BP/GaP/ZnS were best and MgF2 was second most durable.

Descriptors :   *OPTICAL COATINGS, *ANTIREFLECTION COATINGS, *WEAR RESISTANCE, *EROSION RESISTANCE, *INFRARED WINDOWS, LIGHT SCATTERING, OPTICAL PROPERTIES, CRYSTAL STRUCTURE, ZINC SULFIDES, SAND, RAIN, LIGHT TRANSMISSION, PROTECTIVE COATINGS, PHOSPHIDES, INFRARED RADIATION, BORON, FLUORIDES, INFRARED OPTICAL MATERIALS, MULTISPECTRAL, RAIN EROSION, POLYCRYSTALLINE, GALLIUM PHOSPHIDES, ZINC COATINGS.

Subject Categories : Coatings, Colorants and Finishes
      Optics
      Mechanics

Distribution Statement : APPROVED FOR PUBLIC RELEASE