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Preventing Cracking of Anodized CoatingsAnodized coatings have been used as optical and thermal surfaces in spacecraft. Particulate contamination from cracked coatings is a concern for many applications. The major cause for the cracking is the difference in the coefficient of thermal expansion between the oxide coatings and the aluminum substrate. The loss of water when the coating is exposed to a vacuum also could induce cracking of the coating. Hot-water sealing was identified as the major cause for the cracking of the coatings because of the large temperature change when the parts were immersed in boiling water and the water was absorbed in the coating. when the hot-water sealing process was eliminated, the cracking resistance of the anodized coatings was greatly improved. Also, it was found that dyed black coatings were more susceptible than clear coatings to cracking during thermo-vacuum cyclings.
Document ID
Document Type
Technical Memorandum (TM)
He, Charles C. (Unisys Corp. Greenbelt, MD, United States)
Heslin, Thomas M. (NASA Goddard Space Flight Center Greenbelt, MD, United States)
Date Acquired
September 6, 2013
Publication Date
August 1, 1995
Subject Category
Report/Patent Number
NAS 1.15:104622
Distribution Limits
Work of the US Gov. Public Use Permitted.

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NameType 19950025269.pdf STI