NITROGEN TETROXIDE-STAINLESS STEEL CRYOPANEL CORROSION AND COATING DEGRADATION IN SPACE CHAMBER PROPULSION TESTING
Rept. for Oct 1965-30 Jun 1966
ARNOLD ENGINEERING DEVELOPMENT CENTER ARNOLD AFB TN
Pagination or Media Count:
Corrosion of cryopanel metals in space simulation chambers caused by contamination by fuels, oxidizers, or exhaust gases arising from propulsion systems testing may be a serious problem. Since data taken under operational conditions is needed, a preliminary study using nitrogen tetroxide and 300- series stainless steel was initiated. The temperature was cycled between ambient conditions and 77K, and the pressure between 4 and 0.00001 torr of oxidizer. A black epoxy film covered some of the samples. Welded stainless steel 304 sustained general corrosion with some pitting, and intergranular corrosion was detected in heat-sensitized weld areas. Epoxy coated stainless steel 304 samples demonstrated no apparent damage in one series of short tests, but pit formation in the coating, pitting beneath the coating, and intergranular corrosion in weld areas was detected in a longer test. Heat-treated and polished stainless steel 304-L pitted to an indeterminate depth. An epoxy coated sample of similar material suffered microscopic cracking and blistering of the coating and surface pitting beneath.
- Properties of Metals and Alloys
- Solid State Physics