rubber formulations.) If the zinc compound then migrated to the surface of the bladder or "bloomed", it could react with the nickel ions which had been found to be present in the glycol solution to form Compound III.
A new bladder t h a t had a gray-white bloom was found. T h e infrared spect r u m of the bloom matched t h a t of the zinc analog of Compound III, completing the solution of the analytical problem.
The "Great Green Plague" Unfortunately, not all analytical problems undertaken in the laboratory have neat answers. Corrosion products of stainless steel are frequently found on various samples, but the exact composition of the corrosion product depends on the type of alloy, the corrosive compound(s), and the time the alloy has been exposed to the
corrosive compound(s). T h e product most frequently identified is a hydrated iron oxide, a composition which is consistent with environmental corrosion caused by the Florida coastal climate. However, not all corrosion is due to the environment. One example of this was a stainless steel tubing contaminant found when a mobile launcher t h a t had been downmoded after use in the Apollo program was being refurbished for use in the Skylab program. A brownishto-dark olive drab material t h a t occurred on the interior surface of some of the tubing was found by emission spectroscopy to contain major iron, manganese, and chromium; minor nickel and silicon; and traces of tin and five other metals. T h e numerous individual corrosion products, however, could not all be identified. T h e major ones identified by x-ray diffraction were iron oxide (Fe^C^), chromic oxide (Cr20,i), and manganese oxide (Mn,j04). These highly oxidized compounds were unusual compared to the hydrated iron oxides commonly found. Eventually, hundreds of feet of tubing were found to be contaminated with the "great green plague", and one office in the lab began to resemble a tubing farm as more and more sam-
ples were submitted for analysis. T h e cause of the contamination could not be definitely identified, but it was concluded t h a t the olive drab contaminant most probably was formed during the final annealing stage of the fabrication process. T h e problem was solved by replacing most of the tubing. After cleaning which involved pickling, some of the contaminated tubing was later used in less critical systems.
Acknowledgment T h e analytical contributions by coworkers L. G. Bostwick, R. Burton, W. R. Carman, W. A. Holden, J. F. Jones, R. M. Nichols, T. A. Schehl, L. D. Underbill, former coworkers K. Stevens, and A. C. Danielson of the Uniroyal Corp. are gratefully acknowledged.
References (1) L. G. Bostwick and R. Burton, "Combined Electron Microscope, Electron Diffraction, and Electron Microprobe Analysis of Identical Microstructures in the Debond Area of a Dissimilar Metal Joint", NASA TN D-6327, August 1971. (2) H. D. Bullard, L. D. Underhill, and G. L. Baughman, "Turbidimetric Determination of Sulfite Ion in Inhibited Ethylene Glycol-Water Solutions", KSC-TR1073, September 1970.
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