316 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS TABLE I--CoMPATIBILITY TESTS OF 1100-H14 ALUMINU• WIT• FI. UOROCARBONS ANt EThYl. ALCOHOL AT AMBIENT TEMPERATURE Corn- Expo- posi- sure Expo- Weight tion, Time, sure Loss, Chemicals % days Observations Phase g. F!uorocarbon 11 Fluorocarbon 11 Fluorocarbon 11 Fluorocarbon 12 Fluorocarbon 12 Fluorocarbon 12 Ethyl alcohol (95%) Ethyl alcohol (95%) Fluorocarbon 11 Ethyl alcohol (95%) Ethyl alcohol (95%) Fluorocarbon 11 Fluorocarbon 12 Ethyl alcohol (95%) Fluorocarbon 12 Ethyl alcohol (95%) Fluorocarbon 12 Ethyl alcohol (95%) Fluorocarbon 11 Fluorocarbon 12 Ethyl alcohol (95%) Fluorocarbon 11 Fluorocarbon 12 Ethyl alcohol (95%) Fluorocarbon 11 Fluorocarbon 12 Ethyl alcohol (95%) (5052-H34 alloy specimens) 100 21 No corrosion--no sediment Liquid ... No corrosion Vapor 100 68 No corrosion--no sediment Liquid ... No corrosion Vapor ... 100 414 No corrosion--faint sediment Liquid 0.00135 No corrosion Vapor 0. 0010 100 21 No corrosion--no sediment Liquid ... No corrosion Vapor ... 100 68 No corrosion--no sediment Liquid ... No corrosion Vapor ... 100 1049 No corrosion--no sediment Liquid 0.0011 No corrosion Vapor 0.0008 100 21 No corrosion--no sediment Liquid ... No corrosion Vapor ... 100 414 Localized shallow corrosion Liquid 0.0041 No apparent corrosion Vapor 0.0001 50 18 Visual pitting--sediment present Liquid ... 50 Visual pitting Vapor ... 50 67 Visual pitting--sediment present Liquid 0.0503 50 Visual pitting Vapor 0.0206 50 18 Visual pitting--sediment present Liquid . .. 50 Possible pitting Vapor ... 50 67 Visual pitting--sediment present Liquid 0.0026 50 Possible pitting Vapor 0.0004 50 387 Moderate localized corrosion Liquid 0.0046 50 No apparent corrosion Vapor 0.0004 25 18 Visual pitting--sediment present Liquid ... 25 Visual pitting Vapor ... 50 25 107 Deep pitting--sediment present Liquid 0.0362 25 Deep pitting ...... 50 25 185 Shallow pitting along edge Liquid 0.0048 25 No apparent corrosion Vapor 0.0001 50 * The actual weight losses are considered more meaningful than corrosion rates since the corrosion is usually not uniform over the aluminum surface nor is it progressing uniformly with time. three years. Very minor corrosion of aluminum in 95% ethyl alcohol was also noted after a few months. After one year of exposure, however, the metal weight loss would not be considered serious particularly since shallow etching type corrosion rather than localized pitting was encoun- tered. When fiuorocarbon 11 was combined with 95% ethyl alcohol, there was visual evidence of pitting on the aluminum in the ampule within a few

COMPATIBILITY STUDIES OF ALUMINUM 317 weeks. Weight losses obtained after two months of exposure were 20 (vapor phase) to 100 (liquid phase) times as great as found in fiuorocarbon 11 alone after one year. The aluminum weight losses in this combination solution in two months were similarly many times higher than in 95% ethyl alcohol solution alone after one year's exposure. It is of further interest to note that aluminum in the presence of fiuorocarbon 12 and 95% ethyl alcohol, while showing early evidence of corrosion after two weeks, sustained a much lower weight loss than in the combination of 95% ethyl alcohol and fluorocarbon 11. As might be anticipated, the combination of fiuorocarbons 11 and 12 shows an intermediate corrosivity when added to 95% ethyl alcohol. The degree of corrosivity may also vary with alloy, since 5052-H34 aluminum specimens showed only slight corrosion and minor weight loss after six months of exposure compared with deep pitting and highly significant weight loss for 1100-H14 alloy in a much shorter period. ALUMINUM COMPATIBILITY STUDIES WITH FLUOROCARBONS, ETHYL ALCOI•OL aND W^TV.]• The addition of 10% water to the individual fiuorocarbons or 95% ethyl alcohol did not significantly increase corrosion during exposure periods up to 414 days as shown in Table II and Fig. 2. An increase of about 50% in weight loss occurred when only 5% water was added to combinations offluorocarbons 11 or 12 and 95% ethyl alcohol. Increasing the water content of the solution by as much as 25-50% seemed to retard 320 A- 90% F-II, 10% H20 (414 DAYS) B - 90% F-12,10% H20 (414 DAYS) 280 C-90%(95%ETHYL ALCOHOL), I0% H20(414 DAYS) D- 50% (95% ETHYL ALCOHOL ),45% F-II,5% H20 (67 DAYS ) E- 50% (95% ETHYL ALCOHOL ),45% F-12,5% H20 (67 DAYS ) F- 50% (95% ETHYL ALCOHOL ), 25% F-I I, 25% H20 (102 DAYS ) 240 G 50%(95%ETHYL ALCOHOL),25%F-12 25%H20(414DAYS) _ H- 22.5%(ETHYL ALCOHOL),25% F-II,52.5% H20 (218 DAYS) F I ß LIQmD ,60 [] VAPO. D 120 8o 40 o Figure 2.--Comparison of corrosion weight losses of aluminum in solutions of propellants. ethyl alcohol, and water.