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.

318 JOURNAL OF THE SOCIETY OF COSMETIC CHEMISTS TABLE II--CoMPATIBILITY TESTS OF 1100-H14 ALUMINUM WITH FLUOROCARBONS, ETHYL ALCOHOL AND WATER AT AMBIENT TEMPERATURE Corn- Expo- posi- sure Expo- Weight tion, Time, sure Loss, Chemicals % days Observations Phase gm. Fluorocarbon 11 90 Water 10 Fluorocarbon 11 90 Water 10 Fluorocarbon 11 90 Water 10 Fluorocarbon 12 90 Water 10 Fluorocarbon 12 90 Water 1t3 Fluorocarbon 12 90 Water 10 Ethyl alcohol (95%) 90 Water 10 Ethyl alcohol (95%) 90 Water 10 Ethyl alcohol (95%) 90 Water 10 Fluorocarbon 11 45 Ethyl alcohol (95%) 50 Water 5 Fluorocarbon 11 45 Ethyl alcohol (95%) 50 Water 5 Fluorocarbon 12 45 Ethyl alcohol (95%) 50 Water 5 Fluorocarbon 12 45 Ethyl alcohol (95%) 50 Water 5 Fluorocarbon 11 25 Ethyl alcohol (95%) 50 Water 25 Fluorocarbon 11 25 Ethyl alcohol (95%) 50 Water 25 Fluorocarbon 12 25 Ethyl alcohol (95%) 50 Water 25 Fluorocarbon 12 25 Ethyl alcohol (95%) 50 Water 25 Fluorocarbon 12 25 Ethyl alcohol (95%) 50 Water 25 Fluorocarbon 11 22.5 Fluorocarbon 12 22.5 Ethyl alcohol (95%) 45 Water 5 18 No visual corrosion Liquid ... No visual corrosion Vapor ... 68 No visual corrosion Liquid ... No visual corrosion Vapor '" 414 One pit evident Liquid 0.0007 Very shallow pitting Vapor 0.0011 18 No evidence of corrosion Liquid ... No evidence of corrosion Vapor ... 68 No evidence of corrosion Liquid ... No evidence of corrosion Vapor ... 414 Slight blister at one corner Liquid 0.0007 No corrosion evident Vapor 0.0002 18 No evidence of corrosion Liquid . .. No evidence of corrosion Vapor ... 68 No evidence of corrosion Liquid ... No evidence of corrosion Vapor . .. 414 Localized shallow corrosion Liquid 0.0061 No evidence of corrosion Vapor 0.0001 18 Pitting corrosion--sediment Liquid ... Pitting corrosion Vapor ... 67 Pitting corrosion7-sediment Liquid 0.0796 Pitting corrosion Vapor 0.0780 18 Pitting corrosion--sediment Liquid ... Possible pitting Vapor ... 67 Pitting corrosion--sediment Liquid 0.0064 Possible pitting Vapor 0.0023 18 No obvious corrosion Liquid No obvious corrosion Vapor 102 Pitting corrosion--sediment Liquid 0.2047 Pitting corrosion Vapor 0.0710 18 No obvious corrosion Liquid No obvious corrosion Vapor 68 Very minor pitting Liquid Very minor pitting Vapor 414 Pitting along edges Liquid 0.0049 Some localized shallow corrosion Vapor 0.0026 18 Pitting--sediment Liquid No pitting Vapor (Continued)