1 Hard Anodizing of Aerospace Aluminum Alloys Leonid M. Lerner IMFAIR O9 Royal Air Force Museum, Cosford, UK

2 Introduction During the twentieth century aluminum became an essential metal in the aircraft industry. Beginning with the cylinder block of the engine that powered the Wright brother's plane at Kitty Hawk in 1903, which was a one-piece casting in an aluminum alloy containing 8% copper, the use of aluminum has grown.

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8 “Burning”- rapid catastrophic dissolution of aluminum during the hard anodizing process Watts = Amps x Volts = Heat Burning Air agitation Cooling of electrolyte Organic additive Correct current density Sanford Low Voltage DC+AC Processes Prevention: -O2-O2 -O2-O2 -O 2 -O2-O Al 2 O 3 +H

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Our study in Table # 1,Columb 10 shows: 3. The Low Voltage DC + AC process with organic additive produced significant energy savings when compared to HV DC process with organic additive. The power draw for Low Voltage DC + AC (prorated) was 57 and 137 kWhr/64 (prorated) respectively. This represents savings of 63% and 22% respectively when compared to HV DC with additive. 15

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20 Comparative Data for Hard Anodizing of 2xxx Series Aluminum Alloys

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22 Sanford Low Voltage Process

23 Sanford Low Voltage Process

24 Uniformity of hard oxide film after Sanford Low Voltage Process

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26 Weight Loss, mg Thickness, mil Relationship of weight loss with Low Voltage coating thicknesses for 7075, 6061 and 2024 alloys.

Dependence of the Low Voltage Hard Anodizing time upon coating thickness for the three alloys 2024, 6061 and Anodizing Time, min Thickness, mil

28 CURRENT TIME The behaviors of Current during the procedure in High Voltage Hard Anodizing Process vs. Low Voltage Hard Anodizing

29 TIME VOLTAGE The behaviors of Voltage during the procedure in High Voltage Hard Anodizing Process vs. Low Voltage Hard Anodizing

30 Sanford Low Voltage Process

31 Sanford - Quantum Color Hard Anodizing Sanford Low Voltage Hard Anodizing Processes Sanford +Plus Hard Anodizing Sanford Salvage Hard Anodizing

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