Effects of WashRinse Intervals On Corrosion Early Results Of A Ground Based Study

1
Effects of Wash-Rinse Intervals On Corrosion
Early Results Of A Ground Based Study

• W.H. Abbott Battelle-Columbus
• Richard Kinzie AFCPO Warner Robins

2
Introduction

• Why Do We Presently Wash Aircraft ?
• Corrosion Control ?
• Cosmetics ?
• Present Policy Is To Wash At Specified Intervals
  Based On Environmental Severity (ESI)
• Recent But Cursory Studies Suggest That This
  Policy Should Be Examined Further

3
Study Objectives

• Develop Quantitative Data On Effects Of
  Wash-Rinse Intervals On Corrosion Rates
• Study In Real Environments
• Study At Different Severity/ESI Levels
• Use Realistic Wash and Rinse Procedures
• Obtain Real-Time Corrosion Rate Data Using
  Corrosion Sensor technology

4
Experimental Approach

• Utilize Metallic Corrosion Sensors As Test
  Vehicle
• Same Sensors As Being Flight Tested
• Mounted Vertically In Multiple, Outdoor
  Environments Differing Widely In Severity
• Wash And Rinse Independent Sensors At Fixed
  Intervals
• Wash With 5 BB Regel In Local Tap Water
• Rinse By Spray With Local Tap Water
• Air Dry Naturally
• Measure Monthly As Electrical OutputCumulative
  Corrosion

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Experimental (Contd)

• Exposure Locations ESI (percentile)
• Daytona Beach (75 meters) 95(very severe)
• Daytona Beach (1/4 mile inland) 75 (severe)
• Central Ohio (WPAFB ESI) 50 (moderate)
• Warner Robins 30 (mild)
• Wash Intervals Studied No Wash, 1,2,4,7,14,28
  days
• Photo Typical Samples On Fence
• 3 sets Duplicate Samples (0,1,2 days)
• ESI Test Rack (not washed)

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Worldwide ESI Distribution vs. Wash-Rinse Site
ESI
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Example Of Corrosion Kinetics Daytona 75 m.

• Data Show Consistent Progression Of Degradation
• Validation of Techniques
• Benefits Not Immediately Apparent

8
Corrosion vs. Wash Interval Daytona 75 m.

• Data Show Benefit/ Minimum Corrosion
• Increasing Benefit With Time But Lost If Extended
  gt 20 days
• Max Benefit _at_ 1-2 Days

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Corrosion vs. Wash Interval Daytona ¼ mi. Inland

• Benefit But Note Scale Change
• Smaller Benefit But Measurable
• Max Benefit _at_ 1-2 Days But Gone Within Extend gt 7
  Days

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Corrosion vs. Wash Interval Central Ohio

• Slight and Questionable Benefit

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Corrosion vs. Wash Interval Warner Robins

• No Apparent Benefit
• Results Actually Suggest Increased Corrosion
• Reasons Not Defined
• Water Quality Issue ?

12
Conclusions

• Early Results Raise Questions About Wash-Rinse
  Benefits For Corrosion Control In Many
  Environments
• Reduced Corrosion Rates/Benefits Demonstrated
  Only For Severe Environments (gt70th percentile
  possibly gt90th )
• Only For Very Frequent Wash or Rinse (1-2 days)
• Effects Of Rinse Only Not Known (under study)
• Benefits May Be Lost If Wash Time Extended Beyond
  Few Days
• Results Must Be Confirmed On Operational Aircraft
  Before Any Changes To Existing Policy Recommended
• Results May Provide Basis For Relaxation Of
  Wash-Rinse Requirements If Verified