Packaging, VCI, And Dehumidification Field Evaluation

1
Packaging, VCI, And Dehumidification Field
Evaluation

• W.H. AbbottBattelle-ColumbusColumbus, Ohio
• J.L. Jackson Battelle-ColumbusColumbus, Ohio
  
  

2
Overview Field Studies

• A Variety Of Equipment Protection Methods For
  Short And Long-Term Storage Are Being
  Quantitatively Evaluated During Exposures In A
  Severe, Atlantic Coastal Environment Daytona
  Beach , FL
• Cabinet/Enclosure Storage With 3 Independent
  Levels Of Protection And Controlled Air
  Exchange/leakage ( 1 Turnover per hour)
• Dehumidification (Munters)
• VCI (Cortec)
• No Protection
• Packaging (COTS Products 4-6 mil Thick) In
  Outdoor Exposures
• Transhield
• Zerust
• Intercept Shield
• Cortec
• Clear Polyethylene
• Uncontrolled Indoor Storage
• Uncontrolled Outdoor/Minimal Shelter Storage

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Objectives

• Quantify Conditions Inside Cabinets and Packaging
  To Define Benefits In Severe Environments
• Temperature
• Humidity
• Chlorides
• Corrosion Rates On Coupons and Components
• Metals
• Plastics
• Galvanic Couples
• Electrical Connector
• Electronic Test Item Under Power/Electromigration
• Define Limitations Of Current Technologies In
  Field Ops

4
Field Installed Cabinets ( 2 Of 3)
1 Dehumidification
2VCI TabletAir Exchange Pump and Samples
Unprotected Test Items Inside
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Packaged Test Items (Outside Cabinets)

• COTS Bags (4-6 mils per vendor recommendations)
• Tape Sealed (per vendor recommendations in
  field)
• Standard Monitoring Package Inside (Lower Right)
• Evaluate/Open Every 3 Months

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Early Test Results Cabinets _at_ 11 Months

• Similar Humidity Distributions Inside All
  Cabinets
• Outside gt70 for 90 of time
• Slightly Favorable With Dehumidification _at_ 50
  rh Setpoint
• Corrosion
• Outside Very Severe
• Inside Corrosion Very Low
• 1010 Steel Barely Visible Rust
• Actual wt. Loss 200 x Lower Inside

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Typical Humidity Cycling In Cabinets With And
Without Dehumidification And Performance Of
Powered Electronics Test Item
Intermittent Hits On Powered Item
No Evidence Of Electromigration On Powered Item
(IPC Test Card)
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Early Conclusions -- Cabinets

• Sheltering Effect Again Shown To Be Very Strong
  In Lowering Corrosion Rates
• Major Effect Is Reduced Chloride Exposure
• Humidity Alone Often Not Sufficient To Drive
  Corrosion On Structural Parts In Storage
• Chloride-Humidity Synergism Very Strong
• All Cabinet-Protection Schemes May Be Adequate
  For Structural Parts But At Or Below Currently
  Attained Humidity Distributions And Chlorides
• Only Advantage For Dehumidification May Be For
  Electronics Systems VCI Protection Close Second

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Early Conclusions Outside Packaged Products

• Problems Encountered During Early Testing (lt6
  months)
• Bag Durability Pinholes and Tears Due To
  Flexing In Wind
• Inadequate Tape Seals Even With Care (Rapid
  Moisture Ingress)
• Inability To Reuse Some Bag/Tape Combinations
• No Combinations Performed Well During Initial
  Rounds
• Second Round Initiated December 04
• Thicker Bags (6 mils) Where Available
• Government Grade Bags Where Available
• Best Tapes Per Vendor Recommendations
• Enhanced Test Package To Include T-H Recorders
  and Powered Electronics Test Item

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Temp-Humidity Inside Sealed Outdoor Bag Start
8/2/04

• Example Shows Very Rapid Moisture Ingress (Few
  Days)
• Once Moisture Inside, Wont Come Out
• Humidity Cycling Due To Diurnal Temperature Cycles

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Corrosion Example Outside Package 4 Months

• Rapid Corrosion Of 1010 Steel (gtgt than in
  cabinets)
• Rapid Corrosion Al/St Galvanic Couple
• Visible Corrosion KC135 Wing Skin Test Item
  (Galvanic)

KC135 Wing Skin Al with Steel Fasteners
1010 Steel
Al/Steel Lapjoint
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Conclusions

• Packaging Studies Well Under Way
• Cabinet Exposures Show High Level Of Corrosion
  Attenuation
• Good Corrosion Protection For Structural Metal
  Parts
• Dehumidification Possibly Justified For
  Electronics Storage
• Conclusions Regarding VCI Still Open
• Benefits Due Mainly To Sheltering/ Chloride
  Reduction
• Basis Established For Setting Humidity/Chloride
  Limits For Protection
• Packaging Studies Identifying Deficiencies
• Bag Integrity/Mechanical
• Seal Integrity Major Problem
• Studies Underway With Thicker Bags and Best
  Available Tape