identification and validation of analytical chemistry ... · – sam hill, yao ge, shejie tang,...
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The Joint Advanced Materials and Structures Center of Excellence
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Identification and Validation of Analytical Identification and Validation of Analytical Identification and Validation of Analytical Identification and Validation of Analytical Identification and Validation of Analytical Identification and Validation of Analytical Identification and Validation of Analytical Identification and Validation of Analytical Chemistry Methods for Detecting Composite Chemistry Methods for Detecting Composite Chemistry Methods for Detecting Composite Chemistry Methods for Detecting Composite Chemistry Methods for Detecting Composite Chemistry Methods for Detecting Composite Chemistry Methods for Detecting Composite Chemistry Methods for Detecting Composite
Surface Contamination and Moisture Surface Contamination and Moisture Surface Contamination and Moisture Surface Contamination and Moisture Surface Contamination and Moisture Surface Contamination and Moisture Surface Contamination and Moisture Surface Contamination and Moisture XiangyangXiangyang ZhouZhou
University of MiamiUniversity of Miami
Rajiv Srivastava and Richard BurtonRajiv Srivastava and Richard BurtonFlorida International UniversityFlorida International University
2The Joint Advanced Materials and Structures Center of Excellence
Identification and Validation of Analytical Chemistry Methods Identification and Validation of Analytical Chemistry Methods Identification and Validation of Analytical Chemistry Methods Identification and Validation of Analytical Chemistry Methods
for Detecting Composite Surface Contamination and Moisturefor Detecting Composite Surface Contamination and Moisturefor Detecting Composite Surface Contamination and Moisturefor Detecting Composite Surface Contamination and Moisture
• Motivation and Key Issues – Adhesive bonding has been used in the manufacture and
repair as a direct competition to mechanical fasting. – Adherend surface preparation is a critical issue to the
structural integrity and durability of bonded structures. • Objective
– benchmark surface preparation quality assurance methods – identify and validate definitive analytical chemistry methods
to provide sufficient in-field quality assurance.• Approach
– Literature review and analysis– Surface chemistry analysis– Electrochemical sensor development– Experimental validation
3The Joint Advanced Materials and Structures Center of Excellence
FAA Sponsored Project Information
• Principle Investigators & Researchers– Xiangyang Zhou, Richard Burton– Rajiv Srivastava, Dwayne McDaniel, Weihua Zhang,
Wongbon Choi, – Sam Hill, Yao Ge, Shejie Tang, Ling Wang (Graduate
Students)• FAA Technical Monitor
Curtis Davies• Industry Participation
– DME Corporation 6830 N.W. 16th TerraceFort Lauderdale, Florida 33309 USA
4The Joint Advanced Materials and Structures Center of Excellence
Main Results
– Literature database
– Summary of literature review• Surface treatment• Surface chemistry analyses
– An electrochemical sensor for surface chemistry analysis
– Novel carbon nanotube sensor for humidity sensing
– AFM study of the peel plies
5The Joint Advanced Materials and Structures Center of Excellence
Information collection and analyses
Strength & durability versus surface
pretreatment
Chemical analyses Surface analysis criteria
Information collection and analyses
Candidate field analysis technologies
Technology validation Effective field analysis technology
Research Roadmap
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Literature Database
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Effect of Various Surface Pretreatment Method
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Covalent bond formation between adherend and adhesive-Effect of Surface O- and N- Functional
Groups (Anchor Groups)
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Concentration of O versus Strength
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Quality Control
• Materials certification,• Pretreatment certification• Adhesive application certification, • Bonding certification,• Technician certification,
• Process flow management
)(criticalNN adsorbedadsorbed <)critical(NN N&ON&O −−−− >
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Electrochemical Sensor
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Solid-State Electrochemical Sensor
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Solid-state Electrochemical Sensor
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Solid-state Electrochemical Sensor
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Test results
Zreal , Ohm
0 5 10 15 20 25
-Zim
a, O
hm
-25
-20
-15
-10
-5
0
105 Hz
33 Hz
0.2 Hz
16The Joint Advanced Materials and Structures Center of Excellence
Test Results
Potential / Volts (vs. Pt|H2 electrode)
-0.8 -0.6 -0.4 -0.2 0.0 0.2 0.4 0.6 0.8
Cu
rren
t / A
mp
ers
-0.0010
-0.0008
-0.0006
-0.0004
-0.0002
0.0000
0.0002
0.0004
0.0006
1st cycle2nd cycle3rd cycle4th cycle5th cycle
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Carbon Nanotube Based Humidity Sensor
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Atomic Force Microscopy Study of Atomic Force Microscopy Study of Atomic Force Microscopy Study of Atomic Force Microscopy Study of Peel PlyPeel PlyPeel PlyPeel Ply
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θπσ
cos4max
R
F=
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Atomic Force Microscope
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Previous SEM and XPS Results on Peel Ply Surfaces
• Polyester (PF 60001): No transfer, strong bonds
• SRB (PF 60001): Siloxane coating transfer, weak bonds
• Nylon (PF 52006): Fiber transfer, bond strength depends on adhesive
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Nylon Peel Ply Surface
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Polyester Peel Ply Surface
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SRB Peel Ply Surface
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Force vs. distance for nylon peel ply surface
- 1 5 0 0 - 1 0 0 0 - 5 0 0 0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0
- 6
- 4
- 2
0
2
4
6
- 1 5 0 0 - 1 0 0 0 - 5 0 0 0 5 0 0 1 0 0 0 1 5 0 0 2 0 0 0
- 6
- 4
- 2
0
2
4
6
Forc
e (a
rb. u
nit)
z (micrometers)
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Force vs. distance for SRB peel ply Surface
-1500 -1000 -500 0 500 1000 1500 2000 2500
-10
-8
-6
-4
-2
0
2
4
6
-1500 -1000 -500 0 500 1000 1500 2000 2500
-10
-8
-6
-4
-2
0
2
4
6
Forc
e (a
rb. u
nit)
z (micrometers)
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Conclusions
• Certification of pre-bond surface preparation quality requires implementation of effective surface chemistry inspection technologies for each and every step of the surface preparation procedure to ensure the strength and durability of the bonded aviation structures.
• Solid-state electrochemical sensor is a promising candidate technology for in-field surface chemistry analysis
29The Joint Advanced Materials and Structures Center of Excellence
Conclusions
• No sign of contamination was found on polyester peel ply surface
• Some small size particles were found on nylon peel ply surface
• Some contaminating particles were found on SRB peel ply surface
• The SRB surface shows a more complicated force spectrum than the nylon peel ply surface.
30The Joint Advanced Materials and Structures Center of Excellence
A Look Forward
• Benefit to Aviation– Better understanding of the pre-bond surface preparation
methods– Better understanding of bond strength and durability versus
surface preparation– Novel in-field, online certification and assurance technology for
surface preparation– Reduced costs for surface preparation and adhesive bonding
processes
• Future needs– In-field, online analytical detection and monitoring technologies
for manufacture, chemical, environmental, and energy industries.
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