Analysis of Thermally Analysis of Thermally Sprayed Nylon SplatsSprayed Nylon Splats
Jeremy Baldoni
DREAM Fellow
7/28/05
Advisors:
Mentors:
Dr. Richard KnightDr. Richard A. Cairncross
Mr. Milan IvosevicMr. Varun Gupta
Schematic of Thermal SpraySchematic of Thermal Spray
3. Material coats substrate with finitenumber of small splats, solidifies
2. Heat and gas flow turn the material into a stream of fast moving molten droplets
1. Material starts as a solid (powder)
Applications of Thermal SprayApplications of Thermal Spray11
Industries Aerospace Automotive Marine Printing Infrastructure
Purposes Wear Prevention Thermal Insulation Corrosion Resistance
High Velocity Oxy-Fuel (HVOF)High Velocity Oxy-Fuel (HVOF)
HVOF particles have: Less “dwell time” Greater kinetic energythan in traditional T.S.
2
Why HVOF with Nylon 11?Why HVOF with Nylon 11? HVOF is powerful
yet practical in the field
Nylon 11 is versatile and useful
Currently, dangerous VOCs are used as Nylon 11 solvents
3
Philadelphia’s Benjamin Franklin Bridge
My Project: Splat AnalysisMy Project: Splat Analysis
Isolated nylon splat on flat glass (fried egg)
3D ComputerModeling
SEM, Optical Inspection
Analysis of HVOF Sprayed Nylon
Splatting Behavior
Understanding T.S. of Nylon Could Make Potential Applications a Reality
Single vs. Multiple Passes (Optical)Single vs. Multiple Passes (Optical)
Variety of splat shapes, sizes Difficult to see splat:substrate and splat:splat interface
Flat glass 200x: Single Pass Flat glass 200x: Three Passes
Cross Sections of Splats (Optical)Cross Sections of Splats (Optical)
1000x Polished Steel 1000x Polished Steel
One splat is flat, one is rounded--why?
Polished Steel, GB50 Steel Polished Steel, GB50 Steel Cross Sections (Optical)Cross Sections (Optical)
Polished Steel 1000x Steel Grit Blasted with 50Mesh Grit (GB50)1000x
Grit blasted specimen appears to allow for greater mechanical splat:substrate interlocking
Glass: Several Splats (SEM)Glass: Several Splats (SEM)
As Delivered Glass Glass GB120
Glass: Single Splats (SEM)Glass: Single Splats (SEM)
Smooth Glass Glass GB120
GB120 Glass ZoomGB120 Glass Zoom
What is the extent of splat:substrate interlocking?
Steel: Several Splats (SEM)Steel: Several Splats (SEM)Polished
GB120
GB50 GB12
Steel: Single Splats (SEM)Steel: Single Splats (SEM)
Polished
GB50
GB120
GB12
Computer Modeling: Flow-3DComputer Modeling: Flow-3DFlat Substrate
Simple computer generated roughened substrates
Actual GB steel substrate representation- Zygo
Flow-3D ExamplesFlow-3D Examples
Preliminary splat images—several variables ignored Good stepping stone to more realistic roughnesses
Next Steps: Roughness ProjectNext Steps: Roughness Project
Better SEM images of splats on rough substratesCross section images of each substrate roughnessComputer modeling on increasingly realistic
substrate roughness representationsComparison of actual splats to model predictionsUse model to predict beyond experimental results
Ultimate goal: determine how nylon needs to be sprayed so that it can become widely used
CitationsCitations 1. J.R. Davis (editor): Handbook of Thermal Spray Technology, ASM International, Materials Park,
OH, 2004. 2. Technical Paper Thermal Spraying, Air Products and Chemicals Inc. accessed July 15, 2005,
http://www.airproducts.com/Products/CylinderGases/MAXX/ThermalSpraying/thermalspraying_techpaper.htm .
3. Benjamin Franklin Bridge, Philadelphia, A View On Cities, accessed July 18 2005, http://www.aviewoncities.com/gallery/showpicture.htm?key=kveus1065&dir=bridges&tpe=cat .