Analysis of Thermally Sprayed Nylon Splats

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Analysis of Thermally Sprayed Nylon Splats

• Jeremy Baldoni
• DREAM Fellow
• 7/28/05

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Schematic of Thermal Spray
2. Heat and gas flow turn the material into a
stream of fast moving molten droplets
1. Material starts as a solid (powder)
3. Material coats substrate with finite number
of small splats, solidifies
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Applications of Thermal Spray1

• Industries
• Aerospace
• Automotive
• Marine
• Printing
• Infrastructure

• Purposes
• Wear Prevention
• Thermal Insulation
• Corrosion Resistance

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High Velocity Oxy-Fuel (HVOF)

• HVOF particles have
• Less dwell time
• Greater kinetic energy
• than in traditional T.S.

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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

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Philadelphias Benjamin Franklin Bridge
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My Project Splat Analysis
3D Computer Modeling
SEM, Optical Inspection
Analysis of HVOF Sprayed Nylon Splatting Behavior
Understanding T.S. of Nylon Could Make Potential
Applications a Reality
Isolated nylon splat on flat glass (fried egg)
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Single vs. Multiple Passes (Optical)

• Variety of splat shapes, sizes
• Difficult to see splatsubstrate and splatsplat
  interface

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Cross Sections of Splats (Optical)
1000x Polished Steel
1000x Polished Steel

• One splat is flat, one is rounded--why?

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Polished Steel, GB50 Steel Cross Sections
(Optical)
Polished Steel 1000x
Steel Grit Blasted with 50 Mesh Grit (GB50)1000x

• Grit blasted specimen appears to allow for
  greater mechanical splatsubstrate interlocking

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Glass Several Splats (SEM)
As Delivered Glass
Glass GB120
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Glass Single Splats (SEM)
Smooth Glass
Glass GB120
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GB120 Glass Zoom

• What is the extent of splatsubstrate
  interlocking?

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Steel Several Splats (SEM)
Polished
GB120
GB50
GB12
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Steel Single Splats (SEM)
GB120
Polished
GB50
GB12
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Computer Modeling Flow-3D
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Flow-3D Examples

• Preliminary splat imagesseveral variables
  ignored
• Good stepping stone to more realistic roughnesses

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Next Steps Roughness Project

• Better SEM images of splats on rough substrates
• Cross section images of each substrate roughness
• Computer modeling on increasingly realistic
  substrate roughness representations
• Comparison of actual splats to model predictions
• Use model to predict beyond experimental results

Ultimate goal determine how nylon needs to be
sprayed so that it can become widely used
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Citations

• 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.h
  tm?keykveus1065dirbridgestpecat .