Splat Morphology of HVOF Splat Morphology of HVOF Thermally Sprayed NylonThermally Sprayed Nylon

Matt ChalkerMatt Chalker

Milan IvosevicMilan Ivosevic

Dr. Richard CairncrossDr. Richard Cairncross

GoalsGoals

Learn About Thermal Spray Learn About Thermal Spray ProcessesProcesses

Learn Modeling Software Flow-3DLearn Modeling Software Flow-3DCreate Video of Morphing Nylon Create Video of Morphing Nylon

SplatsSplatsDetermine Time Table for Splats from Determine Time Table for Splats from

Impact to SolidificationImpact to Solidification

Thermal SprayThermal Spray

Old Coating TechniqueOld Coating TechniqueMelting substance, spraying molten Melting substance, spraying molten

substance onto substratesubstance onto substrateMany processes, each suited for different Many processes, each suited for different

applicationsapplications

HVOF Thermal Spray of PolymersHVOF Thermal Spray of Polymers

HVOF Developed for CeramicsHVOF Developed for CeramicsPolymers attempted recentlyPolymers attempted recentlyCombustion occurs inside chamberCombustion occurs inside chamberThermal Conductivity lowThermal Conductivity lowTemperature/Phase Gradient DevelopsTemperature/Phase Gradient Develops

HVOF Thermal Spray of PolymersHVOF Thermal Spray of PolymersDiagramDiagram

Potential ApplicationsPotential Applications

Solventless PaintSolventless PaintGood Corrosion ResistanceGood Corrosion ResistanceGood Abrasion QualitiesGood Abrasion QualitiesGreat in Marine EvironmentsGreat in Marine EvironmentsGood Protection for Off-Shore Oil Rigs or Good Protection for Off-Shore Oil Rigs or

BridgesBridges

HVOF Spraying ParametersHVOF Spraying Parameters

Material - Pure Nylon-11 D-60Material - Pure Nylon-11 D-60 Substrate - Glass 1”x1”x1/16”Substrate - Glass 1”x1”x1/16” Spray Distance – 9” Spray Distance – 9” Max Transverse Velocity, 1 PassMax Transverse Velocity, 1 Pass HVOF Nozzle Length – 6”HVOF Nozzle Length – 6” Nozzle I.D. – 5/16”Nozzle I.D. – 5/16” OO22 Flow – 310 scfh Flow – 310 scfh

HH22 Flow – 695 scfh Flow – 695 scfh Powder Feed Setting – 0.8 rpmPowder Feed Setting – 0.8 rpm Powder Gas Flow – 80 scfhPowder Gas Flow – 80 scfh

Video of Splat MorphingVideo of Splat Morphing

• Splats not always dome shapedSplats not always dome shaped• Splats become “Fried Eggs” under Splats become “Fried Eggs” under

certain conditionscertain conditions• Domes instead of “Fried Eggs” if Domes instead of “Fried Eggs” if

substrate pre-heatedsubstrate pre-heated

Nylon 11 D-60Nylon 11 D-60“Fried-Egg” SEM Image“Fried-Egg” SEM Image

Preliminary TasksPreliminary Tasks

Construct Heater and InsulationConstruct Heater and InsulationCalibrate HeaterCalibrate HeaterConfigure Set-UpConfigure Set-UpObserve Test-Splats MeltingObserve Test-Splats MeltingDetermine Temperature at Lens of Determine Temperature at Lens of

MicroscopeMicroscope

Substrate Heater RequirementsSubstrate Heater Requirements

Small, Must be fairly compactSmall, Must be fairly compact Insulation to Protect MicroscopeInsulation to Protect MicroscopeClip or Mount to Hold SlidesClip or Mount to Hold SlidesRaised Structure to conform to MicroscopeRaised Structure to conform to MicroscopeVariable Temperature ControlVariable Temperature Control Insulated Electrical ContactsInsulated Electrical Contacts

Substrate HeaterSubstrate Heater

Heater

ThermocoupleReceiver

Thermocouple

Substrate

Test Set-UpTest Set-Up

Variac

Microscope

ThermocoupleReceiver

Heater

Thermocouple

Set-Up for Video ProductionSet-Up for Video Production

Melting Splat VideoMelting Splat Video

Notes from VideoNotes from Video

Flow begins at a recorded temperature Flow begins at a recorded temperature lower than Nylon’s melting temperaturelower than Nylon’s melting temperature

Melting Temperature approximately 180Melting Temperature approximately 180ooCCFlow at approximately 140Flow at approximately 140ooCCThe smaller splats flow before the larger The smaller splats flow before the larger

splatssplatsThe lower features on the eggs flow early The lower features on the eggs flow early

as wellas well

Low Temperature FlowLow Temperature Flow

Second Cycle Melting Temperature Second Cycle Melting Temperature differentdifferent

Experimental error could be a factorExperimental error could be a factorThermocouple cement not thermally Thermocouple cement not thermally

conductive enoughconductive enough

Future ExperimentationFuture Experimentation

Confirm Temperature using Different Confirm Temperature using Different ThermocouplesThermocouples

Confirm Temperature using OvenConfirm Temperature using OvenCompare Results to DSC ResultsCompare Results to DSC ResultsCreate Model of Results in Flow-3DCreate Model of Results in Flow-3DUse Previous Results to Create TimelineUse Previous Results to Create Timeline

AcknowledgmentsAcknowledgments

Dr. Richard KnightDr. Richard KnightGreg FridmanGreg FridmanDustin DossDustin DossVarun GuptaVarun Gupta