Nano HVOF coaitngs for Hydro turbine and under water components to resit silt erosion and cavitation

1. HYDROKOTE – N3HYDROKOTE – N3
HVOF CARBIDE COATINGHVOF CARBIDE COATING
For Hydro turbine componentsFor Hydro turbine components
Spraymet Surface Technologies Pvt LtdSpraymet Surface Technologies Pvt Ltd
Bangalore and PuneBangalore and Pune
spraymet@gmail.comspraymet@gmail.com

2. Hydro turbine tribologyHydro turbine tribology
Hydro turbine and under water parts undergo severe :Hydro turbine and under water parts undergo severe :
SILT EROSION AND CAVITATIONSILT EROSION AND CAVITATION
To resist these severe conditions we can adopt any or combinationTo resist these severe conditions we can adopt any or combination
following technologiesfollowing technologies
• Higher grade materialHigher grade material
• Weld HardfacingWeld Hardfacing
• NitridingNitriding
• HVOF carbide coatingHVOF carbide coating
• Poly Urethane type coatingsPoly Urethane type coatings

3. COMMON SURFACE TREATMENT METHODSCOMMON SURFACE TREATMENT METHODS
VS HVOF in Hydro turbine applicationsVS HVOF in Hydro turbine applications
Plating – Hard chrome,Anodising, ENP etcPlating – Hard chrome,Anodising, ENP etc
( bath type proocess and non environment firendly)( bath type proocess and non environment firendly)
Weld Cladding – MMAW, TIG,Weld Cladding – MMAW, TIG,
( hot Process and involves lot of distortion)( hot Process and involves lot of distortion)
Gas Nitriding /Plasma nitridingGas Nitriding /Plasma nitriding
(needs nitradable steel and huge furnace size and can not be done in-situ)(needs nitradable steel and huge furnace size and can not be done in-situ)
Physical Vapor Deposition TechnologyPhysical Vapor Deposition Technology
( Not suitable for sever silt condition and huge furnace size and can not be done in-situ) ( Not suitable for sever silt condition and huge furnace size and can not be done in-situ)
Thermal Spraying – HVOF : Popular option now.Thermal Spraying – HVOF : Popular option now.
( High Hardness ( Rc 72), Thcik coatings ( 500 mic and In-situ capability( High Hardness ( Rc 72), Thcik coatings ( 500 mic and In-situ capability))

4. FacilityFacility
HVOF Spray RoomHVOF Spray Room Robotic HP/HVOFRobotic HP/HVOF

5. HVOF (High Velocity Oxygen Fuel) spray processHVOF (High Velocity Oxygen Fuel) spray process
The HP/HVOF spray process uses the high pressure (8-The HP/HVOF spray process uses the high pressure (8-
10bar) combustion pressure of Oxygen and Fuel to10bar) combustion pressure of Oxygen and Fuel to
generate 3500 deg C heat and Mach 3 velocitygenerate 3500 deg C heat and Mach 3 velocity
The process creates a very high velocity >1200m/sThe process creates a very high velocity >1200m/s
Propel the particles at supersonic speeds ~800- 1200m/sPropel the particles at supersonic speeds ~800- 1200m/s
High impact force results in Bond strength >10000PSI andHigh impact force results in Bond strength >10000PSI and
porosity of less than 1 %porosity of less than 1 % ( almost dense like wrought material )( almost dense like wrought material )
SPRAYMET
SURFACECOATING
7-8 schock diamonds in supersonioc flame
Sharp Hi velocity flame > 1200m/sec

6. PROCESS INSIGHTPROCESS INSIGHT
Process FlowProcess Flow Coating FormationCoating Formation

7. Comparison of Thermal spray ProcessesComparison of Thermal spray Processes

8. HVOF carbide coating
Typical micrographTypical micrograph
Hardness 72 RC, 1 % porosity, > 10000PSI adhesion strengthHardness 72 RC, 1 % porosity, > 10000PSI adhesion strength

9. Evaluation of coatingsEvaluation of coatings
Micro Hardness HV 0.3 E 389Micro Hardness HV 0.3 E 389
Porosity ASTM 2109Porosity ASTM 2109
Micrograph 400X voids, oxides etcMicrograph 400X voids, oxides etc
Bond strength ASTM C 633Bond strength ASTM C 633
Bend testBend test
Salt Spray Test ASTM B 117Salt Spray Test ASTM B 117
Surface rough nessSurface rough ness

10. Reports and DocumentationReports and Documentation
Powder compositionPowder composition ( WcCoCr 86/10/4 )( WcCoCr 86/10/4 )
Coating Hardness HV 0.3( On coupon)Coating Hardness HV 0.3( On coupon)
Bond test at IMR SingaporeBond test at IMR Singapore
Bend test ( at request ) ASTM B 571Bend test ( at request ) ASTM B 571
Porosity test at NABL LabPorosity test at NABL Lab
Silt Erosion test ( at request)Silt Erosion test ( at request)

11. Bend Test ReportBend Test Report

12. Adhesion Strength report as perAdhesion Strength report as per
ASTM C 633ASTM C 633

13. Porocity and Hardness ReportsPorocity and Hardness Reports

14.
HVOF COATING OPTION FOR HARD Hydroturbine
Carbides Process Hardness Thickness Notes
Tungsten
carbide/Cobalt
88/12 or 83/17
HVOF 1100 to 1350
HV 0.3
150-200 to
Microns
Dense and hard Coatings
wear, Applications for
temperatures up to 450
Deg C
Tungsten
carbide/Cobalt
/Chromium
86/10/4
HVOF 1100 HV to
1200 Hv 0.3
150-200 to
Microns
Improved corrosion
protection over
WC-Co and WC-Ni.
Carbide Blends
*** Tungsten
carbide+NiCrBSi
50/50 , 65/35
HVOF 1000 to 1300
Hv 0.3
150-200 to
Microns
A blend of Tungsten
carbide and NiCrBSi for
fretting wear, erosion,
abrasion
Chrome carbide
/NiCr (75/25)
HVOF 850-1100 HV 150-200 to
Microns
Good and lower cost
replacement for
Hardchrome temp
resistance 850 C
SPRAYMET
HYDROKOTE –N3
NANO CARBIDE
WITH HIGHER
HARDNESS
HP/HVOF or
HVAF
> 1200
-1400HV
500 mic Very dense and
hard coatings
easily finsihable
to 0.4 ra

15. SPRAYMET HYDROKOTE -N3SPRAYMET HYDROKOTE -N3
nano carbide coating for higher performancenano carbide coating for higher performance
Advantages : over traditional HVOF carbideAdvantages : over traditional HVOF carbide
Nano carbides provide densest coatingNano carbides provide densest coating
Porosity < 0.6 %Porosity < 0.6 %
Hardness over 1300 HVHardness over 1300 HV
Option of Super finishsihing to 0.2 RaOption of Super finishsihing to 0.2 Ra
Fully sealed with Phenolic sealerFully sealed with Phenolic sealer

16. Hardness ComparisonHardness Comparison

17. Abrasion ComparisonAbrasion Comparison

18. Salt Spray test results of Wc/Co/Cr HVOF coatingSalt Spray test results of Wc/Co/Cr HVOF coating
HVOF coatings sustain > 2000 Hrs ( sub sea applicaions )HVOF coatings sustain > 2000 Hrs ( sub sea applicaions )
vs Hard Chrome 200 hrsvs Hard Chrome 200 hrs

19. Pelton turbine HVOF sprayPelton turbine HVOF spray
stagesstages
As received turbine Grit Blasted surface
HVOF coating in progress HVOF carbide 300/500mic thick

21. S P R A Y M E TS P R A Y M E T
ContactContact
Bangalore :Bangalore :
A 413, 9A 413, 9thth
main, 2main, 2ndnd
stage, Peenya Indl Area,Bangalore 560058,stage, Peenya Indl Area,Bangalore 560058,
Tel/Fax ; 080- 28364565 E mail :Tel/Fax ; 080- 28364565 E mail : spraymet@gmail.comspraymet@gmail.com ,,
Pune : Plot 244, Sector 7 , PCNTDA, MIDC Bhosari , PunePune : Plot 244, Sector 7 , PCNTDA, MIDC Bhosari , Pune
Tel : 8149046272Tel : 8149046272
E mail : spraymetpune@gmail.comE mail : spraymetpune@gmail.com
Thank youThank you
SPRASURFACECOATING