ADVANCEMENTS IN SURFACE ENGINEERING PROCESSES

1. ADVANCEMENTS INSURFACE
ENGINEERING PROCESSES
1
S U R F A C E C O AT IN G

2. SURFACEENGINEERINGPROCESSES:TIMELINE
2
1908 Nitriding
1910 Wire Spray( M U Schoop Switzerland )
1923 Anodizing1924 Hard chrome Plating
1930 Physical Vapor deposition (PVD)
1955 Detonation Gun
1960 Plasma Spray ( Metco NY)
1965 Co2 Laser Cladding
1970 Chemical vapor deposition ( CVD) Widia Germany
1980 High Velocity Oxy Fuel ( HVOF)
1990 Cold Spray ( Russia to NCMS)
2000 High Velocity Air Fuel ( HVAF)
2005 Fibre laser cladding
2003 Cold spray commercial equipment
2017 EHLV(High speed laser spray cladding )

3. GAS NITRIDING
3

4. GAS NITRIDINGPROCESS
4
 Gas Nitriding
 In gas Nitriding the donor is a nitrogen rich gas,
usually ammonia (NH3),
 When ammonia comes into contact with the heated work piece it
dissociates into nitrogen and hydrogen.
 The nitrogen then diffuses onto the surface of the material creating a
nitride layer. This process has existed for nearly a century
 Recent developments have led to a process that can be accurately
controlled. The thickness and phase constitution of the resulting
Nitriding layers can be selected and the process optimized for the
particular properties required.

5. PLASMA NITRIDING
5
Schematic Representation of Plasma Nitriding

6. PLASMA NITRIDINGPROCESS
 Plasma Nitriding, also known as ion
Nitriding, plasma ion Nitriding or glow-discharge
Nitriding, is an industrial surface hardening
treatment for metallic materials.
 In plasma Nitriding, the reactivity of the Nitriding
media is due to the gas in ionized state. In this
technique intense electric fields are used to
generate ionized molecules of the gas around the
surface to be nitrided. Such highly active gas with
ionized molecules is called plasma, naming the
technique. The gas used for plasma Nitriding is
usually pure nitrogen, since no spontaneous
decomposition is needed (as is the case of gas
Nitriding with ammonia).
6

7. APPLICATIONS OF NITRIDING
7
Plasma Ion Nitriding on Gears
Gas Nitride coating on Screws AND GEARS

8. HARDCHROME PLATING
8

9. HARD CHROME PLATING
• Chrome Discovered 1798,, first successful electrolytic
• plating 1856, commercial utilization late 1920’s
•
Advantages
–Resists most chemicals, oxygen, and
moisture in air
– Does not tend to seize,, gall,, or cold weld
– Hard surface typical 62 Rc, 0.003”--0..015”
typical thickness
– Simple technology
– Excellent wear resistance
– Historically relatively inexpensive

10. ISSUES WITH HARD CHROME PLATING
– The process produces large amounts of
hydrogengas in the gas bubbles burst
throwing hexavalentchrome solution into the
air as fine mist.
– Hexavalentchrome is a know carcinogen.
– The process produces large volumes of toxic
waste..
– EPA and OSHA have mandated more
stringent stack emission levels and lowering
of permissible exposure limitsfor workers.
– T
h
i
s results in increased costs and business
risks..

11. ENP
(ELECTROLESSNICKELPLATING)
11

12. ADVANTAGES OF ENP
12
 Even coating on parts surface can be achieved.
 No sophisticated jigs or racks are required.
 There is flexibility in plating volume and thickness.
 The process can plate recesses and blind holes with stable
thickness.
 Chemical replenishment can be monitored automatically.
 Complex filtration method is not required
 Matte, semi-bright or bright finishes can be obtained.

14. APPLICATIONOF ENPCOATING
14
ENP Coated Bolts
Wheel Rims ENP Coated

15. 15

16.  PVD is characterized by a process in which the material
goes from a condensed phase to a vapor phase and then
back to a thin film condensed phase. The most common
PVD processes
are sputtering and evaporation. PVD is used in the
manufacture of items which require thin films for mechanical,
optical, chemical or electronic functions. Examples include
semiconductor devices such as thin film solar panels,
aluminized PET film for food packaging and balloons, and
titanium nitride coated cutting tools for metalworking. Besides
PVD tools for fabrication, special smaller tools (mainly for
scientific purposes) have been developed.
 The source material is unavoidably also deposited on
most other surfaces interior to the vacuum chamber,
including the fixturing used to hold the part
16

17. 17
PVD Coating on Drill Bits & Ornaments

18. 18
Schematic of CVD Coating Process

19. CVD (CHEMICAL VAPOR DEPOSITION)
19
 Chemical vapor deposition (CVD) is
a chemical process used to produce high
quality, high-performance, solid materials.
The process is often used in
the semiconductor industry to produce thin
films.
 In typical CVD, the wafer (substrate) is
exposed to one or more volatile precursors,
which react and/or decompose on the substrate
surface to produce the desired
deposit. Frequently, volatile by-products are
also produced, which are removed by gas
flow through the reaction chamber.

20. APPLICATIONSOF CVD COATING
20
Typical CVD Coating
Equipment
CVD Coated Parts

21. CVD V/SPVD
21

22. 22
HP/HVOF
HVAF
Axial
plasma
Wire
spray
Metco
2E
Cold spray
NCMS
Laser cladding
Cold spray
commercial guns
wire
s

23. 23

24. xtausraxx
Various surface Modification
processes

25. Particle velocity V ~
800- 1200m/sec
Spray dist 6-15 inches –
No
heat transfer to base
D
-- =
3.5
d
Gun-
Flsme/Plasma/HV
OF
Flame Temp
3000-
15000*C
Heated
particles
propelled
Concept and
Schematic of
THERMAL SPRAY
Grit blasted surface
Layer by layer coating builds up

26. 26
Chemical
Composition
Manufacture Method
Particle Shape
Particle Size
Distribution Hall Flow
Apparent Density
Liquid- or Gas-
Fuel Spray Gun
Choice Fuel
Used
Spray
Parameter
Kinetic Energy
Thermal
INPUT MATL/POWDER SPRAY PROCESS / GUN COATING
PROPERTIES
Wear Resistance
Corrosion
Resistance Phase
Composition Bond
strength Hardness
Porosity
Deposition Efficiency

27. PLASMA SPRAYING
• Most versatile process in
terms of range of coatings
•plasma temperature: up to 15000 ºC.
• virtually all existing materials
including ceramics. Flame spray 32
57
0-
500m/sec

28. DETONATION GUN SPRAYING
• Flame temperature: 4000 ºC
•Particle Velocity : 1000 m/Sec.
•Bond Strength: 100 Mpa
28

29. HIGH-VELOCITYOXY FUELSPRAYING (HVOF)
29

30. HVOF
Porosity 0.5-1%
Hardness 1100-1250 HV0.3
Harder coatings are
overstressed
±150-200 HV deviation
4-5 kg/h, 5-10 µm per pass
HVAF
Gas impermeable @50 µm
1200, 1350 or 1600+ HV0.3
Ductile and cavitation resistant
±50-60 HV deviation
15-33+ kg/h, 50 µm per pass

31. HVAF
Jet Kote
Kermetico C6, C7
1700-
2100 °C
DJ 2600
JP 5000
2982 °C
2982 °C
Opt Tc + Axial
↓
Opt heating
Long nozzle
↓
Opt velocity

32. THE RESULT
kermetico.com jrienecker@kermetico.com
Gu
n
Hardness,
HV300
Poro
-sity,
%
Fracture
Tough-
ness
K1C
Ratio
W2C
to
WC
AK 1,326 ± 98 0.3
5.97
±0.7
0
JP
1,289 ±
108
0.6
4.87
±0.6
0.12
JK
1,047 ±
112
1.7
3.01
±0.6
0.7
Source: Wear and corrosion performance of
WC-10Co-4Cr coatings deposited by different
HVOF and HVAF spraying processes
Qun Wang etc., Hunan University, 2013
JP 5000
AK7
Jet Kote

33. EROSIONRATEVS. AN ATTACK ANGLE:
WC-10CO-4CR HVAF COATINGS PERFORM AS A
DUCTILEMATERIAL
Midwest Thermal Spray (MI, USA)
0.000
0.050
0.100
0.150
0.200
0.250
0.300
AK06-HVAF: WC-Co-Cr HVOF MTS: WC-Co-Cr SHS8000, fused
Volume
loss,
mm3/min
Dry erosion rate of hard coatings
Angle 30 deg. Angle 90 deg.

34. UNIFORMITYOF HVAF COATING PROPERTIES:
HARDNESS OF HVOF AND KERMETICO HVAF WC-10CO-4CR COATINGS
(SCHLUMBERGER, UK)
kermetico.com jrienecker@kermetico.com
HVAF
OF
Relative standard
deviation, %
HVAF: 3.9 %
HVOF: 15.7-17.8%

35. KERMETICOHVAF:
YOUR CHOICE OF COST AND QUALITY
kermetico.com jrienecker@kermetico.com
HVAF-E (Economy) – meets HVOF specs
HVAF-B (Balanced) – exceeds HVOF specs
HVAF-U (Ultra) – Coatings beyond the limits
HV spraying = deposition + blasting
Well bonded particles will stay, poor bonded will go away
Higher velocity => more blasting => ↑quality ↑cost

36. 36
Spray Particle Temperature Vs. Wc & W2C Phase CompositionB
HVAF working zone
(1600-1800 C )

37. HVAF COATINGS PERFORM BETTER
THAN HVOF
HVAF tungsten carbide coatings
are harder and stronger than
HVOF ones, yet they are ductile.
These are the reasons why they
resist wear and cavitation
combined. 37

38. Suspension HVOF-spraying

39. 39
Power and aero turbine areas where coatings
are applied. Cold zone and Hot zone and
abradables

40. SEVERESERVICEAPPLICATIONS
40
Plug Valve TC Coating Control Valve Stem-Stellite 6 Coating
Ball Valve TC Coating Mud Rotor TC Coating & Super Polish

41. APPLICATIONSOF HVOF &HVAF INCOATING OF
FRANCIS T
U
R
B
I
N
EHEAD COVER
kermetico.com jrienecker@kermetico.com

42. WC-Co-Cr
1 mm thick
Conveyor Screws

43. ROTOR SHAFT
REPAIR –
CHROME CARBIDE
Repair of turbine casing
Applications of TC Coating in Power Turbines

44. PUMPAND VALVE APPLICATIONS
P u m p a n d v a l v e a p p l i c a t i o n s
C a g e c a r b i d e c o a t e d K n i f e G a t e v a l v e b o d y c a r b i d e
c o a t e d
I m p e l l e r c e r a m i c c o a t e d
S l e e v e c e r a m i c c o a t e d &
G r o u n d
C e r a m i c c o a t e d s l e e v e s
F o r F o o d i n d u s t r y
44
H a r d f a c e d p u m p s l e e v e

45. BRIDLE ROLL
CARBID
E COATING
Application of HVOF Coating- Steel Mill CRM Roll

46. 46
Spray Particle Temperature Vs. Wc & W2C Phase CompositionB
HVAF working zone
(1600-1800 C )

47. 47

48. Compressed
gas
Powder
feeder
Substrate
The gas dynamic cold spray coating is based on the projection of solid powder at
high velocity.
De Laval Nozzle
Principle of cold spray
1. A compressed gas is heated before entering in a DE
Laval Nozzle.
2. The gas is accelerated in the nozzle.
3. Powder is injected in the gas stream and accelerated as
well.
4. The powder reaches velocity up to 1200 m/s.
5. The powder is plastically deformed and the coating is
building up.

49. COLD SPRAYING
• Gas temperature: under the
phase transition temperature ~ 800,1000C
• sprayed materials: pure Al, Zn, Cu, Ni
Alloys : NiCr, Cr- Carbide/NiCr 49

50. Assadi et al., Bonding mechanismin cold gas spraying, Acta
Materialia, 51, 4379-4394, 2003
Bonding mechanism
T. Schmidt et al., From Particle Acceleration to Impact and Bonding in Cold Spraying, Journal of
Thermal Spray Technology, 18, 5-6, 794-808, 2009
Typical surface around the critical velocity
Q. Blochet, Influence of substrate surface roughness on cold-sprayed coating-substrate bond strength in aluminum-
based systems, PhD Thesis, Mines ParisTech, 2015

51. 51

52. Cold spray advantages and limitations
Advantages:
• No powder melting
No phase change
No grain growth
Low heating of the substrate
• No significant impact on the oxide content w.r.t. initial
material
• Powder mixture possible
• Compressive residual stress (fatigue life increase)
• Nozzle geometry can be tuned for a given jet size
• Thick coating
• High deposition rate
Limitations:
• One constituent has to be ductile
• Accessibility to the surface to be coated
• Limited materials for coating as of now

53. 53

54. 54
SPRAYMET
S U R F A C E C O AT IN G

55. 55
Hot Process ( Cladding )
Spray and fuse
Plasma Transferred Arc ( PTA) cladding
Laser Cladding

56. 56
C l e a n t h e s u r f a c e w i t h s o l v e n t s
S h o t b l a s t w i t h s t e e l g r i t s ( D o n o t u s e A l u m i n u , o x i d e g r i t s )
P r e h e a t t h e j o b i n r o t a t i o n t o ~ 2 0 0 d e g ( f l a t j o b s c a n b e s t a t i o n e r y w i t h f i r m
f i x t u r e ) S p r a y t h e a l l o y ( # 4 5 , 5 5 , 6 0 , ) a p p r o x 3 0 0 m i c o r n s t o a v o i d s u r f a c e
o x i d t i o n
I n c r e a s e t h e t e m p o f j o b t o ~ 6 5 0 C w i t h t o r c h a n d w h e n j o b i s h o t s p r a y a g a i n t o b u i l d u p .
F u s e t o t a l t h i c k n e s s ( 1 . 5 m m – 2 m m ) t o g e t h e r w i t h u n i f o r m o r a n g e c o l o r o n j o b . ( 9 0 0 -
1 0 5 0 * C ) A l l o w j o b t o r o t a t e f o r s o m e t i m e t ill o r a n g e c o l o r d i s a p p e a r s . E l s e b e n d w i l l c o m e
i n j o b .
S l o w c o o l t h e j o b b y k e e p i n g i n r o c k w o o l o r v e r m i c u l i t e t ill r o o m t e m p e r a t u r e
A f t e r s p r a y b r i c s a r e k e p t a r o u n d j o b t o c o n t a i n h e a t f o r f a s t e r t o r c h
f u s i o n
B i g j o b s n e e d s t w o o r t h r e e t o r c h e s f o r
f u s i o n .
L o n g j o b s c a n b e g r a d u a l l y f u s e d i n
r o t a t i o n .

57. PLASMA TRANSFEREDARC SPRAYING(PTA)
• Fe, Ni, Co, Cr based alloys,
stainless steels, cermets
•Dilution ~ 2 %
Schematic of PTA

58. 58
Hard Surfacing
PTAW is well suited to apply hard alloys for wear resistance. Stellite,
Colmonoy, Hastelloy, and Tungsten Carbide can all be successfully applied with
PTAW.
Corrosion Resistant Overlays
The localize heat input characteristics of PTAW allow corrosion resistant alloys
to be applied with very little dilution into the base material. PTAW can achieve
subsea chemistry requirements of <5% Fe in as little as 0.040” of overlay
thickness.
Flow Controls
Valve Bores, Gates, Seats, Seat Pockets, Ring Grooves, Valve Stems.
Power Industry
Turbine Blades, Shafts, Bearing Surfaces, etc.

59. Rock Bit Journal Overlayed with
Stellite 6 Crack Free
Typical PTA depositon

60. 60
• virtually all metal alloys,
cermets and ceramics. Dilution
< 1 %
Schematic of Laser Cladding.

61. Laser cladding :
Metallurgical
Bonding
HVOF/HVAF :
Mechanical Bonding
WC+NiCrB
Si
WcCoCR
V low dilution / 100% clear bond line Nil dilution / 90% clear bond line
Laser Cladding VS HVOF/HVAF coatings :
Metallurgically speaking :

62. 62
• Best technique for coating any shape increase life-time of wearing parts.
• Particular dispositions for repairing parts (ideal if the mould of the part no
longer exist or too long time needed for a new fabrication).
• Most suited technique for graded material application.
• Well adapted for near-net-shape manufacturing.(DLAM)
• Low dilution between track and substrate (unlike other welding processes
and strong metallurgical bond.
• Low deformation of the substrate and small heat affected zone (HAZ).
• High cooling rate fine microstructure.
• Built part is free of crack and porosity.
• 100% metallurgical bond line

63. 63
Laser Cladding Head
Co Axial Laser Head

64. 64
Common Base Material Grades Common materials utilized in manufacture of oilfield
MWD/LWDCollars. 17-4PH, INCONEL 718/925,P550,
Duplex Stainless Steel and AISI41XX.
Common Weld Overlay Grades Tungsten carbide/ Nickel-Chrome composite, Nickel
alloy 625/C-276, Cobalt Alloys, Copper alloys and
various other stainless steel grades.
Laser Cladding Applications (Drilling tools) Hard facing of MWD/LWDdrill collars, Stabilizer sleeves,
Wear bands.
Laser Cladding Applications (Engineering) Hardfacing of Guides and rollers for steel works.
Cladding of bearing surfaces on transmission shafts,
pump shafts, drive shafts, hydraulic cylinder rods
Laser Cladding Applications Cladding of thermo wells for chemical process plants
and refineries. Hard facing of wear parts for brick and
clay works,pulp and paper, mining and agriculture
industries.

65. 65
Before Laser Cladding Stabilizer
Rollers
After Laser Cladding
Process on Stabilizer Rollers

66. Laser cladding process
Dilution/distortion negligible
Laser cladded stabilizer
Cladding of Hydraulic Ram &
Piston Guides
Rotor Repair by Laser
Cladding

67. ULTRAHIGHSPEEDLASERCLADDING
(EHLA)
Fraunhofer’s EHLA process has been adopted for applying protective
coatings to hydraulic cylinders for maritime use
Using this technique, coating speeds can reportedly be accelerated from
0.5-2 m per minute to as many as 5 m per minute. The use of EHLA also
reduces minimum layer thickness from 500 μm to 25-250 μm, and layers
are reported to be smoother, with roughness reduced to a tenth of typical
values for Laser Material Deposition.

68. ⯈ Hard trivalent chrome
⯈ THERMAL SPRAY
⯈ Plasma spray ceramic
⯈ High velocity oxy-fuel (HVOF)/High velocity air-fueled (HVAF)
⯈ Twin wire arc spray ( low cost high C- High Cr )
⯈ PLATING ALTERNATIVES TO HEXAVALENT CHROME
⯈ Electro less nickel plating/ Electroless nickel with boron / Teflon composites
⯈ Electrodeposited Nano crystalline cobalt-phosphorus coatings
⯈ Nickel-cobalt alloy coatings
⯈ OTHERS
⯈ Explosive bonding
⯈ Laser cladding
⯈ Physical vapor deposition (PVD)
⯈ Electro-spark deposition
ALTERNATIVES TO HARD CHROME
PLATING SOUGHT

69. COMPARISON OF HARD CHROME PLATING TO HVOF
⯈ Micro cracks Micro porosity max 1 % (No through passage)
Superior Corrosion Resistance :Hard chrome plating however contains micro-
cracks within its structure which forms a weakness against corrosion versus
thermal spray, as shown in the picture below.
Hard chrome plate
Chrome Plating HVOF/HVAF Spray

70. Results form Komatsu paper 2016

71. PROCESS BENEFITS :
HVOF VS. HARD CHROME
Specifications Hard Chrome Plating HVOF
Surface Hardness 62 Rc 71 Rc
Time required to coat
Komatsu 830E first
stage
7 hours (0.002” per
hour to get
0.007”/side
1 hour (12 lbs at 12
lbs/hour to get
0.007”/side
Work Piece Temp 145 F 300-350F
Post Plate H2 Relief 275-425 F for 2-4 hours Not required
Desired Surface Finish 0.4-0.8 um
16-32u in 2-6 u in

72. BOSCH REXROTHOEM CYLINDERS
Endutorq 1000 laser cladded Endutorq 2000 HVOF coated

73. EATON USA
Eatonite anti-corrosion laser
cladding is a high performance,
field repairable, 3rd party certified,
hydraulic cylinder rod coating
designed for the most demanding
fresh and salt water applications
and harshest operating
environments. Eatonite anti-
corrosion laser cladding extends
the life of hydraulic cylinders and
reduces costs of unplanned
maintenance and equipment
downtime.

74. SUMMATION
• Hard chrome has the COST advantage that it is a single
material and deposition method that can be used for a wide
variety of applications
• HVOF/HVAF is a single technology, with a wide variety of
materials that can be used to achieve the right combination
of properties for many purposes. Butmechanical Bonding
• COLD SPRAY is a emerging technology presently limited to
SOFTmaterials
• Laser Cladding is now a approved and widely used
depostion process with low heat input and dilution. Replacing
hard chrome in many applications where impact is involeved