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Effect of nickel salts on the wear properties of electrodeposited nanocrystalline Ni-Co coating. Chao Ma Supervised by : Dr. Shuncai Wang Prof. Frank Walsh. Outline. 1. INTRODUCTION . 5. FUTURE WORK. 2. METHODOLOGIES . 3. RESULTS AND DISCUSSIONS . - PowerPoint PPT Presentation
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Effect of nickel salts on the wear properties of electrodeposited nanocrystalline Ni-Co coating
Chao MaSupervised by : Dr. Shuncai Wang Prof. Frank Walsh
LOGOOutline
1. INTRODUCTION
2. METHODOLOGIES
3. RESULTS AND DISCUSSIONS
4. CONCLUSION
5. FUTURE WORK
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Cr(VI)Hard Cr Electrodeposition
IntroductionNanocrystalline Wear and Corrosion Resistant Coatingsas an alternative to hard Cr deposits
Eletrodeposition is a low-cost and versatile technique to form the nano-crystalline coatings, which exhibit unique properties derived from their large number of grain boundaries compared to coarse-grained surface.
www.newworldencyclopedia.org/entry/Electroplating http://jolisfukyu.tokai-sc.jaea.go.jp/fukyu/tayu/ACT02E/06/0603.htm
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Good wear resistanceNanocrystallineNi-Co coating
Introduction
High hardness
Good corrosion resistance
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Electrochemical Corrosion Behavior Crystal Morphology
&Microstructure
Hardness
Process of Electroplating
Introduction
Tribology Properties
THE EFFECT OF NICKEL SALTS
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Microstructure analysis
2
Electroplating
1
METHODOLOGIES
SEM&EDS, TEM, XRDg/l SS1 SS2 SS3 SS4
NiSO4•6H2O
200 200 - 50
NiCl2•6H2O
- 50 200 200
CoSO4 H2O
100 100 100 100
Additives
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Hardnesstest
Tribology test
3
METHODOLOGIES
4
Wear volume was measured by an optical 3D surface profilometer
Friction and wear behaviour were tested on a reciprocating pin-on-disc TE-77 tribometer
LOGORESULTS AND DISCUSSIONS
0
50000
100000
150000
200000
250000
35 40 45 50 55 60 65 70 75
SS1 SS2
SS3 SS4
SS3
SS4
SS2
SS1
XRD
Mixed structure of fcc and hcpwith (111)α preferred orientation
Independent of the nickel salts
The finest grain size (5-10nm) is obtained from the coating prepared by NiSO4 electrolyte.
TEMNiCl2 electrolyte
NiSO4 electrolyte
LOGORESULTS AND DISCUSSIONS
SEM MorphologiesNiSO4 electrolyte
Adding NiCl2
fine granular grains lens shape
NiSO4-dominant electrolyte
LOGORESULTS AND DISCUSSIONS
50 100 150 200 250 300 350 400 4500
0.10.20.30.40.50.60.70.8
SS1 SS2
Time / s
Fric
tion
Coef
f
The lens morphology significantly reduces the microhardness, which leads to the increasing coefficient of friction and wear rate.
Tribology test
NiSO4-dominant electrolyte
Hardnesskg/mm2
503 352
Wear rate10-4 mm3/Nm
K= V/SFV is the wear volume (in mm3)S the total sliding distance (in m) F is the normal load (in N)2.34 5.32
NiSO4 electrolyte
LOGORESULTS AND DISCUSSIONS
SEM Morphologies
NiCl2 electrolyte
Adding NiSO4
pyramidal crystals
NiCl2-dominant electrolyte
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350 370 390 410 430 450 470 490 510012345678
Wear rate
Microhardness (kg/mm2)
Wea
r ra
te (1
0-4
mm
3/N
m )
Friction of coeffi-cient
Tribology test
Hardnesskg/mm2
477 469
Wear rate10-4 mm3/Nm
4.95 7.03
RESULTS AND DISCUSSIONS
Decrease of internal stress
50 100 150 200 250 300 3500
0.10.20.30.40.50.60.70.80.9
SS3SS4
Time / s
Fric
tion
Coef
f
Variations of wear rate as a function of hardness
Debris
Traditional Archard’s LawQ=KLN/H
NiCl2 electrolyte NiCl2-dominant electrolyte
LOGOCONCLUSION
Wear properties of electrodeposited nanocrystalline Ni-Co coatings are affected by different kind of nickel salts in electrolyte
The corresponding changes of the morphology and the crystal may lead to different wear mechanisms
The coating formed from NiSO4 electrolyte performs better tribological behaviour, which can be attributed to the finest grain size and the fine granular grain morphology. NiCl2 can increase the internal stress.
LOGOFUTURE WORK
Electrodeposited Ni-Co coating
Nucleation and growth of nanocrystalline
Morphology
Grain size Phase structure
Hardness, Surface roughness, Adhesive interaction
Internal stress
Friction Wear
Relationship of processing-microstructure and crystal morphology- tribological properties
LOGOUK-China Summer School on Tribology & Surface Engineering
23-25th August 2010 Chilworth Manor Hotel (2 mile away from the University of Southampton)
Sponsored by RCUK –Research Councils UK
General Chair (UK and China): Prof. R.J.K. Wood, Vice President of the International Tribology Council Prof. Weimin Liu, Vice President of the Chinese Tribology Institute
CONTACT DETAILS OF ORGANIZING COMMITTEE: Dr. S.C. Wang E-mail: [email protected]. +44-(0)23-80594638
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