1Surface Modification of Metals
by Using UN-bundled CNTs via
Interface Control

2Tensile strength; 10～60 GPa
Young’s modulus; ~1 TPa

Multi-wall CNT

c.f Carbon steel
Tensile strength; 0.4～1.5 GPa
Young’s modulus; 0.21 TPa3Bundled CNTs

“Materials Defects”

4Un-bundled CNTs
dispersion

Drying

Metal powder
coated with CNTs

Network-structured CNTs on powder

B. Fugetsu, W. Han, N. Endo, T. Okuhara:
Chemistry Letter, 34, 9 (2005) 1218-1219.

5

6TEM observation - Al+4%GNP**GNP; Graphene nanoplate
B. Chen, K. Kondoh, H. Imai, J. Umeda, M. Takahashi: Simultaneously enhancing strength and ductility of carbon
nanotube/aluminum composites by improving bonding conditions, Scripta Materialia, 113 (2016)158-162.

7Dipping

Drying andHeat treatment

Un-bundled CNTs
dispersion

Network-structured CNTs film on Ti plate

J. Umeda et al., Applied Surface
Science, 357 (2015) 721–727.

8Textile using CNTs coated yarns
B. Fugetsu, E. Akiba, M. Hachiya, M. Endo, Carbon, 47 (2009) 527-530.

9Network-structured CNTs film on Ti plate

10Intensity (a.u.)

G+ band Heat treatment caused
higher intensity ratio;➟ Smaller defects in CNTs
and crystallization
RGBD band

Raman shift (cm-1)

CNT film on Ti plate(annealed at 1123 K)

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J. Umeda, B. Fugetsu, E. Nishida, H. Miyaji, K. Kondoh:
Friction behavior of network-structured CNT coating onpure titanium plate, Applied Surface Science, 357 (2015)
721-727.

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 Further TiC formation with increase in H.T temperature Carbon atoms solution intoα-Ti increasing lattice in c-axis

J. Umeda, B. Fugetsu, E. Nishida, H. Miyaji, K. Kondoh:
Friction behavior of network-structured CNT coating on
pure titanium plate, Applied Surface Science, 357 (2015)
721-727.

13(a) 973 KCSurface
Ti

Carbon Content (at.%)50
CNTs film coated Ti
plate after annealing40

at 973 K
at 1123 K

30
201000.0Ti Plate(b) 1123 K

1μm

0.5
1.0
1.5
2.0
Depth from Ti plate surface, d/µm

SurfaceCTi

Ti plate

1μm

参考文献４を示す！
H. Okamoto: Phase Diagrams for Binary Alloys,
ASM International (2010).

14(b)

 TiC thin interlayer having
strong metallurgical bondto both CNTs & Ti plate

Measurement
D1= 0.2520 nm
D2= 0.2160 nm
FAI= 54.0°
PDF card: TiC-fcc
D1= 0.2493 nm
D2= 0.2159 nm
FAI= 54.74°

15 Hard TiC thin interlayer
formation near interface inTi plate Carbon solution hardening
effect near interface
 Residual stress at interface
by difference in thermal coef.
between Ti and TiC

16Load
F=100gf

SUS304 ball

Ti plate with CNTs
coating film

SUS304 ball(φ; 4.7mm)
Rotating speed, v = 31.4 mm/s
Test time, t = 3.6 ks (1 hr)
Total sliding distance, L =113m
No lubricant (in air/dry condition)

Ti plateRotating

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Average friction coefficient, μ0(a) Ti with no coating; μ0 = 0.95

μ0 = 0.34(c) 1123 K annealed; μ0 = 0.19(b) 973 K annealed;

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19

 Ti plate surface damages
due to “abrasive” wear(a) original

 CNTs films effective for“mild ” sliding condition(c) CNTs film (1123K H.T)

20(a) As-received Ti plate (original)(b) CNTs film after 973 K annealingWear debris
from SUS304

at.%

TiFeCr

at.%

TiCFe

Cr01

89.94

7.45

2.6101

55.49

43.62

0.70

0.1902

70.65

22.47

6.8802

53.24

46.76

0.00

0.00

03

99.41

0.59

003

93.69

6.31

0.00

0.00

№ 1&2; Wear debris from SUS304№ 3 ; Ti matrix№ 1&2; CNTs film remained on Ti№ 3 ; Ti matrix with no CNT film

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 Network-structured CNTs coated on pure Ti plate showed a low &stable friction coefficient compared to Ti plate with no coating film.
 CNTs coating film having two important roles; [1] Self-lubrication & bearing effects to reduce friction coefficient [2] Carbon solid-solution hardening to improve abrasive wear
 Secondary heat treatment caused TiC thin interlayer formation atinterface between Ti plate surface & CNTs film, and resulted instrong bonding strength effective for improvement of sliding wear
resistance (mild wear condition).
 In case of as-received raw Ti plate, seizure wear mainly occurred,and caused wear debris from SUS304 counterpart material.

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