MICROSTRUCTURE AND WEAR RESISTANCE OF Ti/TiN MULTILAYER FILMS DEPOSITED BY MAGNETRON SPUTTERING
Wenfang CUI(),Dong CAO,Gaowu QIN
Key Laboratory for Anisotropy and Texture of Materials (Ministry of Education), Northeastern University, Shenyang 110819
Cite this article:
Wenfang CUI,Dong CAO,Gaowu QIN. MICROSTRUCTURE AND WEAR RESISTANCE OF Ti/TiN MULTILAYER FILMS DEPOSITED BY MAGNETRON SPUTTERING. Acta Metall Sin, 2015, 51(12): 1531-1537.
Ti and Ti alloys with low elastic modulus, good mechanical properties and biocompatibility have been widely used for dental implant, arthroplasty and internal fixation material in spinal fusion. But the poor wear resistance of Ti and Ti alloys generally results in the aseptic loosening of the implants. TiN coating has good chemical stability and biocompatibility in physiological environment and plays an important role in improving the corrosion wear performance of Ti and Ti alloys. However, the adhesion strength of TiN film prepared by traditional technologies does not meet the requirement of long service life of the implants. In this work, the alternating Ti/TiN multilayer films were prepared by magnetron sputtering technology with constant Ti layer thickness and varying TiN layer thickness. The cycling periods were designed to be 1, 3, 6, 9, and 12. The total depositing time was 185 min. The main aims of this investigation were to clarify the effects of the cycling periods on the surface morphologies, hardness, bonding strength, friction and abrasion behavior in simulated body fluid of Ti/TiN multilayer films. The results show that the total thickness of Ti/TiN multilayer film is in the range of 5.5~6.0 mm. (111)TiN preferred orientation is found in TiN monolayer film, and (002)TiN preferred orientation is found in Ti/TiN multilayer films. In comparison with TiN monolayer film, Ti/TiN multilayer films exhibit lower surface roughness, higher hardness, bonding strength and wear resistance. The strengthening and toughening of Ti/TiN multilayer films result from the refinement of columnar crystals and interface coherent effect between Ti and TiN layer. The increase of cycling period decreases the hardness of Ti/TiN multilayer film, but is beneficial to enhancing the bonding strength to the substrate. The rupture and exfoliation of thin TiN layer at outer surface promote the abrasive wear and oxidation wear. At the condition of layer thickness ratio 30 for TiN and Ti and 3 cyc, the Ti/TiN multilayer film has good combined mechanical properties. Hardness is 15.8 GPa, adhesion strength is 50 N, coefficient of friction is 0.35, and volume wear rate in Hank's solution is less than 4.0×10-6 mm3/ (Nm).
Fig.1 XRD spectra of TiN monolayer film and Ti/TiN mutilayer films at various cycles
Fig.2 SEM images of TiN columnar crystals in TiN monolayer film (a) and Ti/TiN multilayer film at 3 cyc (b)
Fig.3 FE-SEM images of surfaces of TiN monolayer film (a) and Ti/TiN multilayer film at 3 cyc (b), cross-section of Ti/TiN multilayer films at 3 cyc (c) and 9 cyc (d)
Cycle / cyc
tTi / min
tTiN / min
dTi / nm
dTiN / nm
dTiN/dTi
1
10
175
150
5632
47
3
5
55
60
1770
30
6
5
25
60
805
13
9
5
15
60
483
8
12
5
10
60
322
5
Table 1 Deposition times and thicknesses of Ti and TiN layers in TiN monolayer film and Ti/TiN multilayer film at various cycles
Fig.4 Coefficient of friction vs time plots of TiN monolayer and Ti/TiN multilayer films in Hank's solution
Cycle / cyc
H0.025 / GPa
Fc / N
1
10.8
47
3
15.8
50
6
14.3
87
9
11.2
70
12
13.3
78
Table 2 Hardness and bonding force of Ti/TiN multilayer films at different cycles
Fig.5 Morphologies of worn trails of TiN monolayer and Ti/TiN multilayer films in Hank's solution at 1 cyc (a), 3 cyc (b), 6 cyc (c), 9 cyc (d) (Arrow in Fig.5d indicates exfoliation of TiN layer at outer surface)
[1]
Huang H H, Hsua C H, Pana S J, Heb J L, Chen C C, Lee T L. Appl Surf Sci, 2005; 244: 252
[2]
Cheng Y, Zheng Y F. Surf Coat Technol, 2007; 201: 6869
[3]
Jeong Y H, Lee C H, Chung C H, Son M K, Choe H C. Surf Coat Technol, 2014; 243: 71
[4]
Zalnezhad E, Sarhan A A D, Hamdi M. Mater Sci Eng, 2013; A559: 436
[5]
Zhang X H, Liu D X. Trans Nonferrous Met Soc China, 2009; 19: 557
[6]
Yu X, Wang C B, Liu Y, Yu D Y. Acta Metall Sin, 2006; 42: 662
[6]
(于 翔, 王成彪, 刘 阳, 于德洋. 金属学报, 2006; 42: 662)
[7]
Liu C L, Lin G Q, Yang D Z, Qi M. Surf Coat Technol, 2006; 200: 4011
[8]
Cheng Y, Zheng Y F. Mater Lett, 2006; 60: 2243
[9]
Shao A L, Cheng Y, Zhou Y, Li M, Xi T F, Zheng Y F, Wei S C, Zhang D Y. Surf Coat Technol, 2013; 228: S257
[10]
Liu T W, Dong C, Wu S, Tang K, Wang J Y, Jia J P. Surf Coat Technol, 2007; 201: 6737
[11]
Shao H H, Peng Y T, Jiang X Y, Liu X L, Chen C, Zhu Z H. Funct Mater, 2014; 45: 14145
