38
X. Sun et al.
Fig. 3.8 Roughness measurement after electropolishing
Table 3.3 Surface chemical composition and content
Material element
Ti
Ni
Cl 2 p
C 1 s
O 1 s
TiO 2
Nitinol tube
43.86
56.14
0
0
0
0
Stent after laser cutting
47.29
52.71
0
0
0
0
Stent after electropolishing
0.7
38.70
0.97
13.36
9
37.27
water to form stable titanium dioxide, as shown in Eqs. (3.3) and (3.4). Titanium
dioxide layer plays an important role in the biocompatibility of the stents [16], so
the biocompatibility of the stents after electropolishing has been greatly improved.
T iCl 4 (l) + HO − CH 2 CH 2 − OHTi(O − CH 2 CH 2 − OH) 4 (l) + 4H
+
+ 4Cl
−
,
(3.3)
Ti(O − CH 2 CH 2 − OH) 4 (l) + 2H 2 OTiO 2 (s) + 4HO − CH 2 CH 2 − OH. (3.4)
X. Sun et al.
Fig. 3.8 Roughness measurement after electropolishing
Table 3.3 Surface chemical composition and content
Material element
Ti
Ni
Cl 2 p
C 1 s
O 1 s
TiO 2
Nitinol tube
43.86
56.14
0
0
0
0
Stent after laser cutting
47.29
52.71
0
0
0
0
Stent after electropolishing
0.7
38.70
0.97
13.36
9
37.27
water to form stable titanium dioxide, as shown in Eqs. (3.3) and (3.4). Titanium
dioxide layer plays an important role in the biocompatibility of the stents [16], so
the biocompatibility of the stents after electropolishing has been greatly improved.
T iCl 4 (l) + HO − CH 2 CH 2 − OHTi(O − CH 2 CH 2 − OH) 4 (l) + 4H
+
+ 4Cl
−
,
(3.3)
Ti(O − CH 2 CH 2 − OH) 4 (l) + 2H 2 OTiO 2 (s) + 4HO − CH 2 CH 2 − OH. (3.4)