Effect of Silicon, Titanium, and Zirconium Ion Implantation on NiTi Biocompatibility

Table 2

Doping element concentration in the ion-implanted surface layers and average surface roughness (roughness height parameter) of the NiTi specimens.

Type of treatment	Specimen marking	Ion type, fluence	Doping (implanted) concentration, at. %	Average roughness (roughness height parameter) 𝑅𝑎, μm
A	NiTi-A	Unimplanted	—	0.972
B	NiTi-B		—	0.047–0.061
G	NiTi-AG,	Zr,	>0.2	0.860–0.940
	NiTi-BG	𝐷1 = 2 × 10^17 cm^−2		0.025–0.041
H	NiTi-AH,	Ti,	>0.3	0.936–1.272
	NiTi-BH	𝐷2 = 2 × 10^17 cm^−2	(relative to its concentration before irradiation)	0.026–0.035
J	NiTi-AJ,	Si,	>0.58	0.892–0.921
	NiTi-BJ	𝐷3 = 2 × 10^17 cm^−2		0.033–0.039