538
V. S. Simi et al.
Fig. 19 FESEM images of TNT (a) and TNT + PN (b) (top view) inset water contact angle,
(c) and (d) 3D images at higher magnification obtained from FESEM image and 2D profile of the
nanotubes (e) and (f) (Republished with permission of the Royal Society of Chemistry, from Mohan
et al. [120])
Mohan et al. [120] reported the effect of plasma nitriding on the structure and
biocompatibility of self-organised TiO 2 nanotubes on Ti–6Al–7Nb alloy. Figure 19a
shows the FESEM image of TNT obtained after anodisation of Ti-6Al-7Nb for 1 h at
20 V. The FESEM image of TNT plasma nitrided at 800 °C (TNT +PN) was shown
in Fig. 19b. The 3D image of the TNT and TNT + PN obtained from FESEM image,
respectively are given in Fig. 19c and d. The 3D images evidenced the formation of
highly ordered tubes on Ti-6Al-7Nb. Similarly, Fig. 19e and f shows the 2D profile
of the TNT and TNT + PN obtained respectively from FESEM images. FESEM
images of the TNT and TNT + PN revealed that the arrays have very regular and
vertically aligned tube structure. For TNT and TNT + PN samples, the nanotubes
have diameters of approximately 100 and 80 nm and an average inter-tube distance
of approximately 30 and 35 nm respectively as demonstrated in figure. The height
of the TNT is approximately 250 nm. These results indicate that there is no much
change in tubular dimensions after nitriding.
Nanohardness measurement was carried out on substrate, plasma nitrided
substrate, TNT and TNT + PN samples at 0.5 mN load to study the effect of nitriding
in improving the hardness of the specimens Five indentations were taken at different
sites to check the uniformity of the coating hardness. Figure 20a and b shows the
FESEM images of samples after NHT on TNT and TNT + PN samples respectively.
The 3D image of the TiO 2 nano tube array generated from FESEM image for the
same are shown in Fig. 20c and d. Similarly, Fig. 20e and f shows the 2D profile
of the nano indentation on TiO 2 nanotube array obtained from FESEM images after
NHT. After plasma nitriding, the hardness ofTi-6Al-7Nb has increased to 15.5 GPa
than the substrate value of 9.2 GPa. Similarly, the hardness of the TNT and TNT
+ PN was 1.4 and 2.2 GPa, respectively. The nanoindentation studies showed that
the mechanical properties of the TNT + PN are better than that of TNT. Nitriding
V. S. Simi et al.
Fig. 19 FESEM images of TNT (a) and TNT + PN (b) (top view) inset water contact angle,
(c) and (d) 3D images at higher magnification obtained from FESEM image and 2D profile of the
nanotubes (e) and (f) (Republished with permission of the Royal Society of Chemistry, from Mohan
et al. [120])
Mohan et al. [120] reported the effect of plasma nitriding on the structure and
biocompatibility of self-organised TiO 2 nanotubes on Ti–6Al–7Nb alloy. Figure 19a
shows the FESEM image of TNT obtained after anodisation of Ti-6Al-7Nb for 1 h at
20 V. The FESEM image of TNT plasma nitrided at 800 °C (TNT +PN) was shown
in Fig. 19b. The 3D image of the TNT and TNT + PN obtained from FESEM image,
respectively are given in Fig. 19c and d. The 3D images evidenced the formation of
highly ordered tubes on Ti-6Al-7Nb. Similarly, Fig. 19e and f shows the 2D profile
of the TNT and TNT + PN obtained respectively from FESEM images. FESEM
images of the TNT and TNT + PN revealed that the arrays have very regular and
vertically aligned tube structure. For TNT and TNT + PN samples, the nanotubes
have diameters of approximately 100 and 80 nm and an average inter-tube distance
of approximately 30 and 35 nm respectively as demonstrated in figure. The height
of the TNT is approximately 250 nm. These results indicate that there is no much
change in tubular dimensions after nitriding.
Nanohardness measurement was carried out on substrate, plasma nitrided
substrate, TNT and TNT + PN samples at 0.5 mN load to study the effect of nitriding
in improving the hardness of the specimens Five indentations were taken at different
sites to check the uniformity of the coating hardness. Figure 20a and b shows the
FESEM images of samples after NHT on TNT and TNT + PN samples respectively.
The 3D image of the TiO 2 nano tube array generated from FESEM image for the
same are shown in Fig. 20c and d. Similarly, Fig. 20e and f shows the 2D profile
of the nano indentation on TiO 2 nanotube array obtained from FESEM images after
NHT. After plasma nitriding, the hardness ofTi-6Al-7Nb has increased to 15.5 GPa
than the substrate value of 9.2 GPa. Similarly, the hardness of the TNT and TNT
+ PN was 1.4 and 2.2 GPa, respectively. The nanoindentation studies showed that
the mechanical properties of the TNT + PN are better than that of TNT. Nitriding