Apatite formation on electrochemically modified surface of hafnium metal in simulated body environment

Figures & data

Table 1. F content of the samples after various treatments

Sample	F/(F + O+ Hf)
SA	0
FA20	0.179 ± 0.00721
FC	0.165 ± 0.0207
FS	0

Table 2. Elemental composition of the apatite formed on FA20

Element	Atomic ratio (%)
O	27.1
F	0.14
P	25.8
Ca	46.4
Hf	0.58

Figure 1. FE-SEM photograph of Hf substrate anodically polarized in NH₄F solution.

Figure 2. SEM photographs of SA and FA20 before and after soaking in SBF. Soaking time is 7 days for SA and 8 days for FA20.

Figure 3. TF-XRD patterns of SA and FA20 before and after soaking in SBF. Soaking time is 7 days for SA and 8 days for FA20.

Figure 4. SEM photographs and TF-XRD patterns of FA60 before and after soaking in SBF for 3 days.

Figure 5. SEM photographs of Hf substrates after cathodic polarization in NH₄F solution and heat treatment, followed by soaking in SBF for 8 days.

Figure 6. TF-XRD patterns of Hf substrates after cathodic polarization in NH₄F solution and heat treatment, followed by soaking in SBF for 8 days.

Figure 7. SEM photographs of Hf substrates after soaking in NH₄F solution and heat treatment, followed by soaking in SBF for 7 days.

Figure 8. TF-XRD patterns of Hf substrates after soaking in NH₄F solution and heat treatment, followed by soaking in SBF for 7 days.

Table 3. Contact angle using ultrapure water and surface energy of the samples

Sample	Contact angle/°	Surface energy γs/mJ·m^−2
SA	32.3 ± 0.4	67.7
FA20	4.93 ± 0.850	75.7
FC	76.3 ± 0.306	43.5
FS	58.9 ± 0.404	52.8