## 3 Results and Discussion
### Characterization
There were characteristic peaks such as P-O, C-O, and O-H functional groups on specimens treated by LAB (Figure 5B,C). Among these, several bands between 900 and 1200 cm\({}^{-1}\) represent the stretching  
Figure 4: The surface wettability titanium sheet has different surface treatments. (**A**) Image of surface contact angle. (**B**) Quantitative analysis of the contact angle was performed. Means with different letters were significantly different (\(p<0.05\), mean \(\pm\) SD, \(n=3\)). mode of P-O bonds. The PO4\({}^{3-}\)v1 bond is at 962 cm\({}^{-1}\), and the PO4\({}^{3-}\)v3 bond is at 1038 cm\({}^{-1}\). However, there was a bifurcation at half height of 962 cm\({}^{-1}\). This is not a typical HA functional group. This shape indicated the presence of hydroxylapatite with lower crystallinity [38]. Obvious absorption peaks were found at 1419-1486 cm\({}^{-1}\) to be the C-O bonding group, and the v3 bonding of CO\({}_{3}\) is located at 1400-1580 and 870 cm\({}^{-1}\). The presence of the two peaks indicated that the phosphate position in the HA structure was replaced by carbonate [39]. Therefore, crystals formed on the surface were carbonated HAp (CHA, Ca\({}_{10}\)(PO\({}_{4}\))\({}_{6}\)(CO\({}_{3}\))). This reaction was caused by the participation of carbon dioxide dissolved in the air and water. At 1595-1630 cm\({}^{-1}\), the characteristic peak produced by the vibration of H\({}_{2}\)O molecules was the bonding functional group of symmetrical H-O-H. The asymmetrical O-H bonding functional group appeared in the range of 3800-3200 cm\({}^{-1}\). This characteristic peak represents water molecules adsorbed onto the surface [40]. Figure 5: The characteristics of the titanium sheet with different surface treatments and samples after LAB treatments. (**A–C**) FTIR spectra obtained from original, LAB CaP solution and LAB CoHA solution. (**D–F**) XRD patterns of the original, LAB CaP solution, and LAB CoHA solution. The XRD analysis of the sample before LAB treatment indicated the crystal phase structure of titanium (Figure 5D). Compared to the literature, the crystalline phase structure of the titanium plate after LAB treatment (Figure 5E,F) showed the diffraction front of HA [41]. The CaP deposited on the surface of the titanium sheet treated with the CaP solution and LAB was mainly HA. A similar HA structure was also observed on the titanium sheet after immersion in the CoHA solution and LAB. However, it may be that the Co content was too small, so the diffraction peak of cobalt oxide was not observed (Figure 5F). In addition, it was found that diffraction of the deposited HA was more pronounced in the CaP solution compared to LAB treatment of the CoHA solution. It may be that the CaP solution was a supersaturated CaP solution suitable for the hydrothermal method with a pH of 7.4, and the CoHA solution was an electrolyte with a pH of 3.52, which is an acidic solution. The principle of the LAB method used in this experiment is to use thermally induced HA deposition similar to the hydrothermal method. Therefore, the CaP solution had an obvious crystallization performance. In addition, samples were transformed into super-hydrophilic surfaces after LAB treatment (Figure 4B). This helped improve the biocompatibility of the material surface and cell adhesion. Based on the above SEM observations, test pieces with different surface treatments were treated with the CaP solution and the CoHA solution and LAB. The results showed that in addition to pure titanium, no crystallization was observed after LAB treatment, but other groups had found the presence of CaP and CoHA crystals. The EDX analysis of the surface elemental composition had calcium and phosphorus in the CaP solution treated with LAB. In the CoHA solution treated with LAB, calcium, phosphorus, and cobalt were present, except in the untreated group. The results of ATR-FTIR confirmed that CaP and CoHA synthesized in this study were indeed composed of HA groups.