Investigations of FA+TiO2 coating on Ti-6Al-4V substrates using Nd-YAG laser

• Main Authors: Yu-Sheng Ko, 柯佑昇
• Other Authors: Tsung-Yuan Kuo
• Format: Others
• Language: zh-TW
• Published: 100
• Online Access: http://ndltd.ncl.edu.tw/handle/11226562852729681615

碩士 === 南台科技大學 === 機械工程系 === 99 === To improve the bioactivity of Ti6Al4V alloy implant and enhance mechanical properties of fluorapatite(FA). This study used Fluorapatite (FA), whose anti-dissolution rate is better than that of HA, as coating material and added two kinds of TiO2 powder (containing Anatase phase (A) or Rutile phase (R)) which not only can improve the osteoblast adhesion and induce the growth of bone cells but also can enhance the bonding strength between the coatings and the substrate. Then, these two kinds of FA+TiO2 and different ratio of TiO2 powder coating materials were deposited on Ti-6Al-4V substrates by using Nd-YAG laser cladding process. Results show that, FA+R and FA+A coating material of cladding layer and transition layer has a serious crack at the lowest speed (200mm/min), but with cladding travel speed faster the crack decrease. Higher magnification SEM image shows that the coating layer of FA+R specimens is mainly cellular-like structure while the transition layer is coral-like structure. For the FA+A specimens, the coating layer and the transition layer have the similar microstructure, mostly cellular-like or cellular dendrite-like structure. After the specimens were soaked in SBF for 2, 7, and 14 days, dense ball-like apatite grew on the surface of the FA+R coating layer faster than on the surface of the FA+A specimens. The corresponding Ca/P value of FA+R specimens also dropped faster. After FA+R specimens were soaked in SBF for 2 days and FA+A for 7 days, their Ca/P values approached the best bioactivity value. In addition, after changing the ratio of FA and TiO2, Results show that, TiO2 content increases, the weld penetration depth decreased, the cladding microstructure changed from a fine cellular-like structure to cellular dendrite-like structure, between dendrite and dendritic gap will help the growth of cell adhesion. After the specimens were soaked in SBF for 2, 7, and 14 days, FA+0.8A and FA+0.5A of the surface faster than the FA+A formation of dense spherical apatite. The corresponding Ca/P value also dropped faster. Three specimens after immersed in SBF after 7 days, the coating material of the Ca/P value can be close to the biological activity of the best value. With the increase of soaking time, apatite was gradually covered coated layer surface.