Study of Hydroxyapatite/Bioactive Glass Composites Plasma Sprayed on Ti6Al4V

• Main Authors: May-Lan Liu, 劉美蘭
• Other Authors: Jiin-Huey Chern Lin
• Format: Others
• Language: zh-TW
• Published: 1993
• Online Access: http://ndltd.ncl.edu.tw/handle/59157647712720341576

碩士 === 國立成功大學 === 材料科學(工程)研究所 === 81 === HA-coated Ti6Al4V has recently been used as a bone subs- titute in orthopedic and dental application, because of its favorable bioactivity and mechanical properties. Plasma spray- ing technique appears to be the most favorable one in term of mechanical properties, biocorrosion resistance, coating-subs- trate bonding strength, and process feasibility. Studies in the literature have shown that the bioactivity of calcium phosphate bioactive glass (BG) is higher than that of HA. In an attempt to increase the bioactivity of HA-coated Ti6Al4V and enhance the bonding strength between coating and substrate, in the present study, HA/BG composite (including 75 HA/25BG, 50HA/50BG and 25HA/75BG in weight) are applied onto Ti6Al4V using a plasma spraying technique. Microstructure and phase changes of the composite coatings after plasma spraying are studied. The coating-substrate bond- ing strength is evaluated using an Instron following ASTM C633 method. Since accidentally observing a degradationin the mea- sured bonding strength of plasma-sprayed HA on Ti6Al4V when the coated specimens were exposed in humid air for a few days, we have carried out a systematic study of environmental effect (particularly humidity and storage time) on bonding strength. In vitro behavior of these coatings were also studied by im- mersion in Hank''s physiological solution. The results indicate that surface roughness of HA/BG com- posite coatings are much larger than HA coating. The HA/BG composite coating offers sufficient bonding strength and are less affected by air humidity. When immersed in Hank''s solu- tion, HA/BG coatings are more active than pure HA or BG coat- ing. After immersed about 10 days, a Ca, P-rich apatite layer forms on all coatings (BG, HA, or HA/BG). All of them, 75HA/25 BG coating performs the best. Since, implants bonded with bone directly is by means of the apatite structure. We except that HA/BG composite coating will behave well in vivo.