Surface Characteristics of Anodized and Hydrothermally-Treated Ti-6Al-7Nb Alloy

양극산화와 열수처리한 Ti-6Al-7Nb 합금의 표면 특성

  • Kim, Moon-Young (Department of Prosthodontics, School of Dentistry and Institute of Oral Biosciences, Chonbuk National University) ;
  • Song, Kwang-Yeob (Department of Prosthodontics, School of Dentistry and Institute of Oral Biosciences, Chonbuk National University) ;
  • Bae, Tae-Sung (Department of Dental Materials, School of Dentistry and Institute of Oral Biosciences, Chonbuk National University)
  • 김문영 (전북대학교 치과대학 치과보철학교실 및 구강생체과학연구소) ;
  • 송광엽 (전북대학교 치과대학 치과보철학교실 및 구강생체과학연구소) ;
  • 배태성 (전북대학교 치과대학 치과재료학교실 및 구강생체과학연구소)
  • Published : 2005.06.30


This study was performed to investigate the surface properties and in vitro biocompatibility of electrochemically oxidized Ti-6Al-7Nb alloy by anodic spark discharge technique. Discs of Ti-6Al-7Nb alloy of 20 mm in diameter and 2 mm in thickness were polished sequentially from #300 to 1000 SiC paper, ultrasonically washed with acetone and distilled water for 5 min, and dried in an oven at $50^{\circ}C$ for 24 hours. Anodizing was performed using a regulated DC power supply. The applied voltages were given at 240, 280, 320, and 360 V and current density of $30mA/cm^2$. Hydrothermal treatment was conducted by high pressure steam at $300^{\circ}C$ for 2 hours using a autoclave. Samples were soaked in the Hanks' solution with pH 7.4 at $36.5^{\circ}C$ during 30 days. The results obtained were summarized as follows; 1. The oxide films were porous with pore size of $1{\sim}5{\mu}m$. The size of micropores increased with increasing the spark forming voltage. 2. The main crystal structure of the anodic oxide film was anatase type as analyzed with thin-film X-ray diffractometery. 3. Needle-like hydroxyapatite (HA) crystals were observed on anodic oxide films after hydrothermal treatment at $300^{\circ}C$ for 2 hours. The precipitation of HA crystals was accelerated with increasing the spark forming voltage. 4. The precipitation of the fine asperity-like HA crystals were observed after being immersed in Hanks' solution at $37^{\circ}C$. The precipitation of HA crystals was accelerated with increasing the spark forming voltage and the time of immersion in Hanks' solution. 5. The Ca/P ratio of the precipitated HA layer was equivalent to that of HA crystal as increasing the spark forming voltage and the time of immersion in Hanks' solution.



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