Hydroxyapatite coating on titanium substrate with titania buffer layer processed by sol-gel method

Hae Won Kim, Young Hag Koh, Long Hao Li, Sook Lee, Hyoun Ee Kim

Research output: Contribution to journalArticlepeer-review

365 Citations (Scopus)


Hydroxyapatite (HA) was coated onto a titanium (Ti) substrate with the insertion of a titania (TiO2) buffer layer by the sol-gel method. The HA layer was employed to enhance the bioactivity and osteoconductivity of the Ti substrate, and the TiO2 buffer layer was inserted to improve the bonding strength between the HA layer and Ti substrate, as well as to prevent the corrosion of the Ti substrate. The HA layer coated over the TiO 2 showed a typical apatite phase at 400°C and the phase intensity increased above 450°C. The sol-gel derived HA and TiO2 films, with thicknesses of approximately 800 and 200nm, respectively, adhered tightly to each other and to the Ti substrate. The bonding strength of the HA/TiO2 double layer coating on Ti was markedly improved when compared to that of the HA single coating on Ti. The highest strength of the double layer coating was 55MPa after heat treatment at 500°C. The improvement in bonding strength with the insertion of TiO2 was attributed to the resulting enhanced chemical affinity of TiO2 toward the HA layer, as well as toward the Ti substrate. Human osteoblast-like cells, cultured on the HA/TiO2 coating surface, proliferated in a similar manner to those on the TiO2 single coating and on the pure Ti surfaces. However, the alkaline phosphatase activity of the cells on the HA/TiO2 double layer was expressed to a higher degree than that on the TiO2 single coating and pure Ti surfaces. The corrosion resistance of Ti was improved by the presence of the TiO2 coating, as confirmed by a potentiodynamic polarization test.

Original languageEnglish
Pages (from-to)2533-2538
Number of pages6
Issue number13
Publication statusPublished - 2004 Jun
Externally publishedYes


  • Bonding strength
  • Cell response
  • Corrosion resistance
  • Hydroxyapatite coating
  • Sol-gel method
  • Titania buffer layer
  • Titanium substrate

ASJC Scopus subject areas

  • Bioengineering
  • Ceramics and Composites
  • Biophysics
  • Biomaterials
  • Mechanics of Materials


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