A hydroxyapatite/fluorapatite (HA/FA) double layer was coated on ZrO 2 by a powder slurry method. The FA layer between the HA layer and the ZrO 2 substrate was effective in suppressing the reaction between HA and ZrO 2. The rheological properties of the slurry and the thermal treatment conditions were optimized. Addition of small amounts of tri-ethyl phosphate dispersant and polyvinylbutyral binder (up to 5 wt%) was effective in reducing the slurry viscosity, even at high loadings of HA powder. Each layer (HA, FA) was deposited on ZrO 2 repeatedly to induce a uniform layer, and the final heat treatment was carried out above 1200°C to consolidate the coating layer. During this process, without the FA-intermediate layer, a severe reaction between HA and ZrO 2 occurred to form tri-calcium phosphate and CaZrO 3 products. However, the presence of the FA layer between HA and ZrO 2 effectively suppressed the reaction up to 1300°C. The obtained HA/FA double coating layer was micro-porous and relatively rough, but was firmly adhered to the ZrO 2 substrate, having a bonding strength of approximately 25 MPa after heat treatment above 1200°C. The osteoblast-like cells cultured on the HA/FA coating layer spread and proliferated favorably, having a cell proliferation rate comparable to that of a plastic control and HA bulk ceramic.
|Number of pages||7|
|Journal||Journal of the American Ceramic Society|
|Publication status||Published - 2006 Aug|
ASJC Scopus subject areas
- Ceramics and Composites
- Materials Chemistry