Thin sol-gel-derived silica-coatings on CP-titania and bioactivity thereupon.

Silica-coatings prepared by sol-gel method was coated on CP-titania cones and discs. Thin coatings of less than approximately 0.3 micron were produced. The greatest advantage with the Si-gel coatings is that the densification of the gel takes place at already 500 degrees C, thus not changing the character of the metal surface. The coatings showed to passivate the surface of the CP-titania specimen, provided that the thickness did not exceed 0.3 micron. That seemed to be the critical thickness for a smooth and intact coating. Thicker coatings of Si-gel scales easily off.