Bioactive coating on titanium using calcium-containing methylsiloxane

A bioactive coating of Ca-containing methylsiloxane on a titanium surface was investigated. The coatings have double-layered structure consisted of underlying methylsiloxane (MS) and with an incorporated Ca content methylsiloxane (MS-Ca) top layer. The top layer of MS-Ca was prepared from methyltriethoxysilane containing 2.5 mol% pentaethoxyniobium and 2.5 mol% pentaethoxytantalum followed by the addition of calcium nitrate tetrahydrate with the Ca/Si molar ratio of 0.05 to 0.5 to enhance the formation of bone-like apatite (BLA) in a simulated body fluid (SBF). The adhesive strength of the coating with a 0.05 Ca/Si ratio was 3.5 MPa, while the adhesive strength of the coating tended to decrease to 2 MPa with the increasing Ca content. The adhesive strength of the coating was related to the porosity, which depended on the Ca content.