The effect of bond coat on mechanical properties of plasma sprayed bioglass-titanium coatings

Bioglass, known as 45S5 (45% SiO₂, 6% P₂O ₅, 24.5% CaO and 24.5% Na₂O all in weight percent), was plasma sprayed onto a titanium substrate with and without Amdry 6250 (60% Al₂O₃ 40% TiO₂) as bond coating layer. Mechanical properties were evaluated in accordance with the ASTM C633 method and scanning electron microscopy was used for the microstructural characterization. Results indicated that it is possible to coat bioglass on titanium substrate by utilizing similar conditions used for hydroxyapatite. Application of bond coat layer in the plasma spraying of (45S5) bioglass on titanium substrate has increased the bonding strength about three times. The adhesive bonding observed at the bioglass metal interface turned into cohesive bonding by application of the bond coating layer. It has been observed that there is a uniform coating layer with a thickness of 110 and 80 μm depending on coating type with a little amount of porosity.