Bioconductivity of plasma sprayed dicalcium silicate/titanium composite coatings on Ti–6Al–4V alloy

Dicalcium silicate (C2S) based composite coatings reinforced with titanium were fabricated via atmospheric plasma spraying on Ti–6Al–4V alloy substrates. The bonding strength of the coatings with different Ti contents was investigated. The phases and morphologies of the coatings were identified by X-ray diffraction and scanning electron microscopy. The cross-sectional pictures of the coatings showed that the composite coatings have a typical lamellar structure with alternating C2S and Ti phases. The addition of Ti can effectively inhibit the propagation of the cracks in the coatings and increase the durability of the coatings in simulated body fluid (SBF). The bonding strengths of the composite coatings increase with increase in Ti content, varying from 36.6 MPa for CT3 coating to 46.2 MPa for CT5 coating and 49.0 MPa for CT7 coating. The composite coatings were immersed in SBF solution for bioconductivity appraisal. The surfaces of the CT3 and CT5 coatings were covered by hydroxylapatite (HAp) within 7 days immersion in SBF solution, while no HAp appeared on the CT7 coating surface even after immersion in SBF solution for 14 days.