Improved corrosion resistance of hydroxyapatite coating on carbon fiber by applying SiC interlayer

A hydroxyapatite (HA, Ca₁₀(PO₄)₆(OH)₂) coating is successfully fabricated on carbon fiber (CF) with SiC interlayer prepared via pack cementation method at 1773 K, 1873 K, 2073 K and 2273 K. The morphologies and microstructures of the SiC interlayer and HA coating are analyzed. The corrosion performance is evaluated by electrochemical behavior in simulated body fluid (SBF). The results show that the morphologies and crystalline structures of SiC interlayers vary with temperatures. The SiC interlayer improves the surface wettability for CF. The HA coating deposited on SiC interlayer modified CF exhibits denser and more uniform structure than that on the CF. Corrosion test shows that the corrosion potential (E_corr) and corrosion current density (I_corr) for HA coated CF with SiC interlayer are −0.13 V and 0.64 × 10⁻⁵ A/cm², respectively. For HA coated CF, the E_corr and I_corr are −0.15 V and 1.25 × 10⁻⁵ A/cm², respectively. The E_corr increases and the I_corr decreases resulting from the introduction of SiC interlayer. The corrosion resistance of HA coated CF with SiC interlayer in SBF is better than that of HA coated CF. The HA coated CF with SiC interlayer would be possible for biological application.