Effect of substrate temperature on mechanical and electrochemical properties of flame-sprayed coatings for Titanium...

BackgroundHydroxyapatite (HA) coatings on titanium (Ti) implants are widely studied owing to their biocompatibility and osteoconductivity. However, the effect of substrate temperature during flame spraying on coating performance remains unclear.ObjectiveThis study investigated the influence of substrate temperature on the microstructure, mechanical properties, and electrochemical behavior of flame-sprayed HA coatings on Ti implants.MethodsHA coatings were deposited on commercially pure Ti Grade 2 substrates by flame spraying at room temperature (RT) and 300 °C. The coatings were characterized by XRD, FTIR, XPS, SEM, and EDS. Surface roughness, adhesion strength, abrasion resistance, potentiodynamic polarization, and electrochemical impedance spectroscopy were evaluated.ResultsSubstrate heating at 300 °C modified the crystalline phase composition and slightly increased the apparent HA crystallite size and crystalline peak index. The 300 °C coating exhibited a more compact surface morphology, higher adhesion strength, lower abrasion-induced mass loss, lower corrosion current density, and higher charge transfer resistance than the RT coating.ConclusionSubstrate heating at 300 °C improved the mechanical durability and corrosion resistance of flame-sprayed HA coatings, indicating its usefulness for enhancing Ti implant coating performance.