The Incorporation of Nano-MoSi2 Particles into a Black PEO Coating on Ti Alloy and Its Corrosion Performance

Tinted plasma electrolytic oxidized (PEO) coatings have been widely applied on the surface of Ti alloys in aerospace field. In this study, a black PEO coating was successfully developed on TC4 alloy, incorporating MoSi2 nanoparticles in situ within the coating matrix to enhance its corrosion resistance. The results indicated that the incorporation of MoSi2 nanoparticles noticeably influence the coating morphology. The pore size decreased while coating thickness decreased from 15 μm to 12 μm. The incorporation of MoSi2 enhanced the barrier property of the inner PEO layer, as well as decreased the surface roughness and increased the coating hardness, which improved the corrosion resistance. The icorr dropped to 1.49 ± 0.58 × 10−7 A/cm2 after the incorporation of the nanoparticles. A black PEO coating with particle addition was suggested for broader application on Ti alloys.