Effect of Ti₃SiC₂ Particle Mass Concentration on Microstructure and Corrosion Resistance of Micro-arc Oxide Layer on 6063 Alloy

Electrolyte solutions composed of 10 g · L⁻¹ Na2Sio3,2 g · L⁻¹ NaOH and x g · L⁻¹ Ti₃AlC₂ nanopartides (x=1,2,4,8) were prepered. In the solution micro-arc oxidation was performed on 6063 alloy. The effects of the mass concentration of Ti₃SiC₂ in the electrolyte solution on the morphology, surface roughness, micro-composition, phase composition and corrosion resistance of the micro-arc oxide layer were studied. The results show that with the increase of the mass concentration of Ti₃SiC₂, the number of pores in the micro-arc oxide layer increased, the micro-cracks expanded gradually, and the density decreased. The phases of micro-arc oxide layers under different concentration of Ti₃SiC₂ mainly consisted of aluminum, α-Al₂O₃, γ-Al₂O₃ and a small amount of Ti₃SiC₂. When the mass concentration of Ti₃SiC₂ was 4 g · L⁻¹, the surface roughness of the micro-arc oxide layer was the smallest, the self-corrosion potential was the largest, the self-corrosion current density was the smallest, the arc resistance radius was the largest, the phase angle was the highest and closest to 90° at the medium frequency, and the inpedance modulus as the frequency approached 0 was the largest; the corrosion resistance of the micro-arc oxide layer prepared under this condition was the best.