TC4 micro-arc oxidation (MAO) coatings were prepared by adding SiO2 nanoparticles or sodium silicate to the sodium meta-aluminate-based electrolyte. The effect of additives was investigated by XRD, SEM, EDS, electrochemical and wear tests. The results show that additives can considerably accelerate the formation of MAO coatings. The coatings are mostly composed of rutile and anatase TiO2, α-Al2O3, γ-Al2O3, Al2TiO5 and SiO2. Sodium silicate and SiO2 nanoparticles added to the coating can effectively reduce the size of micropores and increase its thickness, whereas SiO2 nanoparticles with superior physical properties can be directly deposited at the discharge channel, significantly increasing the coating's resistance to wear and corrosion. The coating with SiO2 nanoparticles exhibits the best overall performance, with the lowest corrosion rate and average friction coefficient of 4.095×10-5 mm/a and 0.30, respectively.