Effect of cerium ion (III) on corrosion resistance of organic–inorganic hybrid coating on surface of aluminum-tube used in refrigeration equipment

Organic–inorganic hybrid coating on the surface of aluminum-tube used in refrigeration equipment using cerium ion (III) as the additive was fabricated by sol–gel method, and the structure of the coating was confirmed by FT-IR. The results of the characterization show that the corrosion resistance of the coating with 1.5 mmol/L cerium ion (III) gains significant improvement, in which the colour retention time of CuSO4 extends to 500 s, the anti-acid and alkali corrosion rates reduce by 67% and 70% compared with the blank one, respectively, and the salt spray tests also show good corrosion resistance. The electrochemical tests demonstrate that the self-corrosion current density and potential of the sample with hybrid coating are about 2.877×10−7 A/cm2 and –0.550 V, respectively. The metallographic and SEM images show that the hybrid coating is uniform and dense, and the EDS analysis confirms that the coating is mainly composed of Al, Si and Ce elements.