Growth behaviour of cerium-based conversion coating on HF pre-treated Zn-5%Al alloy

摘要

The effects of HF pre-treatment on the cerium-based conversion coating on a Zn-5% Al alloy were investigated using a combination of scanning electron microscopy, energy-dispersive X-ray spectroscopy, X-ray photoelectron spectroscopy, and electrochemical impedance spectroscopy. The results revealed that a porous structure appeared in the Al-rich phase of Zn-5% Al alloy after HF pre-treatment, and the cerium conversion coating with pre-treatment was preferentially deposited on the surface of Al-rich phase and grew fast. Moreover, the corrosion resistance of the cerium conversion coating was improved by HF pre-treatment.

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