A black conversion coating produced by hot corrosion of magnesium with deep eutectic solvent membrane
2018; Elsevier BV; Volume: 357; Linguagem: Inglês
10.1016/j.surfcoat.2018.10.062
ISSN1879-3347
AutoresLiting Guo, Changdong Gu, Jialei Zhang, Xiaoqing Wang, Kangyan Wang, Yuan Jin, Jiangping Tu,
Tópico(s)Layered Double Hydroxides Synthesis and Applications
ResumoFormation of conversion coatings involves chemical reactions at the solid/liquid interface. A liquid membrane on Mg and its alloys was adopted to fabricate conversion films based on the hot corrosion reactions at the choline chloride-urea deep eutectic solvent (DES) membrane/substrate interface. Colour and corrosion resistance of the conversion films on pure Mg and AZ31B Mg alloys are found to be highly depended on the hot corrosion time. The conversion film possesses a porous surface. The size of crater-like features on the AZ31B is much smaller than that on the pure Mg (~80 nm vs. ~0.7 μm). The conversion film is mainly composed of MgCO3 and MgH2. The AZ31B magnesium alloy after the hot corrosion treatment by DES membrane shows black appearance, and the reflectance is very low (~10%) from visible light to near infrared light (400–2000 nm). Electrochemical polarization measurement and immersion test in NaCl aqueous solution show that the conversion film can improve the corrosion resistance of the substrates obviously.
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