Brome-like rare-earth film for durable protection of magnesium alloy

Background Due to the highly-active chemical and electrochemical properties, magnesium alloys are easily damaged in harsh environments. So surface films that can provide durable protection are highly desired in applications of magnesium alloys. Methods The film was prepared by the hydrothermal treatment in lanthanum-nitrate solution and the chemical modification in stearic-acid solution. The film was characterized by FESEM, AFM, XPS, FTIR, Raman, CA, high-speed camera, electrochemical polarization and impedance methods. Various mechanical, physical and chemical durability tests were used to comprehensively evaluate the film durability. Findings The as-prepared film has brome-like morphology and is composed of (hydr)oxides/stearates of Mg and La. The film-coated magnesium alloy surface has a static WCA of 154.7 ° and a SA of 6.0 °, showing superhydrophobicity and low-adhesion. The as-prepared film demonstrates durable self-cleaning function and high corrosion resistance of 150 kΩ cm 2 . More importantly, various durability tests confirm that the as-prepared film can provide durable protection for magnesium alloys, which is expected to play an important role in harsh-environment applications of magnesium alloys.