Mg alloys suffer from inadequate corrosion resistance, which significantly hampers their widespread application as lightweight structural materials. Recently, scientists from the Center for Advancing Materials Performance from the Nanoscale (CAMP-Nano), Xi’an Jiaotong University, demonstrated an environmentally benign method to grow a protective film on the surface of Mg/Mg alloy samples at room temperature, via a reaction of excited CO2 with native or corroded Mg alloy surface. The CO2 is activated by using high-energy electron beam irradiation, inside an environmental transmission electron microscope.

This work has been published on the latest Nature Communications, volume 9, 4058 (2018). https://www.nature.com/articles/s41467-018-06433-5. This project is led by Prof. Zhi-Wei Shan. Dr. Yue-Cun Wang is the first author of this paper.

Schematic diagram showing how to transform the native surface to MgCO3.

Compared with untreated samples, the protective layer can elevate the yield stress, suppress plastic instability and prolong compressive strains without peeling off from the metal surface. This environmentally friendly surface treatment method is promising to protect Mg alloys, including those already-corroded on the surface. This work is a success story in making use of the state-of-art in situ environmental TEM to explore a pressing practical problem, from ideas to solution.

The work is supported by the National Key Research and Development Program of China (No. 2017YFB0702001), Natrual Science Foundation of China (51621063, 51601141, 51401239), and Science and Technology Department of Shaanxi Province (2016KTZDGY-04-03 and 2016KTZDGY-04-04), etc.