题目：

High resolution characterization of Hexagonal Boron Nitride Coatings exposed to aqueous and air oxidative environments

作者：

Lanlan Jiang^1,a, Na Xiao^1,a, Bingru Wang^1,a, Enric Grustan-Gutierrez¹, Xu Jing¹, Petr Babor², Miroslav Kolíbal², Guangyuan Lu³, Tianru Wu³, Haomin Wang², Fei Hui¹, Yuanyuan Shi¹, Bo Song¹, Xiaoming Xie^3,4, Mario Lanza^1,*

单位：

¹Institute of Functional Nano & Soft Materials (FUNSOM), Soochow University, 199 Ren-AiRoad, Suzhou 215123, China.

²CEITEC BUT，Brno University of Technology，Brno，Czech Republic.

³State Key Laboratory of Functional Materials for Informatics, Shanghai Institute of Microsystems and Information Technology, Chinese Academy of Sciences，Shanghai, China.

⁴School of Physical Science and Technology，Shanghai Tech University，Shanghai, China.

^aThese authors contributed to this work equally.

摘要：

Hexagonal boron nitride (h-BN) is believed to offer better passivation to metallic surfaces than graphene owing to its insulating nature, which facilitates blocking the flow of electrons, thereby preventing the occurrence of galvanic reactions. Nevertheless, this may not be the case when an h-BN-protected material is exposed to aqueous environments. In this work, we analyzed the stability of mono and multilayer h-BN stacks exposed to H₂O₂ and atmospheric conditions. Our experiments revealed that monolayer h-BN is as inefficient as graphene as a protective coating when exposed to H₂O₂. Multilayer h-BN offered a good degree of protection. Monolayer h-BN was found to be ineffective in an air atmosphere as well. Even a 10�15 layers-thick h-BN stack could not completely protect the surface of the metal under consideration. By combining Auger electron spectroscopy and secondary ion mass spectrometry techniques, we observed that oxygen could diffuse through the grain boundaries of the h-BN stack to reach the metallic substrate. Fortunately, because of the diffusive nature of the process, the oxidized area did not increase with time once a saturated state was reached. This makes multilayer (not monolayer) h-BN a suitable long-term oxidation barrier. Oxygen infiltration could not be observed by X-ray photoelectron spectroscopy. This technique cannot assess the chemical composition of the deeper layers of a material. Hence, the previous reports, which relied on XPS to analyze the passivating properties of h-BN and graphene, may have ignored some important subsurface phenomena. The results obtained in this study provide new insights into the passivating properties of mono and multilayer h-BN in aqueous media and the degradation kinetics of h-BN-coated metals exposed to an air environment.

影响因子：

8.893

分区情况：

一区

链接：

http://link.springer.com/article/10.1007/s12274-016-1393-2

责任编辑：向丹婷 联系方式：dtxiang@suda.edu.cn