High-resolution characterization of hexagonal boron nitride coatings exposed to aqueous and air oxidative environments

Jiang, L. et al. (2017) High-resolution characterization of hexagonal boron nitride coatings exposed to aqueous and air oxidative environments. Nano Research, 10(6), pp. 2046-2055. (doi: 10.1007/s12274-016-1393-2)

Abstract

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.

• Item Type: Articles
• Additional Information: This work has been supported by the Young 1000 Global Talent Recruitment Program of the Ministry of Education of China, the National Natural Science Foundation of China (Nos. 61502326, 41550110223, and 11661131002), the Jiangsu Government (No. BK20150343), the Ministry of Finance of China (No. SX21400213) and the National Basic Research Program of China (No. 2015CB932700). The Collaborative Innovation Center of Suzhou Nano Science & Technology, the Jiangsu Key Laboratory for Carbon-Based Functional Materials & Devices and the Priority Academic Program Development of Jiangsu Higher Education Institutions are also acknowledged. Part of this work was carried out with the excellent support of the Nanofabrication and Nanocharacterization Core Facility of CEITEC under CEITEC Nano project (No. LM2015041). P. B. and M. K. acknowledge support of Ministry of Education, Youth and Sports of the Czech Republic under the project CEITEC 2020 (No. LQ1601).
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Grustan Gutierrez, Dr Enric
• Authors: Jiang, L., Xiao, N., Wang, B., Grustan Gutierrez, E., Jing, X., Babor, P., Kolíbal, M., Lu, G., Wu, T., Wang, H., Hui, F., Shi, Y., Song, B., Xie, X., and Lanza, M.
• College/School: College of Science and Engineering > School of Engineering > Autonomous Systems and Connectivity
• Journal Name: Nano Research
• Publisher: Springer Verlag
• ISSN: 1998-0124
• ISSN (Online): 1998-0000
• Published Online: 26 January 2017