In Situ Observation and Mechanism Study on the Oxidation Process of Magnesium under Trace Oxygen Condition

Abstract

Abstract: The study on the oxidation process of magnesium (Mg) alloy and corresponding control mechanism by in situ real-time observation has been a hotspot in the field of surface treatment for magnesium. In this study, magnesium film was kept for 10 h at 400 ℃ in a furnace, and the faceted Mg nanopores were prepared by focused electron beam technology under a transmission electron microscope (TEM). The slow oxidation and growth dynamics of the surface lattices at the vicinity of Mg nanopores under trace oxygen condition were observed using in situ high-resolution transmission electron microscopy techniques, while the corresponding mechanisms were also researched. The results show that the oxidation proceeds via an adatom process, resulting in the diffusion of Mg atoms from the substrate to the subsurface of oxides, and the oxidation growth process is mainly achieved via layer-by-layer epitaxial growth of MgO. The faceted morphology enclosed by {200} lattice planes attributes to the typical anisotropic growth. The study on the roles of defects in the process of oxidation growth shows that the defects, such as vacancies and dislocatios, promote the oxidation process, whereas the large-angle grain boundary of the twinning inhibits the rotation or migration of the grain boundary, which is conducive to improve the corrosion resistance of magnesium alloy.

Key words: magnesium alloy, trace oxygen condition, oxidation mechanism, in situ observation, magnesium nanopore, adatom process, twinning, anisotropic growth

CLC Number:

TG174.4

LU Jinghan, WU Shujing, LU Zehao, DU Yumeng, MA Yongqiang, CAO Chong. In Situ Observation and Mechanism Study on the Oxidation Process of Magnesium under Trace Oxygen Condition[J]. Journal of Synthetic Crystals, 2023, 52(3): 520-525.

References

[1] 陈锡泼. 镁合金熔炉温控系统的研究与开发[D]. 杭州: 浙江工业大学, 2009.
CHEN X P. Research and development of temperature control system for magnesium alloy melting furnace[D]. Hangzhou: Zhejiang University of Technology, 2009 (in Chinese).
[2] 丁文江. 镁合金科学与技术[M]. 北京: 科学出版社, 2007.
DING W J. The technology of magnesium alloy[M]. Beijing: Science Press, 2007 (in Chinese).
[3] POLLOCK T M. Materials science. Weight loss with magnesium alloys[J]. Science, 2010, 328(5981): 986-987.
[4] 明玥, 游国强, 姚繁锦, 等. 金属镁的氧化及氧化机理研究进展[J]. 材料导报, 2021, 35(19): 19134-19141.
MING Y, YOU G Q, YAO F J, et al. Research progress on oxidation and oxidation mechanism of magnesium[J]. Materials Reports, 2021, 35(19): 19134-19141 (in Chinese).
[5] SCHRÖDER E, FASEL R, KIEJNA A. O adsorption and incipient oxidation of the Mg(0001) surface[J]. Physical Review B, 2004, 69(11): 115431.
[6] 潘娜, 卫英慧, 侯利锋, 等. AZ61镁合金高温氧化过程[J]. 材料热处理学报, 2013, 34(3): 67-72.
PAN N, WEI Y H, HOU L F, et al. Oxidation process of AZ61 magnesium alloy at high temperature[J]. Transactions of Materials and Heat Treatment, 2013, 34(3): 67-72 (in Chinese).
[7] PILLING N B, BEDWORTH R E. The oxidation of metal at high temperature[J]. Journal of Institute of Metals, 1923, 29: 529-591.
[8] CZERWINSKI F. The reactive element effect on high-temperature oxidation of magnesium[J]. International Materials Reviews, 2015, 60(5): 264-296.
[9] GULBRANSEN E A. The oxidation and evaporation of magnesium at temperatures from 400 ℃ to 500 ℃[J]. Transactions of the Electrochemical Society, 1945, 87(1): 589.
[10] AYDIN D S, BAYINDIR Z, PEKGULERYUZ M O. The high temperature oxidation behavior of Mg-Nd alloys. Part II: the effect of the two-phase microstructure on the on-set of oxidation and on oxide morphology[J]. Journal of Alloys and Compounds, 2014, 584: 558-565.
[11] 范烨力, 王伟. 镁合金表面制备Al₂O₃/Ni复合涂层抗腐蚀性的研究[J]. 人工晶体学报, 2017, 46(9): 1809-1813+1817.
FAN Y L, WANG W. Corrosion resistance of Al₂O₃/Ni composite coating prepared on Mg alloy surface[J]. Journal of Synthetic Crystals, 2017, 46(9): 1809-1813+1817 (in Chinese).
[12] CZERWINSKI F. The oxidation behaviour of an AZ91D magnesium alloy at high temperatures[J]. Acta Materialia, 2002, 50(10): 2639-2654.
[13] CZERWINSKI F. Oxidation characteristics of magnesium alloys[J]. JOM, 2012, 64(12): 1477-1483.
[14] SCHRÖDER E, FASEL R, KIEJNA A. Mg(0001) surface oxidation: a two-dimensional oxide phase[J]. Physical Review B, 2004, 69(19): 193405.
[15] FRANCIS M F, TAYLOR C D. First-principles insights into the structure of the incipient magnesium oxide and its instability to decomposition: oxygen chemisorption to Mg(0001) and thermodynamic stability[J]. Physical Review B, 2013, 87(7): 075450.
[16] SUN Y, WANG J M, GUO J X, et al. Atomic-scale oxidation mechanisms of single-crystal magnesium[J]. Nanoscale, 2019, 11(48): 23346-23356.
[17] ZHENG H, WU S J, SHENG H P, et al. Direct atomic-scale observation of layer-by-layer oxide growth during magnesium oxidation[J]. Applied Physics Letters, 2014, 104(14): 141906.
[18] ZHOU G W, LUO L L, LI L, et al. Step-edge-induced oxide growth during the oxidation of Cu surfaces[J]. Physical Review Letters, 2012, 109(23): 235502.
[19] KANTOROVICH L N, GILLAN M J. Adsorption of atomic and molecular oxygen on the MgO (001) surface[J]. Surface Science, 1997, 374(1/2/3): 373-386.
[20] EGERTON R F, LI P, MALAC M. Radiation damage in the TEM and SEM[J]. Micron, 2004, 35(6): 399-409.
[21] KOOI B J, PALASANTZAS G, DE HOSSON J T M. Gas-phase synthesis of magnesium nanoparticles: a high-resolution transmission electron microscopy study[J]. Applied Physics Letters, 2006, 89(16): 161914.
[22] BIERMAN M J, LAU Y K, KVIT A V, et al. Dislocation-driven nanowire growth and Eshelby twist[J]. Science, 2008, 320(5879): 1060-1063.
[23] CAO F, ZHENG H, JIA S F, et al. Atomistic observation of phase transitions in calcium sulfates under electron irradiation[J]. The Journal of Physical Chemistry C, 2015, 119(38): 22244-22248.