{"title":"In Situ Investigation Of The Valence States Of Iron-Bearing Phases In Chang’E-5 Lunar Soil Using FIB, AES, And TEM-EELS Techniques","authors":"Yang Li","doi":"10.46770/as.2022.002","DOIUrl":null,"url":null,"abstract":": Nanophase iron (np-Fe 0 ) is a major product of space weathering and its presence significantly alters the reflectance spectral characteristics of lunar soil. Previous studies have established that the np-Fe 0 particles originate from the reduction of ferrous ions in the plasma, in-situ decomposition of olivine and pyroxene, and disproportionation of ferrous ions in solid ferrosilicates. In this study, sample charging effects were eliminated and in situ nanoscale valence state analysis of iron-bearing phases in Chang’E-5 lunar soil was conducted by combining focused ion beam (FIB) microscopy, Auger electron spectroscopy (AES), and transmission electron microscopy-electron energy loss spectroscopy (TEM-EELS) techniques. The results indicate that the contents and valence states of iron in the np-Fe 0 particles, amorphous matrix, and ferrosilicates differ. The np-Fe 0 particles were found to be composed of pure metallic iron, whereas ferrous and ferric iron ions were present in olivine crystals and the amorphous matrix, respectively. The discovery of both metallic and ferric iron in the amorphous matrix of Chang’E-5 lunar soil offers new insights regarding the disproportionation reaction of Fe 2+ on the lunar surface. This study demonstrates that the combination of FIB, AES, and TEM-EELS is an effective and precise approach for analyzing the valence states of iron-bearing phases in lunar soil, which can be extended to other extraterrestrial samples and other multivalent elements.","PeriodicalId":8642,"journal":{"name":"Atomic Spectroscopy","volume":null,"pages":null},"PeriodicalIF":3.4000,"publicationDate":"2022-01-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":"8","resultStr":null,"platform":"Semanticscholar","paperid":null,"PeriodicalName":"Atomic Spectroscopy","FirstCategoryId":"92","ListUrlMain":"https://doi.org/10.46770/as.2022.002","RegionNum":2,"RegionCategory":"化学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":null,"EPubDate":"","PubModel":"","JCR":"Q1","JCRName":"SPECTROSCOPY","Score":null,"Total":0}
引用次数: 8
Abstract
: Nanophase iron (np-Fe 0 ) is a major product of space weathering and its presence significantly alters the reflectance spectral characteristics of lunar soil. Previous studies have established that the np-Fe 0 particles originate from the reduction of ferrous ions in the plasma, in-situ decomposition of olivine and pyroxene, and disproportionation of ferrous ions in solid ferrosilicates. In this study, sample charging effects were eliminated and in situ nanoscale valence state analysis of iron-bearing phases in Chang’E-5 lunar soil was conducted by combining focused ion beam (FIB) microscopy, Auger electron spectroscopy (AES), and transmission electron microscopy-electron energy loss spectroscopy (TEM-EELS) techniques. The results indicate that the contents and valence states of iron in the np-Fe 0 particles, amorphous matrix, and ferrosilicates differ. The np-Fe 0 particles were found to be composed of pure metallic iron, whereas ferrous and ferric iron ions were present in olivine crystals and the amorphous matrix, respectively. The discovery of both metallic and ferric iron in the amorphous matrix of Chang’E-5 lunar soil offers new insights regarding the disproportionation reaction of Fe 2+ on the lunar surface. This study demonstrates that the combination of FIB, AES, and TEM-EELS is an effective and precise approach for analyzing the valence states of iron-bearing phases in lunar soil, which can be extended to other extraterrestrial samples and other multivalent elements.
期刊介绍:
The ATOMIC SPECTROSCOPY is a peer-reviewed international journal started in 1962 by Dr. Walter Slavin and now is published by Atomic Spectroscopy Press Limited (ASPL). It is intended for the rapid publication of both original articles and review articles in the fields of AAS, AFS, ICP-OES, ICP-MS, GD-MS, TIMS, SIMS, AMS, LIBS, XRF and related techniques. Manuscripts dealing with (i) instrumentation & fundamentals, (ii) methodology development & applications, and (iii) standard reference materials (SRMs) development can be submitted for publication.