Linköping University| Department of Physics, Chemistry and Biology Master of Science Thesis, 30 ETCS| Applied Physics Spring 2018| LITH-IFM-A-EX—18/3572—SE Surface Analysis of Aluminium Alloy AA3003 Exposed to Immersion Corrosion Test: An X-Ray Photoelectron Spectroscopy Study Evelina Hansson Supervisors: Lars-Åke Näslund Gränges R&I Grzegorz Greczynski IFM, Linköping University Examiner: Per Eklund IFM, Linköping University Upphovsrätt Detta dokument hålls tillgängligt på Internet – eller dess framtida ersättare – under 25 år från publiceringsdatum under förutsättning att inga extraordinära omständigheter uppstår. Tillgång till dokumentet innebär tillstånd för var och en att läsa, ladda ner, skriva ut enstaka kopior för enskilt bruk och att använda det oförändrat för ickekommersiell forskning och för undervisning. Överföring av upphovsrätten vid en senare tidpunkt kan inte upphäva detta tillstånd. All annan användning av dokumentet kräver upphovsmannens medgivande. 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Subsequent transfers of copyright cannot revoke this permission. All other uses of the document are conditional upon the consent of the copyright owner. The publisher has taken technical and administrative measures to assure authenticity, security and accessibility. According to intellectual property law the author has the right to be mentioned when his/her work is accessed as described above and to be protected against infringement. For additional information about the Linköping University Electronic Press and its procedures for publication and for assurance of document integrity, please refer to its www home page: http://www.ep.liu.se/. © Evelina Hansson ii Abstract Corrosion is a common issue which must be accounted for when designing all metal products in our society. Many factors need to be considered when new alloys are created, and further knowledge of the corrosion process would be of great use for companies worldwide. The purpose of this thesis was to investigate if X-ray Photoelectron Spectroscopy, XPS, can be used to characterise and quantify corrosion products. With the goal to develop a method that can be used for further studies to increase our understanding of the corrosion process. Aluminium alloy AA3003 was subjected to an immersion corrosion test in an acidified salt solution for different periods of time and the produced chemical compounds were characterised using XPS. The results revealed a direct connection between corrosion time and formed product, which after characterisation proved to be aluminium hydroxide, Al(OH)3. It was concluded that XPS can be used for corrosion studies and is a method that shows great potential and should be further developed. Sammanfattning I metallindustrin är korrosion ett ständigt förekommande problem som måste tas i beaktande vid design av metallprodukter. Många faktorer är avgörande när nya legeringar utvecklas och en djupare kunskap om korrosionsprocessen och dess mekanismer är av stort värde för företag världen över. Syftet med detta examensarbete var att undersöka huruvida röntgen-fotoelektron- spektroskopi, XPS, kan användas för att kvalitativt och kvantitativt karakterisera de korrosionsprodukter som bildas vid korrosion. Med målet att presentera en metod som kan användas för att vidare undersöka och öka vår förståelse för korrosionsprocessen. Aluminiumlegering AA3003 utsattes för accelererad korrosion i en surgjord saltlösning under varierande tid och korrosionsprodukter karakteriserades med XPS. Resultatet påvisade direkt korrelation mellan korrosionstid och mängd produkt. Korrosionsprodukten visade sig vara aluminiumhydroxid, Al(OH)3, och med det i åtanke kunde slutsatsen dras att XPS kan användas vid studier av korrosion. Den utvärderade metoden visar stor potential och detta examensarbete öppnar upp för vidare forskning som kan komma att öka förståelsen för korrosionsprocessen och hur den kan kontrolleras. iii iv Acknowledgements This master thesis was performed at Linköping University in cooperation with Gränges R&I during the spring of 2018. First, I would like to express my sincere gratitude to the company for the opportunity as well as to all my colleagues for a warm welcome and your contribution to the project and its results. I am especially grateful for the assistance in performing the corrosion tests, the SEM and XPS measurements, as well as the work of the metallurgists in preparing the alloy. Finally, I would like to thank family and friends for all your support and encouragement throughout the years. Special thanks to: Lars-Åke Näslund, supervisor at Gränges R&I: For all guidance and help throughout the entire project. Per Eklund, examiner IFM: For providing feedback. Louise Bäckström: For proof reading and giving feedback on the report. Jonas Hartman: For proof reading and support. Linköping, June 2018 Evelina Hansson v vi Table of Contents 1 Introduction ..................................................................................................................... 1 1.1 Aims and Goals ................................................................................................................. 1 1.2 Background ........................................................................................................................ 1 1.2.1 Gränges Sweden AB ....................................................................................... 1 1.2.2 Aluminium ....................................................................................................... 2 1.2.3 Aluminium Alloy AA3003 ............................................................................... 5 1.2.4 Corrosion ........................................................................................................ 6 1.3 Related Work ..................................................................................................................... 8 1.4 Limitations ......................................................................................................................... 8 1.5 Problem Statement ............................................................................................................. 8 1.6 Report Structure ................................................................................................................. 9 2 Theory ............................................................................................................................. 11 2.1 Corrosion Tests ................................................................................................................ 11 2.1.1 SAPA Technology Immersion Corrosion ...................................................... 11 2.1.2 Sea Water Acetic Acid Test ........................................................................... 11 2.1.3 Total Immersion Corrosion Potential ........................................................... 12 2.2 Techniques for Analysis .................................................................................................. 12 2.2.1 Scanning Electron Microscopy ..................................................................... 12 2.2.2 Energy Dispersive Spectroscopy .................................................................. 13 2.2.3 X-Ray Photoelectron Spectroscopy .............................................................. 14 2.3 Analysis of X-Ray Photoelectron Spectroscopy Spectra ................................................ 15 2.3.1 Quantification ............................................................................................... 16 2.3.2 Band Bending................................................................................................ 16 2.4 The Aluminium Spectrum ............................................................................................... 17 vii 2.5 Expected Corrosion Products .......................................................................................... 19 3 Method ........................................................................................................................... 23 3.1 Sample Preparation ......................................................................................................... 23 3.1.1 Fabrication of Alloy AA3003 ....................................................................... 23 3.1.2 Brazing Simulation ....................................................................................... 23 3.1.3 Corrosion Tests ............................................................................................ 24 3.1.4 Preparation of Reference Samples ..............................................................