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TY - THES AU - Schneider, Andre TI - Metal dusting PB - Rheinisch-Westfälische Technische Hochschule Aachen VL - Habilitationsschrift CY - Aachen M1 - RWTH-2022-01862 SP - 1 Online-Ressource : Diagramme PY - 2020 N1 - Veröffentlicht auf dem Publikationsserver der RWTH Aachen University 2022 N1 - Habilitationsschrift, Rheinisch-Westfälische Technische Hochschule Aachen, 2020 AB - Metal dusting is a high-temperature corrosion process which attacks iron, low- and high-alloyed steels, and Co- or Ni-based alloys in strongly carburising gas atmospheres with carbon activities aC>> 1in the temperature range 400 to 1000 °C. It occurs in various processes in petrochemical plants, e.g. for catalytic reforming, ammonia, and methanol production, indirect reduction plants and further more. Some examples of failure cases are given in the chapter on industrial relevance. Although numerous studies have been performed during the past decades to better understand this high-temperature corrosion process and although various approaches to make components in the above mentioned environments resistant against metal dusting, the according failures still occur. Thus, metal dusting is still an important technical challenge requiring further scientific studies and improved protection concepts. This work gives an overview on the present understanding of the metal dusting mechanisms. It discusses the proposed explanations and shows examples of the variety of corrosion products observed by the numerous researchers in the field. In addition, special investigations on diffusion in iron carbides and also on the constitution of the Fe-C system are discussed. The first part of this work comprises the literature data on metal dusting from the various research groups and also in a few cases from industry. The results of the author of this work and his co-authors are also reviewed and cited. It starts with a general description of carburisation, coking, and metal dusting. Then case studies are discussed to demonstrate the industrial relevance of this high-temperature corrosion process. The following chapters focus on the metal dusting of iron and various Fe-based alloys which are divided into ferritic and austenitic steels. Various results on the effect of sulphur on metal dusting retardation are based on respective studies with iron, but the findings are also relevant for alloyed steels and thus of high importance for the operation of petrochemical units. Metal dusting of Ni-based alloys and also coating developments for the protection against metal dusting are then described. Metallurgical investigations under metal dusting conditions are summarised in the last chapter of the literature review. The second part describes the various studies of the author of this work in detail. The main results of these studies are partly cited in the first part overviewing the according literature. The various co-authors of these studies are mentioned in the preface of this thesis and also in the citations of the literature overview. The first two chapters focus on phase formation and decomposition process during metal dusting. The third chapter is on metal dusting of Fe-X (X = Si, Mo, V) alloys, and the last chapter deals with metal dusting of Fe-Al-based alloys. The most significant contributions to metal dusting and also to the fundamentals of the Fe-C system are achieved by the author of this thesis concerning the following scientific topics:- the initiation of metal dusting of Fe,- the propagation of metal dusting of Fe and the various observed decomposition processes: - formation and decomposition of metastable carbides into iron and carbide particles, - formation of a cementite layer and transformation into an iron layer which subsequently decomposes itself,- the effect of sulphur on the retardation of metal dusting of Fe,- the effect of alloying elements on the metal dusting of Fe-based alloys: - Fe-Al alloys, - and Fe-X (X = Si, Mo, V) alloys, - the constitution of Fe3C,- the thermodynamics of Fe5C2 formation,- the carbon diffusion in Fe3C and Fe5C2,- and the effect of alloying elements on cementite growth in Fe-X (X = Si, Mo, V) alloys. LB - PUB:(DE-HGF)13 DO - DOI:10.18154/RWTH-2022-01862 UR - https://publications.rwth-aachen.de/record/841613 ER -