Verdampfung von Werkstoffen beim Betrieb von Hochtemperaturbrennstoffzellen (SOFC)
type: CreativeWork
description: Due to their high efficiencies and versatility planar solid oxide fuel cells (SOFCs) offer a lot of advantages compared to other fuel cell systems and combustion engines.One of the main problems concerning the development of state of the art planar SOFCs are the occurrence of ageing effects in long term application. To a great deal these effects are caused by the release of volatile Cr-species from metallic interconnects which leads to an inhibition of the electrochemical processes at the cathode resulting in a rapid degradation of the cell performance.A goal in further development of SOFC-systems is the reduction of the operation temperature of the cell from currently 800°C to 700°C and below. For this purpose alternative electrolyte materials with higher oxygen ion conductivities have to be developed. Doped lanthanum gallates have been identified as promising materials. However for these materials a depletion of Ga by vaporization has been observed under anodic conditions which may lead to a destruction of their electrolyte properties. The aim of this work is the study of the vaporization processes leading to the mentioned degradation effects. For this purpose an experimental setup according to the transpiration method has been developed.Concerning the vaporization of chromium the Cr release rates of the main ferritic interconnect alloys, namely Crofer 22 APU, ZMG 232, E-Brite, IT-10, IT-11, IT-14 and Ducrolloy as well as a variety of Ni- and Co-base superalloys and stainless steels with different contents of Al, Si, Ti, Mn, W, Ni and Co were measured at 800°C in air and compared to each other. The alloys that form an upper layer of Cr-Mn-spinel on top of the grown chromia scale showed a reduction of the Cr release by 61-75% compared to pure chromia scales whereas alloys with an outer Co3O4(s) scale had a by more than 90% reduced Cr release. For the former alloys a significant vaporization of Mn under anodic conditions could be detected. On the base of empirical d…
abstract: Due to their high efficiencies and versatility planar solid oxide fuel cells (SOFCs) offer a lot of advantages compared to other fuel cell systems and combustion engines.One of the main problems concerning the development of state of the art planar SOFCs are the occurrence of ageing effects in long term application. To a great deal these effects are caused by the release of volatile Cr-species from metallic interconnects which leads to an inhibition of the electrochemical processes at the cathode resulting in a rapid degradation of the cell performance.A goal in further development of SOFC-systems is the reduction of the operation temperature of the cell from currently 800°C to 700°C and below. For this purpose alternative electrolyte materials with higher oxygen ion conductivities have to be developed. Doped lanthanum gallates have been identified as promising materials. However for these materials a depletion of Ga by vaporization has been observed under anodic conditions which may lead to a destruction of their electrolyte properties. The aim of this work is the study of the vaporization processes leading to the mentioned degradation effects. For this purpose an experimental setup according to the transpiration method has been developed.Concerning the vaporization of chromium the Cr release rates of the main ferritic interconnect alloys, namely Crofer 22 APU, ZMG 232, E-Brite, IT-10, IT-11, IT-14 and Ducrolloy as well as a variety of Ni- and Co-base superalloys and stainless steels with different contents of Al, Si, Ti, Mn, W, Ni and Co were measured at 800°C in air and compared to each other. The alloys that form an upper layer of Cr-Mn-spinel on top of the grown chromia scale showed a reduction of the Cr release by 61-75% compared to pure chromia scales whereas alloys with an outer Co3O4(s) scale had a by more than 90% reduced Cr release. For the former alloys a significant vaporization of Mn under anodic conditions could be detected. On the base of empirical d…
author: Stanislowski, Michael
language: ger
keywords: info:eu-repo/classification/ddc/620, Ingenieurwissenschaften, Festoxidbrennstoffzelle, Verdampfung, Degradation, Chromoxid, Hitzebeständige Legierung, Gallate, Galliumoxide, Alu, Transpirationsmethode, Transpiration method
date published: 2006
date modified: 2026-07-30T19:43:02Z
provider: RWTH Aachen University
publisher: Networked Digital Library of Theses and Dissertations
type: WebPage
source organization: Publikationsserver der RWTH Aachen University