ABSTRACT
The identification and fabrication of suitable interconnect materials is a major challenge in the development of solid oxide fuel cells (SOFCs) [1, 2]. The primary function of the interconnect is to carry electrical current from the electrochemical cell to the external circuit, so the inteconnect material must have good electrical conductivity. In addition, the interconnect must be chemically and mechanically stable for operation at high temperatures for long periods of time. This is especially challenging because the interconnect is exposed to both oxidizing conditions at the cathode and reducing conditions at the anode. Thus, interconnect materials should not undergo significant dimensional changes with changes in either temperature or oxygen partial
4.1 Introduction ................................................................................................... 179 4.1.1 Interconnect Requirements ............................................................... 179 4.1.2 Materials Used for Interconnects ...................................................... 180
4.2 Ceramic Interconnects .................................................................................. 180 4.2.1 Stability ............................................................................................. 180
4.2.1.1 Volatilization ...................................................................... 181 4.2.1.2 Chemical Compatibility ..................................................... 181
4.2.2 Transport Properties .......................................................................... 181 4.2.3 Physical Properties ............................................................................ 184
4.2.3.1 Dimensional Changes ......................................................... 184 4.2.3.2 Mechanical Properties ........................................................ 185
4.2.4 Processing ......................................................................................... 186 4.3 Metallic Interconnect Materials .................................................................... 187
4.3.1 Candidate Alloys ............................................................................... 187 4.3.2 Surface Stability: Oxidation and Corrosion ...................................... 190 4.3.3 Chromia Scale Volatility and Cell Poisoning ................................... 195 4.3.4 Chemical Compatibility .................................................................... 196
4.4 Protective Coatings for Metallic Interconnects ............................................ 198 4.5 Summary and Conclusions ...........................................................................202 References ..............................................................................................................203
