No abstract

No abstract

No abstract

High temperature polymer membrane fuel cells (HTPEMFCs) are promising devices for future mobile applications. To minimize phosphoric acid migration from the membranes and to reduce the total stack weight and size metallic bipolar plates are a promising alternative. So far only very few published results are available on the use of metallic bipolar plates in HTPEMFCs. During this work a single test cell was equipped with metallic endplates to investigate the possibility of using metallic bipolar plates in HTPEMFC stacks. Furthermore we tried to simulate the environments present in an HTPEMFC by furnace exposures in an attempt to develop a simplified test method for accelerated corrosion of bipolar plate materials. It was found that the performance of the HTPEM test cell decreased by about 15 µV h−1. More corrosion products were seen on the cathode side samples, whereas on the anode side sample the corrosion attack of the steel was more severe. These results were successfully replicated in simulated furnace experiments.

No abstract

No abstract

This study investigates the corrosion performance of selected ferritic steels in simulated solid oxide electrolysis cell (SOEC) environments for exposure times up 500 h. Ferritic steels have many properties that are desirable for interconnects but suffer from oxidation and chromium evaporation over time. Four different FeCr alloys have been exposed in different concentrations of dry O2 (anode side) and in 34% H2O -3% H2-Ar (cathode side) at 850°C and gravimetrical measurements have been performed to study oxidation rates. Chromium evaporation has been measured and compared for the oxygen containing environments. Chromium evaporation was found to vary largely with oxygen partial pressure, while the oxidation rate of the steels did not vary substantially in the different oxygen partial pressures. Differences in oxidation behavior of the steels were observed between the exposures in dry O2 and in 34% H2O -3% H2 -Ar. Both reduced and increased oxidation rates were observed in the cathode side atmosphere compared to the oxygen side atmosphere for different materials.

In previous studies an extreme dual atmosphere effect on the airfacing side of AISI 441 at 600°C was observed. However indications showed that pre-oxidation of the material might have a beneficial effect on the corrosion resistance in dual atmosphere. To examine this further we pre-oxidized AISI 441 samples for 0 min, 11 min, 45 min, 180 min and 280 min and subsequently exposed these at 600 °C for 500 h under dual atmosphere conditions. Photographs of the air-facing sides were taken throughout exposure to monitor the corrosion behavior. SEM analysis was performed on all samples after exposure.