Oxidation Behavior and Chromium Vaporization of Ion Implanted Crofer22APU

Abstract

Crofer 22APU, used for interconnects in solid oxide fuel cells (SOFCs), is studied to improve its oxidation resistance and to suppress chromium vaporization from the oxide scales. Carbon and nitrogen were implanted on the plate surface by the ion implantation method. These samples were subjected to oxidation at 800 degrees C for 500 hours. Oxidation kinetics was determined by measuring weight gains at regular time intervals. Experiments to determine chromium volatility from the samples were conducted at 800 degrees C in a tube furnace in flowing air. The chromium vapors were collected on a silicon wafer and Rutherford Backscattering Spectroscopy (RBS) was used to measure the chromium vaporization rates. ASR measurements were also carried out on the samples. AES, SEM/EDS and TEM were used to characterize the initial and oxidized surface of the samples. The ion-implanted samples show significantly less chromium vaporization rate than the unimplanted samples.