Chemical compound formation and its analysis in the beryllium-carbon binary system at elevated temperatures

Abstract

Changes in the chemical states of co-existing layers of Be and C with vacuum heating were studied by means of X-ray photoelectron spectroscopy (XPS), secondary ion mass spectroscopy (SIMS) and X-ray diffractometry (XRD). Two different samples were prepared. One was a Be plate covered with evaporated carbon film, [C/Be] and the other was a Be plate covered with carbon film containing hydrogen which was deposited by ethylene plasma, [C(H)/Be]. The XPS and XRD measurements disclosed that Be 2C was formed on both sample surfaces by vacuum heating above 600°C. Thermal desorption spectroscopy showed that a large amount of hydrogen molecules was desorbed from the carbon film containing hydrogen above 600°C. Kinetic measurements of Be 2C growth revealed that the rate is controlled by a random nucleation process. The SIMS measurements also demonstrated evidence of Be 2C formation by detecting BeC − (M/e=21). Hydrogen atoms captured by Be 2C, however, were not observed, suggesting that Be-carbide has little ability to capture/trap hydrogen isotope atoms.