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

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 Be2C was formed on both sample surfaces by vacuum heating above 600 degrees C. Thermal desorption spectroscopy showed that a large amount of hydrogen molecules was desorbed from the carbon film containing hydrogen above 600 degrees C. Kinetic measurements of Be2C growth revealed that the rate is controlled by a random nucleation process. The SIMS measurements also demonstrated evidence of Be2C formation by detecting BeC-(M/e = 21). Hydrogen atoms captured by Be2C however: were not observed, suggesting that Be-carbide has little ability to capture/trap hydrogen isotope atoms. (C) 1997 Elsevier Science S.A.