Metal Sputtering and Hydrogen Retention in Metal-Carbon Composite Layer Materials

The sputtering of metal atoms and the retention and release of hydrogen isotopes in metal-carbon composite layer materials are discussed. The criteria for suppression of metal sputtering are derived on the basis of the concentration of carbon atoms segregated at the surface, which is calculated taking into account segregation and dissolution at the surface and at the interface as well as diffusion. Data on the ion flux dependence of the sputtering yield of metal from different metal-carbon systems are presented, and the critical flux and thickness required for suppression of metal sputtering are discussed. Furthermore, data on retention and release of implanted hydrogen isotopes are presented and compared with those for graphite.