Impacts of Carbon Impurity in Plasmas on Tungsten First Wall
نویسندگان
چکیده
Abstract. In order to study the effect of carbon impurity in plasma on tungsten first wall, hydrogen-carbon mixed ion beam was irradiated to tungsten. It was found that very small amount of carbon (~0.3% or more) significantly enhanced blister formation. According to XPS analysis, all of tungsten atoms in a top surface were combined with carbon atoms to form tungsten carbide (WC) layer (~6 nm thick) in the cases that significant blisters were observed. This layer could enhance diffusion of hydrogen atoms to the bulk, leading to blister formation. In addition, carbon impurity increased hydrogen retention, but the increment of the retention tended to decrease with fluence.
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