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Development and Performance of Tungsten-Coated Graphitic Foam for Plasma-Facing Components

Publication Type
Journal Name
Fusion Science and Technology
Publication Date
Page Numbers
551 to 557

High-density graphitic foam is an ideal low-Z plasma facing material for D-D plasma experiments where tritium codeposition is not an issue. However, the graphitic foam like all carbon suffers from the precipitous drop in thermal conductivity at high temperatures, >600 oC. To mitigate these problems, functionally graded layers of tungsten can be deposited to a thickness of 2-4 mm onto the plasma side of the foam using chemical vapor deposition (CVD). The graphitic foam then acts as a high-conductivity heatsink at temperatures below 600 oC for the thin high-Z armor coating. The overall component weighs 18x less than a comparable block of tungsten and lacks the CTE joining issues between the CuCrZr tubing and the tungsten. This article discusses the coating development and characterization and presents the results of recent plasma exposures in W7-X. We also report on the CFD heat transfer modeling and preparations for high heat flux (HHF) testing of the mock-ups. This hybrid PFC consisting of innovative engineered materials may be a cost-effective, actively-cooled solution for the divertors of long-pulse machines like W7-X and WEST.