Basic study on the modification of vacuum plasma sprayed tungsten coating by friction stir processing

2016 Fiscal Year Final Research Report

• Project/Area Number: 26289360
• Research Category: Grant-in-Aid for Scientific Research (B)
• Allocation Type: Partial Multi-year Fund
• Section: 一般
• Research Field: Nuclear fusion studies
• Research Institution: National Institutes for Quantum and Radiological Science and Technology (2016); Japan Atomic Energy Agency (2014-2015)
• Principal Investigator: Tanigawa Hiroyasu 国立研究開発法人量子科学技術研究開発機構, 核融合エネルギー研究開発部門 核融合炉構造材料開発グループ, グループリーダー (50354668)
• Co-Investigator(Kenkyū-buntansha): 渡邊 誠 国立研究開発法人物質・材料研究機構, 先進高温材料ユニット, 主幹研究員 (00391219) ; 黒田 聖治 国立研究開発法人物質・材料研究機構, 先進高温材料ユニット, ユニット長 (50354220) ; 小沢 和巳 国立研究開発法人日本原子力研究開発機構, 核融合研究開発部門 六ケ所核融合研究所, 任期付研究員 (80613330)
• Co-Investigator(Renkei-kenkyūsha): FUJII Hidetoshi 大阪大学, 接合科学研究所, 教授 (00247230) ; MORISADA Yoshiaki 大阪大学, 接合科学研究所, 教授 (00416356) ; ARAKI Hiroshi 物質・材料研究機構, 主幹エンジニア (90354349) ; EZATO Kohichiro 量子科学技術研究開発機構, 核融合エネルギー研究開発部門, 上席研究員 (30354624) ; SEKI Yoji 量子科学技術研究開発機構, 核融合エネルギー研究開発部門, 主幹研究員 (00469793)
• Project Period (FY): 2014-04-01 – 2017-03-31
• Keywords: 摩擦撹拌処理 / 耐熱皮膜 / タングステン / 真空溶射 / ウオームスプレー法 / 粉末床溶融結合法

Outline of Final Research Achievements

Tungsten (W) is the primary candidate material as a plasma facing material in fusion devices. The vacuum plasma spray (VPS) technique has been investigated, but the issues are its low thermal conducitivty and low strength of VPS-W mainly caused by the porous structure of VPS-W. In order to solve these issues, friction stir processing (FSP) was applied on VPS-W, and it was suggested that FSP can contribute to significant improvement both in mechanical and thermal properties of VPS-W coating. Hardness test over FSPed VPS-W layer revealed that the hardness of W becomes equivalent to or higher than that of bulk W. Thermal conductivity was about 80% of bulk W at 200°C, but it becomes equivalent to that of bulk W over 800°C. Warm Spray (WS) method and Selective Laser Melting (SLM) method have been examined as the potential new technique as the W coating, and it turned out that SLM can form a decent thickness of W coating, but with a larger porousness.

Free Research Field

核融合材料開発