2013 Fiscal Year Final Research Report

Creative Preparation of High-oxidation Resistant Coating on Nb-base Heat-resistant Alloys using Molten-salt Electrodeposition and Self-systematization

Research Project

Project/Area Number	23560860
Research Category	Grant-in-Aid for Scientific Research (C)
Allocation Type	Multi-year Fund
Section	一般
Research Field	Material processing/treatments
Research Institution	Akita University
Principal Investigator	HARA Motoi 秋田大学, 工学(系)研究科(研究院), 教授 (50156494)
Co-Investigator(Kenkyū-buntansha)	FUKUMOTO Michihisa 秋田大学, 工学資源学研究科, 講師 (20343064)
Project Period (FY)	2011 – 2013
Keywords	コーティング / 耐酸化性 / 電析 / 溶融塩 / ニッケルアルミナイド / ニオブ基合金 / 自己組織化
Research Abstract	Coatings of Ni aluminide/Ni bilayer on Nb-W and Nb-W-Mo alloys were prepared by the electrodeposition of Al using a molten salt electrolyte after the Ni electrodeposition. The coating specimen with a thin Ni layer showed a vigorous oxidation during the initial period. On the contrary, the coating specimen with a thick Ni layer showed a high oxidation resistance. For the coating specimen with a thick Ni layer, intermediate layers consisting of Ni-Nb alloys were formed by the diffusion of the Ni layer and the alloy substrate during the oxidation test. These intermediate layers contributed the maintenance of a high concentration of Al in the surface layer and the suppression of spallation of the layers, leading to the improvement in the oxidation resistance of the coating.