AVS 47th International Symposium
    Surface Engineering Tuesday Sessions
       Session SE-TuM

Paper SE-TuM10
A Novel Interface Modification Technique Applied from the Top of a Coated Layer

Tuesday, October 3, 2000, 11:20 am, Room 201

Session: Interface Engineering and Graded Films: Structure and Characterization
Presenter: M. Yoshitake, National Research Institute for Metals, Japan
Authors: M. Yoshitake, National Research Institute for Metals, Japan
Y.-R. Aparna, National Research Institute for Metals, Japan
K. Yoshihara, National Research Institute for Metals, Japan
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A technique to modify interface after the formation of interface is desired either from a process requirement or because of the change of material use with time. A novel technique to form an intermetallic compound at the interface between coated layer and substrate by depositing a chosen metal film on the top of a coated layer is presented. Based on the property of the intermetallic compound, an interface is modified. Experimentally, the diffusion and interfacial reaction of specimens with top-film/middle-film/substrate structure were investigated. With proper choice of top-film element, top-film element diffuses inside without detectable reaction with middle-film and concentrate at the interface between middle-film and substrate followed by intermetallic compound formation. We discuss conditions for obtaining above phenomena and general guide for a choice of top-film element is presented. Key factors are (1)segregation tendency of top-film element on middle-film metal, (2)activation energy of diffusion of top-film element in middle-film and in substrate and (3)formation of intermetallic compound between top-film metal and substrate in phase diagram. The examples of intermetallic compound formation by the diffusion of top-film element are given in Ti-film/Nb-film/Cu-substrate, Fe-film/Nb-film/Ti-substrate and other combinations.