Nobuyuki Mori1, Haruo Hongou2 and Keisaku \=Ogi1
1Faculty of Engineering, Kyushu University, Fukuoka
The wettability and the interaction between liquid Sn or Sn-Cu alloys and solid Cu-Nb two-phase alloys, which are in use to make in-situ Cu-Nb3Sn superconducting composites, were investigated by the sessile drop method in vacuum at temperatures from 523 to 903 K.
Wetting angle of liquid Sn or Sn-Cu alloys to solid pure Nb, Cu-30%Nb, 8%Nb alloys, or pure Cu substrate was affected by the wetting temperature, time, composition of solid Cu-Nb substrate or liquid Sn alloy, and additional element of Ti. Especially, in spite of a significant reaction of substrate with Sn, the fraction of Nb and the Cu phase in solid substrate was considered as a controlling factor in wetting behavior of liquid Sn or Sn alloy, and Cassie's equation of wetting angle for the composite surface of the Cu and Nb phases could be applied approximately. The variations in the composition and thickness of the interfacial reaction zone were clarified up to 6 h at temperatures of 643, 823, and 873 K by using solid-liquid diffusion couple type specimens.
wettability, contact angle, liquid tin, copper-niobium alloys, liquid tin-copper alloy, superconducter, interfacial reaction, composites
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