title: Enhanced electrical conductivity and hardness of silver-nickel composites by silver-coated multi-walled carbon nanotubes.
abstract: We investigated electrical conductivity and Vickers hardness of Ag- and Ni-based composites prepared by powder metallurgy involving spark plasma sintering. The starting composition was Ag:Ni = 61:39 vol%, which provided an electrical conductivity of 3.30 × 10(5) S cm(-1) and a hardness of 1.27 GPa. The addition of bare multi-walled carbon nanotubes (MWNTs, 1.45 vol%) increased hardness (1.31 GPa) but decreased electrical conductivity (2.99 × 10(5) S cm(-1)) and carrier mobility (11 cm(2) V(-1) s(-1)) due to the formation of Ni3C in the interface between the MWNTs and Ni during spark plasma sintering. The formation of Ni3C was prevented by coating the surface of the nanotubes with Ag (nAgMWNTs), concomitantly increasing electrical conductivity (3.43 × 10(5) S cm(-1)) and hardness (1.37 GPa) of the sintered specimen (Ag:Ni:nAgMWNTs = 59.55:39:1.45 vol%). The electrical contact switching time (133 357) was also increased by 30%, demonstrating excellent feasibility as electrical contact materials for electric power industries.
authors.affiliation: Department of Energy Science, Sungkyunkwan University, Suwon, 440-746, Korea.
authors.forename: Dongmok
authors.initials: D
authors.lastname: Lee
authors.forename: Jeonghyun
authors.initials: J
authors.lastname: Sim
authors.forename: Wonyoung
authors.initials: W
authors.lastname: Kim
authors.forename: Chuldong
authors.initials: C
authors.lastname: Moon
authors.forename: Wookdong
authors.initials: W
authors.lastname: Cho
authors.forename: Seunghyun
authors.initials: S
authors.lastname: Baik