• 제목/요약/키워드: 결정질

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Effect of Current Density on the Crystal Structure of Ni-W Alloys Prepared by Electrodeposition (Ni-W 합금도금의 결정구조에 미치는 전류밀도의 영향)

  • Kim, Won-Baek;Lee, Cheol-Gyeong;Lee, Jae-Cheon;Seo, Chang-Yeol
    • Korean Journal of Materials Research
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    • v.8 no.10
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    • pp.898-904
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    • 1998

  • Ni-W alloys containing 10 to 50wt% W were prepared by electrodeposition. Tungsten content in the alloy increased with current density. X-ray diffraction analysis revealed that the alloy was crystalline phase when deposited at current densities lower than 50mA/${cm}^2$. Their crystal structure transformed to amorphous at higher current densities. In terms of tungsten content, the crystal -+ amorphous transition occurred at 40-46wt% which was identified by the 3 fold increase in the width of a diffraction peak. The lattice parameter of crystalline phase increased with W upto 40wt% which is higher than the solubility limit of W (about 30wt%) in Ni. Therefore, the alloys are considered to be Ni solid solution supersaturated with W. The amorphous Ni-W alloys were recrystallized by annealing them at temperatures over $400^{\circ}C$. This was evidenced by the appearance a strong [ 11 11 annealing texture. The supersaturated W was precipitated during the annealing at over $800^{\circ}C$. The current-density dependence of W content and crystallinity was utilized to produce alternating layers of crystalline (30wt% W) and amorphous (50wt%) phases which may exhibit unique mechanical and corrosion properties.

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