Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
5361550 | Applied Surface Science | 2008 | 5 Pages |
Abstract
Cobalt content, grain size, microhardness and tensile strength of nanocrystalline Ni-Co deposits produced from a solution containing saccharin and cobalt sulfate at constant electrodeposition conditions (pulse on-time Ton at 1 ms and pulse off-time Toff at 15 ms) but varying the peak current density Jp were investigated. It is found that an increase in Jp makes the deposit Co content lower, colony-like morphology more obvious, grain size smaller, and hardness and tensile strength higher. All of the facts are believed to result from the higher overpotential and nucleation rates caused by the Jp increase. But its further increase could lead to reduction in the hardness and tensile strength. Peak current densities in the range of 100-120 A dmâ2 are recommended for the preparation of nanostructured Ni-Co alloy deposits with grain sizes in the range of 15-20 nm, containing 7-8% Co, possessing hardness of 590-600 kg mmâ2 and tensile strength of 1180-1200 MPa-significantly higher than the strength of pure nickel deposit which is produced by the similar method and gets similar grain size.
Keywords
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Physical Sciences and Engineering
Chemistry
Physical and Theoretical Chemistry
Authors
Yundong Li, Hui Jiang, Weihua Huang, Hui Tian,