峰值电流密度对脉冲镀镍钴合金纳米镀层机械性能的影响

研究了峰值电流密度对脉冲镍钴合金纳米镀层的成分、晶粒尺寸、显微硬度、抗拉强度的影响.结果发现:在一定范围内,峰值电流密度的增大,可以降低镀层钴含量、表面粗糙度和晶粒尺寸,使菜花胞状结构更明显,提高镀层显微硬度(最高可达600 kg/mm2)和抗拉强度(最高可达1 200 MPa).然而,峰值电流密度太大又会使显微硬度和强度下降.与采用类似方法制得的纯镍纳米镀层相比,镍钴镀层的显微硬度并未明显升高.这说明在该纳米材料中,固溶强化效果并不很明显,而以细晶强化为主.

Effect of peak current density on mechanical properties of nanocrystalline nickel-cobalt alloy coating produced by pulse electrodeposition

The effect of peak current density on the composition, grain size, microhardness and tensile strength of nanocrystalline Ni-Co alloy coating prepared by pulse electrodeposition was studied.The results showed that the increase of peak current density in a certain range decreases the Co content, surface roughness, and grain size of deposit, makes the colony-like cellular structure more obvious, and improves the microhardness(up to a maximum of 600 kg/mm2) and tensile strength(up to a maximum of 1 200 MPa).However, over-high peak current density can lead to a decrease in microhardness and tensile strength.As compared to nano-Ni deposit, the microhardness of Ni-Co alloy is slightly increased, indicating that the refinement hardening is dominant in nanocrystalline materials over the solution hardening.