Study on lotus-type porous copper electroplated with a Ni coating on inner surface of pores

Deposition of Ni coating on inner surface of pores was attempted by electroplating for lotus-type porous copper with pore size of 0.6 mm and pore length of 6 mm. The surface morphology, thickness, thickness distribution along the pore length, and phase composition of the coating were characterized. It is proven that the Ni coating with a polycrystalline structure can be deposited on the inner surface of the pores with length/diameter of 10 for lotus-type porous copper by agitating the electroplating solution properly during the process. It is indicated that the coating thickness distributes uniformly along the pore depth and is about 4–5 μm. Furthermore, the mechanical properties including vicker hardness, compressive yield strength and absorbed energy ability of the electroplated porous copper were evaluated. It is found that the mechanical properties are improved significantly after depositing the nickel coating inside pores of the lotus-type porous copper. Among them, 0.2% yield stress increases from 22.96 to 30.15 MPa, while absorbed energy per volume from 60.83 to 96.01 MJ/m3 when compressed to strain of 80%, which is attributed mainly to the Ni coating as an obstacle to dislocation slip during deformation and its strengthening effect for the higher strength, and the good adhesion to the pore wall of the porous copper.