Influence of Bath Composition on Tensile Ductility in Electrodeposited Bulk Nanocrystalline Nickel

We investigated the influence of bath composition on characteristics in an electrodeposited bulk nanocrystalline Ni (nc-Ni). This study was aim to establish the fabrication process of bulk nc-Ni with good tensile property. The bulk nc-Ni was electrpdeposited from a sulfate bath and a sulfamate bath. The nc-Ni was evaluated for microstructure and mechanical properties, such as microhardness, tensile strength. As a result, bulk nc-Ni obtained from a sulfamate bath exhibited enhanced tensile property (ultimate tensile strength of 1006 MPa and ductility of 8.8%) compared to that obtained from a sulfate bath. Dimple pattern was observed in fracture surface of bulk nc-Ni obtained from a sulfamate bath. However, dimple pattern and brittle fracture surface were observed in bulk nc-Ni obtained from a sulfate bath. We consider the ductility of electrodeposited nc-Ni was influenced by internal stress generated from electrodepostion. These experiments and analyses suggest that it is important to control internal stress on fabrication of bulk nc-Ni with high tensile strength and good ductility. [doi:10.2320/matertrans.M2010279]