Properties and microstructure of nickel electrodeposited from a sulfamate bath containing ammonium ions
Source: Journal of Applied Electrochemistry, Volume 31, Number 8, August 2001 , pp. 925-933(9)
Abstract:A 70 μm thick Ni layer was electrodeposited from a sulfamate bath containing various amounts of ammonium ions onto a copper plate. The detailed microstructure of the Ni deposits was characterized using a plane-view and cross-sectional transmission electron microscopy (TEM). The textures of the Ni deposits were also determined using conventional X-ray diffraction. Experimental results indicated that ammonium ions suppressed the lateral growth of Ni deposits and favoured out growth, thus leading to the growth of [1 1 0] and [3 1 0] oriented deposits. A structural refinement effect was observed after ammonium ions were added to the sulfamate bath. Ammonium ions also increased the internal stress and hardness of the deposits. A general Hall–Petch relationship was observed for the dependence of deposit hardness on the average grain size of the Ni deposits. The adsorption of atomic hydrogen and the polar NH_3 molecule explains the effect of ammonium ions on the electrocrystallization of Ni.
Keywords: ammonium ions
Document Type: Regular Paper
Affiliations: 1: Department of Mechanical Engineering, Da-Yeh University, Dah-Tsuen, Changhua 51505, Taiwan, ROC 2: Steel and Aluminum Research and Development Department, Taiwan, ROC 3: New Materials Research and Development Department, China Steel Corporation, Hsiao-Kung, Kaohsiung 81233, Taiwan, ROC
Publication date: August 2001