This study investigated the microstructural development of an electrodeposited Ni layer formed from an additive-free Watt's bath. The major texture component of the electrodeposited Ni layer is strong < 110 > fiber. The electrodeposited Ni layer consists of epitaxial regions with a thickness of about 100 nm and fine columnar grains extending along the growth direction. The fine columnar grains contain a high density of twins parallel to the growth direction. These twins were formed at side {111} facets during the lateral growth of the electrodeposited Ni layer. We surmise that the twins formed in order to change the orientation so that the energy of boundary between the existing grain, on which twin related grains nucleated, could be reduced. (c) 2010 Elsevier B.V. All rights reserved.