Structure of hetero-epitaxial nickel film on iron-substrate by electrodeposition

With special attention to the fine structure of Ni film and the structure of Ni/a-Fe interface, the hetero-epitaxial growth of Ni electrodeposits on polycrystalline a-Fe has been studied mainly by transmission electron microscopy. (1) Ni grows hetero-epitaxially even under a high current density as 500 A/m² on a cleaned substrate surface. (2) The crystallographic orientation relationship between Ni deposits and the substrate a-Fe is almost the same as that of the Kurdjumov-Sachs relationship. (3) the Ni hetero-epitaxial film consists of columnar crystals which grow in the direction and contains dislocations and stacking faults with high density. (4) These defects are introduced in order to decrease the elastic strain caused by the misfit between Ni and a-Fe at the interface. The number of defects decreases with increasing film thickness.