Effects of Current Mode and Electrodes on the Properties of Electroplated Fe-Ni Invar Alloy

Fe-Ni alloy was electroplated at various conditions, varying current mode and anode type to investigate the effects of them on the deposits. In pulse plating, Ni contents of deposits was lowered with increasing peak current. In addition, the compositional uniformity in deposits along with their thickness was increased compared to when using direct current due to anomalous property of Fe-Ni electroplating. On the other hand, the deposits with Ni anode (soluble anode) showed high Ni content than with DSA (inert anode) because of the concentration of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Ni}^{2+}$</tex> in the bath was increased as the Ni anode was dissolved during electroplating. The potential monitoring and <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{pH}$</tex> analysis of bath exhibited that oxidation of <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Fe}^{2+}$</tex> to <tex xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">$\text{Fe}^{3+}$</tex> was only occurred on DSA.