Electrochemical studies of nickel deposition from aqueous solution in super-gravity field

Abstract

The effect of super-gravity on electrochemical deposition of nickel from aqueous solution was studied. The SEM pictures show that the microstructure of nickel film deposited under the super-gravity condition is finer and more uniform compared with that obtained in normal gravity condition, and the crystal grains diminish with the increase of super-gravity coefficient. The XRD patterns indicate that the arrangement of crystalline grains of nickel film deposited under the super-gravity field is more regular, and the crystalline grain sizes decrease with the increase of super-gravity coefficient. Toughness, tensile stress and hardness of the nickel film are markedly raised with the increase of super-gravity coefficient, and hydrogen content in the nickel film decreases with the increase of super-gravity coefficient. From the polarization curves of hydrogen evolution reaction under the super-gravity condition, a significant reduction of over-potential on electrode was found when current density increased. The process of hydrogen evolution reaction was enhanced under the super-gravity condition. The electro-deposition rate, the microstructure and properties of deposited nickel film under super-gravity condition were still affected by the relative orientation between inertia force and depositing surface. It is favorable to gain the nickel film with better mechanic properties when inertia force orientates vertically towards depositing surface.

Progress toward Electrochemistry Intensified by using Supergravity Fields

“…Ni and Fe foils were electrodeposited under a supergravity field in our previous studies . It was found that the grains of all metal foils were refined by using a supergravity field.…”

“…Under a supergravity field, the bubbles moved with an arc, owing to inertia. The bubble separation went through point contact, and the contact time of the bubbles on the electrode surface was shortened under a supergravity field, so that the growth of bubbles was inhibited. The critical radii ( r G ) of bubbles and the driving force ( F G ) for bubble separation under a supergravity field are given as Equations (5) and : …”

Structure and mechanical properties of iron foil electrodeposited in super gravity field

“…Metallization of the silicon for microelectronic applications can be significantly enhanced by employing a super gravity field during the deposition process [25]. Furthermore, the super gravity field influences the morphology and the microstructure of deposits strongly [25][26][27][28]. For example, Cu metallization of silicon in the super gravity fields had smoother and denser surfaces [25].…”

“…In order to improve the properties of iron foil, finer grains should be obtained during electrodeposition. The advantage of super gravity field on nickel electrodeposition from aqueous solutions has been observed [26]. It was found that both grain size and hydrogen content in nickel foil decreased with the increased gravity coefficient [26].…”

Effects of gravity on the electrodeposition and characterization of nickel foils

“…Therefore, it is significant to study the effects of gravity on the metal electrodeposition process, structures and properties of deposits. The applications of the super gravity field to the electrochemical deposition have received great interest [7][8][9][10][11][12]. The experiments in the super gravity field can be easily and cheaply achieved by centrifuges.…”