Corrosion resistance of ZnNiP+Ni composite coatings

Abstract

Zn-Ni-P+Ni composite coatings were prepared by embedding nickel particles into Zn-Ni-P alloy using ammonia solution in which Ni powder was suspended by stirring. Such coatings have been deposited on a 0H18N9 stainless steel substrate under galvanostatic conditions (j = −40 mA cm −2 ), and at a temperature of 293 K. In order to investigate corrosion properties of the as-deposited and annealed (593 K for 2 h in argon atmosphere) Zn-Ni-P+Ni composite coatings in 5% NaCl environment potentiodynamic technique and electrochemical impedance spectroscopy (EIS) were used. It was stated that thermal treatment strongly improved the corrosion parameters of the examined Zn-Ni-P+Ni composite coatings, and also that better corrosion properties result from i) improved corrosion properties of the oxide layer; and ii) the presence of new γ Ni 5 Zn 21 phase in composite matrix.

Cu/Ni/Au multilayers by electrochemistry: A crucial system in electronics - A critical review

“…those that can be deposited individually and those that can be only codeposited. The former group consists of metals that are much nobler than Ni, like Ag [54][55][56][57] and Cu [58][59][60][61][62][63][64][65][66][67][68]; metals that have similar standard potentials, such as Co [69][70][71][72][73][74][75][76] and Sn [77][78][79][80][81][82][83][84][85]; and metals that are more cathodic, like Cr [86,87], Zn [88][89][90][91][92][93][94][95][96][97][98][99][100] and Mn [101]…”

“…To avoid this precipitation, sodium citrate and ammonium chloride are usually added to the deposition bath[90]. Deposition of Ni-Zn alloys is possible in both acidic[91][92][93]96] and basic[89,90] baths. The anomalous deposition of Zn and Ni ions is reported to happen in baths with pH below 9[90].…”