Zinc nickel deposits produced from acid chloride electrolytes contain Y phase Ni_5Zn_(21) when nickel content is 12 to 15 percent by weight. Ammonium chloride electrolytes produce deposits with crystal orientations versus current density that are opposite of that seen with a potassium chloride electrolyte. The significance of this on deposit properties, such as stress and elongation, and the ability to post-plate form articles need further investigation. Ammonium chloride electrolytes will produce alloys with nickel content versus current density distribution that is more favorable for commercial applications. In fact, ammonium chloride zinc nickel baths are in commercial operation in both rack and barrel applications. However, where there are restrictions on the use-of ammonium chloride, commercially viable potassium-chloride-based electrolytes are available. In order to control the alloy content in extremely low current density areas, a mild complexor is preferred to control the alloy deposition. While non-complexed potassium chloride processes have been made commercially available, the high nickel content alloy obtained in extremely low current density areas and the narrow temperature operating range required, do not make these electrolytes attractive for commercial operation.
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