The Mechanism of Phosphorus Incorporation during the Electrodeposition of Nickel‐Phosphorus Alloys

Abstract

Phosphine was detected and quantified during the electrodeposition ofnickel-phosphorus alloys. The presence of PH3 supports the indirectmechanism of phosphorus incorporation: the phosphorus oxyacid in thebath is reduced to phosphine, which then undergoes a redox reaction withNi2+ to produce both phosphorus and nickel in the elemental form.Phosphine is produced more readily from hypophosphorus acid than fromphosphorus acid. Phosphine production from hypophosphorus acid isfavored by low pH, and facilitated by the presence of nickelous ion. Thelatter effect may result from the release of hydrogen ions in the redoxreaction involving PH3 and Ni2+.