incorporation of zinc in electroless deposited nickel-phosphorus alloys. I. A comparative study of Ni-P and Ni-Zn-P coatings deposition, structure, and composition

• Published in: Journal of the Electrochemical Society Vol. 148; no. 4; pp. C266 - C273
• Main Authors: VALOVA, E, GEORGIEV, I, ARMYANOV, S, DELPLANCKE, J.-L, TACHEV, D, TSACHEVA, Ts, DILLE, J
• Format: Journal Article
• Language: English
• Published: Pennington, NJ Electrochemical Society 01.04.2001
• Subjects: Applied sciences; Exact sciences and technology; Metallic coatings; Metals. Metallurgy; Production techniques; Surface treatment; Scanning electron microscopy; Ternary alloy; Basic solution; X ray; Dispersive spectrometry; X ray diffraction; Phosphorus Alloys; Surface structure; Transmission electron microscopy; Energy dispersion; Morphology; Paramagnetic materials; Chemical composition; Codeposition; Nickel Alloys; Electroless plating; Zinc Alloys; Hysteresis; Binary alloy; Magnetic properties
• ISSN: 0013-4651; 1945-7111
• DOI: 10.1149/1.1354598

The impact of zinc incorporation on the chemical composition of electroless Ni-Zn-P coatings and the elements distribution through the thickness was studied. Ni-Zn-P alloy was deposited on various metal substrates (Al, Fe, Au) with and without electroless Ni-P underlayer. The employed bath formulation and the substrates with a Ni-P intermediate layer allowed direct comparison between the binary Ni-P and Ni-Zn-P alloy coatings. A reduction in phosphorus content and deposition rate due to zinc inclusion was observed. Some physical characteristics (morphology, structure, magnetic properties) of Ni-Zn-P coatings were assessed in parallel with those of Ni-P. The localization of Zn mainly at the grain boundaries together with P was proved by transmission electron microscopy combined with energy dispersive X-ray analysis system. The particular role of the steel substrate is discussed as a source of iron, subsequently included in electroless Ni-P and Ni-Zn-P coatings.