Influence of thiourea on electroless Ni–P films deposited on silicon substrates

Wu, Wangping; Liu, Jianwen; Miao, Naiming; Jiang, Jin-Wu; Zhang, Yi; Zhang, Lei; Yuan, Ningyi; Wang, Qinqin; Tang, Lixin

doi:10.1007/s10854-019-01088-4

Cited by 13 publications

(1 citation statement)

References 2 publications

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“…Analysis was performed on at least five areas comprising 70% of the coating thickness, starting from the top of the coating. Despite the narrow sensitivity of the instrument, EDS was selected as a technique to determine the P quantity as reported in several works, because it is widely recognized as a technique for determining the amount of phosphorus in an electroless Ni-P system [15,22,24,27,28,30,31]. All the coated samples, unless otherwise stated, were thermally treated (right after the deposition) at 180 • C for 2 h in air to avoid hydrogen embrittlement phenomena [17,32,33]: such coatings will be referred to as as-coated hereafter.…”

Section: Solution and Coating Preparationmentioning

confidence: 99%

Medium and High Phosphorous Ni-P Coatings Obtained via an Electroless Approach: Optimization of Solution Formulation and Characterization of Coatings

Genova,

Paglia,

Pulci

et al. 2023

Coatings

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A new lead-free electroless Ni-P plating solution was developed for the deposition of coatings with medium phosphorus content (MP, 6–9 wt%), and its composition was optimized to obtain deposits with high phosphorus (HP, 10–14 wt%). Cleaning and activation treatments were studied in terms of effectiveness and influence on the deposition rate. The concentration of reagents (nickel salt, complexing agent, reducing agent and stabilizer) was studied, and their combined effect on P content and plating rate was investigated. The obtained coatings were analyzed by SEM and XRD and thermally treated at 400 °C and 600 °C to study microstructural evolution. Vickers hardness was measured on as-deposited and annealed coatings to relate hardness evolution to microstructural changes after thermal treatments. Optimal deposition conditions were determined, enabling the production of MP coatings (6.5 wt% P) with a plating rate of 40 µm/h and HP coatings (10.9 wt% P) with a plating rate of 25 µm/h at 90 °C. Samples heat-treated at 400 °C showed improved hardness thanks to crystallization and microprecipitation of Ni3P hard phases, whereas hardness decrease was observed after treatment at 600 °C due to the combined effect of grain growth and coarsening of Ni3P precipitates. No through-the-thickness cracks were detected by the Ferroxyl reagent after heat treatments.

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