Electrochemical processing and thermal properties of functional core/multi-shell ZnAl/Ni/NiP microparticles

David Svetlizky, Honorata Kazimierczak, Bar Ovadia, Ariel Sharoni, Noam Eliaz

Research output: Contribution to journalArticlepeer-review

Abstract

Electroless deposition on zinc and its alloys is challenging because of the negative standard potential of zinc, the formation of poor surface layers during oxidation in aqueous solutions, and extensive hydrogen evolution. Therefore, there are only few reports of electroless deposition on Zn and its alloys, neither of them on micro/nano powders. Here, we propose a two-step process that allows the formation of compact, uniform, and conformal Ni/NiP shell on Zn-based alloy micropar-ticles without agglomeration. The process utilizes controlled galvanic displacement of Ni deposition in ethanol-based bath, followed by NiP autocatalytic deposition in an alkaline aqueous solution. The mechanism and effect of deposition conditions on the shell formation are discussed. Thermal stability and functional analysis of core-shell powder reveal a thermal storage capability of 98.5% with an encapsulation ratio of 66.5%. No significant morphological change of the core-shell powder and no apparent leakage of the ZnAl alloy through the Ni shell are evident following differential scanning calorimetry tests. Our two-step process paves the way to utilize electroless deposition for depositing metallic-based functional coatings on Zn-based bulk and powder materials.

Original languageEnglish
Article number834
Pages (from-to)1-22
Number of pages22
JournalMaterials
Volume14
Issue number4
DOIs
StatePublished - 2 Feb 2021

Keywords

  • Additive manufacturing
  • Autocatalytic deposition
  • Coating
  • Core-shell powder
  • Electroless deposition
  • Galvanic displacement
  • Phase change materials (PCMs)
  • Thermal stability
  • Zinc al-loy

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