Elucidation of cold-spray deposition mechanism by auger electron spectroscopic evaluation of bonding interface oxide film

Yuji Ichikawa, Ryotaro Tokoro, Masatoshi Tanno, Kazuhiro Ogawa

Research output: Contribution to journalArticle

14 Citations (Scopus)

Abstract

The relationship between the cold spray deposition mechanism, microstructure, and strength of the resulting film must be understood for this innovative process to be practical. Previous studies have suggested that the coating mechanism is reliant on breaking the natural oxide film such that metallic bonding occurs through direct contact between the metal surfaces. In this study, the proposed model was experimentally verified by a small tensile adhesion test and auger electron spectroscopy analysis of the bonding interface. Since shear deformation does not occur at the tip (south pole) of the incoming particle, the oxide film is not broken, such that the bonding strength is weak. In contrast, at the outer edge of the particle, metallic bonding occurs, attaining a level of strength that exceeds that of the base material due to the huge plastic deformation. This phenomenon is known as the “south-pole problem,” and can lead to a decrease in the overall adhesion strength despite the local adhesion being strong. However, detailed observations revealed, in parts of the deposits, particles that had adhered across their entire surface. This suggests that, provided the collision state can be controlled, it is possible to overcome the south-pole problem and improve the adhesion strength.

Original languageEnglish
Pages (from-to)39-49
Number of pages11
JournalActa Materialia
Volume164
DOIs
Publication statusPublished - 2019 Feb 1

Keywords

  • Adhesion strength
  • Auger electron spectroscopy
  • Cold spray
  • Oxide
  • South-pole problem

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Polymers and Plastics
  • Metals and Alloys

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