Demands, Potentials, and Economic Aspects of Thermal Spraying with Suspensions: A Critical Review

Research output: Contribution to journalResearch articleContributedpeer-review

Contributors

  • Filofteia Laura Toma - , Fraunhofer Institute for Material and Beam Technology (Author)
  • Annegret Potthoff - , Fraunhofer Institute for Ceramic Technologies and Systems (Author)
  • Lutz Michael Berger - , Fraunhofer Institute for Ceramic Technologies and Systems (Author)
  • Christoph Leyens - , Chair of Materials Technology, Fraunhofer Institute for Material and Beam Technology, TUD Dresden University of Technology (Author)

Abstract

Research and development work for about one decade have demonstrated many unique thermal spray coating properties, particularly for oxide ceramic coatings by using suspensions of fine powders as feedstock in APS and HVOF processes. Some particular advantages are direct feeding of fine nano- and submicron-scale particles avoiding special feedstock powder preparation, ability to produce coating thicknesses ranging from 10 to 50 µm, homogeneous microstructure with less anisotropy and lower surface roughness compared to conventional coatings, possibility of retention of the initial crystalline phases, and others. This paper discusses the main aspects of thermal spraying with suspensions which have been taken into account in order to produce these coatings on an economical way. The economic efficiency of the process depends on the availability of suitable additional system components (suspension feeder, injectors), on the development and handling of stable suspensions, as well as on the high process stability for acceptance at industrial scale. Special focus is made on the development and processability of highly concentrated water-based suspensions. While costs and operational safety clearly speak for use of water as a liquid media for preparing suspensions on an industrial scale, its use is often critically discussed due to the required higher heat input during spraying compared to alcoholic suspensions.

Details

Original languageEnglish
Pages (from-to)1143-1152
Number of pages10
JournalJournal of thermal spray technology
Volume24
Issue number7
Publication statusPublished - 1 Oct 2015
Peer-reviewedYes

Keywords

Keywords

  • concentrated suspension, economic aspects, hardware development, process stability, suspension thermal spraying