Publication detail

Electron beam remelting of plasma sprayed alumina coatings

MATĚJÍČEK, J. VEVERKA, J. ČÍŽEK, J. KOUŘIL, J.

English title

Electron beam remelting of plasma sprayed alumina coatings

Type

conference paper

Language

en

Original abstract

Plasma sprayed alumina coatings find numerous applications in various fields, where they enhance the properties of the base material. Examples include thermal barriers, wear resistance, electrical insulation, and diffusion and corrosion barriers. A typical structure of plasma sprayed coatings, containing a multitude of voids and imperfectly bonded interfaces, gives them unique properties – particularly low thermal conductivity, high strain tolerance, etc. However, for certain applications such as permeation barriers or wear resistance, these voids may be detrimental. This paper reports on the first experiments with remelting of plasma sprayed alumina coatings by electron beam technology, with the purpose of densifying the coatings and thereby eliminating the voids. Throughout the study, several parameters of the e-beam device were varied – beam current, traverse velocity and number of passes. The treated coatings were observed by light and electron microscopy and the thickness, structure and surface morphology of the remelted layer were determined and correlated with the process parameters. Based on the first series of experiments, the e-beam settings leading to dense and smooth remelted layer of sufficient thickness were obtained. In this layer, a change of phase composition and a marked increase in hardness were observed.

English abstract

Plasma sprayed alumina coatings find numerous applications in various fields, where they enhance the properties of the base material. Examples include thermal barriers, wear resistance, electrical insulation, and diffusion and corrosion barriers. A typical structure of plasma sprayed coatings, containing a multitude of voids and imperfectly bonded interfaces, gives them unique properties – particularly low thermal conductivity, high strain tolerance, etc. However, for certain applications such as permeation barriers or wear resistance, these voids may be detrimental. This paper reports on the first experiments with remelting of plasma sprayed alumina coatings by electron beam technology, with the purpose of densifying the coatings and thereby eliminating the voids. Throughout the study, several parameters of the e-beam device were varied – beam current, traverse velocity and number of passes. The treated coatings were observed by light and electron microscopy and the thickness, structure and surface morphology of the remelted layer were determined and correlated with the process parameters. Based on the first series of experiments, the e-beam settings leading to dense and smooth remelted layer of sufficient thickness were obtained. In this layer, a change of phase composition and a marked increase in hardness were observed.

Keywords in English

plasma sprayed coating; alumina; electron beam; remelting; post-treatment

Released

01.05.2016

Publisher

Tanger Ltd.

Location

Brno

ISBN

978-80-87294-66-6

Book

METAL 2016

Pages from–to

921–927

Pages count

7

BIBTEX


@inproceedings{BUT127150,
  author="Matějíček {Jiří} and Jiří {Matějíček} and Jakub {Veverka} and Jan {Čížek} and Jan {Kouřil},
  title="Electron beam remelting of plasma sprayed alumina coatings",
  booktitle="METAL 2016",
  year="2016",
  month="May",
  pages="921--927",
  publisher="Tanger Ltd.",
  address="Brno",
  isbn="978-80-87294-66-6"
}