ELECTRON BEAM REMELTING OF PLASMA SPRAYED ALUMINA COATINGS

0467885 - ÚFP 2017 RIV CZ eng C - Conference Paper (international conference)
Matějíček, Jiří - Veverka, J. - Čížek, J. - Kouřil, J.
ELECTRON BEAM REMELTING OF PLASMA SPRAYED ALUMINA COATINGS.
METAL 2016 – Conference proceedings: 25th Anniversary International Conference on Metallurgy and Materials. Ostrava: TANGER Ltd., Ostrava, 2016, s. 921-927. METAL. ISBN 978-80-87294-67-3.
[METAL 2016 - 25th Anniversary International Conference on Metallurgy and Materials/25./. Brno (CZ), 25.05.2016-27.05.2016]
R&D Projects: GA ČR(CZ) GA14-12837S
Institutional support: RVO:61389021
Keywords : Plasma sprayed coating * alumina * electron beam * remelting * post-treatment
Subject RIV: JK - Corrosion ; Surface Treatment of Materials

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.

Permanent Link: http://hdl.handle.net/11104/0265874