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@INPROCEEDINGS{Hejrani:204894,
author = {Hejrani, Elham and Sebold, Doris and Mauer, Georg and
Naumenko, Dmitry and Vassen, Robert and Quadakkers, Willem
J.},
title = {{D}ifferences in {O}xidation {R}esistance of {MC}r{A}l{Y}
{C}oatings {M}anufactured by {L}ow {P}ressure and
{H}igh-{V}elocity {A}tmospheric {P}lasma {S}praying},
reportid = {FZJ-2015-05486},
year = {2015},
note = {First prize in the poster competition},
abstract = {Gordon Conference High Temperature CorrosionNew London,
USA, 26 – 31 July 2015Differences in Oxidation Resistance
of MCrAlY Coatings Manufactured by Low Pressure and
High-Velocity Atmospheric Plasma SprayingE. Hejrani1) , D.
Sebold2), G. Mauer2), D. Naumenko1), R. Vassen2), W.J.
Quadakkers1)Forschungszentrum Jülich, Institute for Energy
and Climate Research (IEK)52425 Jülich, D1) Microstructure
and Properties of Materials (IEK-2)2) Materials Synthesis
and Processing (IEK-1)In industrial gas turbines coatings of
the MCrAlY type (M = Co, Ni) are commonly used to protect
metallic components against damage by high temperature
oxidation and corrosion processes. They are also frequently
used as bond coats in ceramic thermal barrier coating
systems. Due to the high affinity to oxygen of the alloying
additions Al, Cr and especially Y, MCrAlY coatings are often
manufactured by low pressure plasma spraying (LPPS) to
minimize oxygen uptake of the coating and prevent oxidation
of the mentioned alloying elements during processing. Plasma
spraying at atmospheric conditions (APS) is a cost-effective
alternative if it would be possible to limit the oxygen
uptake as well as to obtain sufficiently dense coatings. In
the present investigation free standing MCrAlY coatings with
a thickness of approximately 3 mm were manufactured using a
three-cathode plasma torch with a high velocity nozzle and
adapted plasma parameters. The high particle velocities
result in reduced particle oxidation during flight and
contribute to coating densification by kinetic rather than
thermal energy. Free standing coatings with the same
composition were additionally manufactured by conventional
low pressure plasma spraying (LPPS).From the free standing
coatings rectangular specimens with a thickness of 2 and 0.6
mm were machined and investigated in respect to cyclic and
isothermal oxidation testing at 1100 and 1000°C. The
isothermal tests were carried out in a thermo-gravimetrical
analysis (TGA) facility to obtain detailed information about
oxidation kinetics. The use of specimens of different
thickness allowed estimating the differences in reservoir of
free, i.e. non-oxidized Y in the coatings and its effect on
mechanisms of surface scale formation. The coating
microstructures as well as external and internal oxidation
products were characterized by using a combination of
analysis methods such as light and electron optical
microscopy, energy and wave length dispersive x-ray analysis
(EDX/WDX), x-ray diffraction (XRD), glow discharge optical
emission spectroscopy (GDOES) as well as Laser Raman
Spectroscopy (LRS). Differences in scale growth rate and
adherence as function of coating manufacturing process and
specimen thickness will be illustrated and correlated with
the results of the detailed microstructural analyses.},
month = {Jul},
date = {2015-07-26},
organization = {Gordon Research Conference High
Temperature Corrosion, New London, NH
(USA), 26 Jul 2015 - 31 Jul 2015},
subtyp = {After Call},
cin = {IEK-1 / IEK-2},
cid = {I:(DE-Juel1)IEK-1-20101013 / I:(DE-Juel1)IEK-2-20101013},
pnm = {113 - Methods and Concepts for Material Development
(POF3-113)},
pid = {G:(DE-HGF)POF3-113},
typ = {PUB:(DE-HGF)24},
url = {https://juser.fz-juelich.de/record/204894},
}