Authors: Tillmann, Wolfgang
Abdulgader, Mohamed
Wirtz, Andreas
Milz, Michael P.
Biermann, Dirk
Walther, Frank
Title: The effect of argon as atomization gas on the microstructure, machine hammer peening post-treatment, and corrosion behavior of twin wire arc sprayed (TWAS) ZnAl4 coatings
Language (ISO): en
Abstract: In the twin wire arc spraying (TWAS) process, it is common to use compressed air as atomizing gas. Nitrogen or argon also are used to reduce oxidation and improve coating performance. The heat required to melt the feedstock material depends on the electrical conductivity of the wires used and the ionization energy of both the feedstock material and atomization gas. In the case of ZnAl4, no phase changes were recorded in the obtained coatings by using either compressed air or argon as atomization gas. This fact has led to the assumption that the melting behavior of ZnAl4 with its low melting and evaporating temperature is different from materials with a higher melting point, such as Fe and Ni, which also explains the unexpected compressive residual stresses in the as-sprayed conditions. The heavier atomization gas, argon, led to slightly higher compressive stresses and oxide content. Compressed air as atomization gas led to lower porosity, decreased surface roughness, and better corrosion resistance. In the case of argon, Al precipitated in the form of small particles. The post-treatment machine hammer peening (MHP) has induced horizontal cracks in compressed air sprayed coatings. These cracks were mainly initiated in the oxidized Al phase.
Subject Headings: Twin wire arc spraying process
Atomization gas
ZnAl4 coatings
Machine hammer peening
Corrosion behavior
Subject Headings (RSWK): Thermisches Spritzen
Maschinelles Oberflächenhämmern
Issue Date: 2021-12-27
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Appears in Collections:Lehrstuhl für Werkstofftechnologie

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