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| Abstract No.: |
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| Title: |
Influence of coating properties and a mechanical post-treatment step on the corrosion resistance of sealed thermal sprayed coatings
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| Authors: |
Thomas Lindner / Chemnitz University of Technology, Germany
Martin Löbel / Institute of Materials Science and Engineering, Chemnitz University of Technology, Germany
Thomas Lampke/ Institute of Materials Science and Engineering, Chemnitz University of Technology, Germany
Christian Pluta/ JELN Imprägnierung GmbH, Germany
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| Abstract: |
Thermal spayed coatings are usually exposed to corrosive environments. Depending on the special characteristics of the coating process, the deposited coatings often exhibit a certain degree of porosity. If the pores form an interconnected network, corrosive media can penetrate the coating and attack the substrate. In order to avoid this, a suitable post-treatment step is necessary. Due to its flexible application, the sealing process is the most common method in industrial practice. In this study, the corrosion protection of different sealer types was investigated in dependence of coating thickness, porosity level and mechanical post-treatment step. The sealers were characterized by the measurement of viscosity, shrinkage and temperature stability. Arc-sprayed NiAl955 and HVOF-sprayed WC/Co-Cr 84-10-6 coatings were sealed with one- and two-component polymer sealer types. The penetration depth of the sealers was determined by ultraviolet imaging of the coating cross-sections. The results of the corrosion tests indicate that a thin coating with a high porosity, which is mechanically post-treated after sealing, shows the highest tendency to corrosion. The novel sealers lead to a significant reduction or complete elimination of corrosive attack in a salt spray test over 28 days exposure.
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