The formation of pyrochlores during plasma spraying of  REO and zirconia oxides powder mixture

Tadeusz Kubaszek; Wojciech J. Nowak; Paweł Pędrak; Kinga Trybus; Karol Ślemp; Marek Góral

doi:10.30464/jmee.2019.3.2.141

Tadeusz Kubaszek Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland https://orcid.org/0000-0002-7006-4857
Wojciech J. Nowak Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland https://orcid.org/0000-0002-5285-4900
Paweł Pędrak Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland https://orcid.org/0000-0001-5862-6792
Kinga Trybus Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland
Karol Ślemp Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland
Marek Góral Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland https://orcid.org/0000-0002-7058-510X

DOI: https://doi.org/10.30464/jmee.2019.3.2.141

Keywords: Thermal Barrier Coatings, Plasma spraying, Ceramic coating, Rare earth oxides, Pyrochlores, Porosity

Abstract

The pyrochlores are the promising low-thermal conductive materials for Thermal Barrier Coatings applications. In present work the concept of pyrochlore formation during APS spraying of ZrO₂ and ReO was analyzed. The specially prepared agglomerated mixtures of ZrO₂ with Nd₂O₃, Yb₂O₃, Er₂O₃ and Gd₂O₃ oxides were plasma sprayed using A60 plasma torch on NiCoCrAlY-type bond coat. The influence of plasma gasses composition on coatings’ microstructure was investigated. The results of XRD phase analysis proved formation of pyrochlores from Gd₂O₃ +ZrO₂ and Nd₂O₃+ZrO₂ mixtures. The formation of Er₄O₁₂Zr₃ from Er₂O₃+ ZrO₂ mixture as well as Zr₃Yb₄ from Yb₂O₃+ ZrO₂ powder was detected. The presence of pure rare earth oxides (REO) and zirconia oxides was observed in all types of sprayed coatings. The microstructural assessment showed differences in porosity and thickness of obtained ceramic coatings depending of type of REO oxides. The analysis of results showed that it is possible to obtain pyrochlore ceramic coatings from pure oxides mixture. The plasma energy was not efficient for full formation of pyrochlores, therefore the presence of pure oxides was observed.

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Author Biographies

Tadeusz Kubaszek, Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland

Tadeusz Kubaszek is a research assis-tant at Rzeszow University of Technology. He is specialized in atmospheric pressure plasma spray technologies. His scientific activity is connected with development of spraying technology, coatings microstructure and properties and process diagnostic. He published over 20 publication in Polish and international journals.

Wojciech J. Nowak, Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland

Wojciech J. Nowak is a assistant professor in Rzeszow University of Technology. He is specializes in high temperature corrosion analysis of materials and coatings especially thermal barrier coatings. Moreover, he is an expert in glow discharge optical emission spectrometry (GD-OES) analysis. He is an author of over 30 articles in international journals.

Paweł Pędrak, Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland

Pawel Pędrak is a research assistant at Rzeszow University of Technology. His research activity is connected with new ceramic materials for high temperature application. He is specialized in chemical and phase composition analysis of materials and coatings using XRF and XRD techniques. He is an author of about 10 articles in polish and international journal.

Kinga Trybus, Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland

Kinga Trybus is a MSc student of materials science at Rzeszow University of Technology. Her research activity is connected with analysis of selected REO oxides and using them as a coating.

Karol Ślemp, Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland

Karol Ślemp is a MSc student of materials science at Rzeszow University of Technology. His research activity is connected with analysis of selected REO oxides and using them as a coating.

Marek Góral, Department of Materials Science, Faculty of Mechanical Engineering and Aeronautic, Rzeszów University of Technology, Rzeszów, Poland

Marek Góral is a assistant professor at Rzeszow University of Technology. He is a specialized in high temperature protective coatings such as aluminides and thermal barrier coatings. In his area of activity is also thermal spray processes - especially low pressure plasma spraying (LPPS) and plasma spray physical vapour deposition (PS-PVD). He is an author of over 40 articles in international journals.