Accessible Unlicensed Requires Authentication Published by De Gruyter April 14, 2015

SNMS investigations of thermally sprayed coatings

SNMS-Untersuchungen von thermisch hergestellten Spritzschichten
Ion-Dragoş Uţu and Ion Mitelea
From the journal Materials Testing

Abstract

Surface protective coatings are commonly used in order to protect the bulk materials against corrosion and high temperature oxidation. The present publication discusses the morphology of high-velocity oxygen fuel (HVOF) sprayed MCrAlY coatings obtained from CoNiCrAlY particles (8 wt.-% Al) before and after electron beam (EB) treatment. The latter process was applied in order to achieve a homogeneous and refined structure free of pores and oxides. The microstructure and phase modification of the coatings before and after the EB remelting were characterized by scanning electron microscopy (SEM) and X-ray diffraction technique. Using the sputtered neutral mass spectrometry (SNMS) technique, the element contents (O, N, Co, Ni, Cr, Al, Y) of the coating in as sprayed and after EB irradiation were examined. Experiments have shown that while the Co concentration remains practically unchanged, significant changes in Cr, Ni, Al and Y concentrations occurred. Also, the N and O contents are lower compared to those of the as sprayed coatings.

Kurzfassung

Oberflächenschutzschichten werden häufig verwendet, um Einsatzwerkstoffe gegen Korrosion und Hochtemperaturoxidation zu schützen. In dem vorliegenden Beitrag wird die Morphologie von HVOF-Spritzschichten aus MCrAlY, die aus CoNiCrAlY-Partikeln mit 8 wt.-% Al hergestellt wurden, vor und nach einer Elektronenstrahlbehandlung untersucht. Dieser Prozess wurde angewendet, um eine homogene und verfeinerte porenfreie sowie oxidfreie Struktur zu erhalten. Hierzu wurden die Mikrostruktur und die Phasenmodifikationen der Schichten vor und nach dem Elektronenstrahlumschmelzen mittels Rasterelektronenmikroskopie und Röntgendiffratometrie untersucht. Dabei wurde die Sekundär-Neutralteilchen-Massenspektrometriee (SNMS) angewendet, um den Gehalt der Elemente O, N, Co, Ni, Cr, Al, Y in der Schicht im gespritzten Zustand und nach Elektronenstrahlbehandlung zu ermitteln. Die Experimente haben gezeigt, dass bei einer praktisch unveränderten Co-Konzentration erhebliche Änderungen in den Cr-, Ni-, Al- und Y-Konzentrationen auftraten. Auch die N- und O-Gehalte waren niedriger gegenüber dem gespritzten Ausgangszustand.


§Correspondence Address, Dr. Eng. Ion-Dragos Utu, Faculty of Mechanical Engineering, Politehnica University Timisoara, Bv. Mihai Viteazu, No.1, RO-300222, Timisoara, Romania, E-mail:

Ion-Dragos Utu, born 1978, graduated from Politehnica University of Timisoara, Romania, with a Bachelor and PhD degree and is currently a lecturer in the Department of Materials and Manufacturing Engineering in the same institution being involved in the field of materials science and surface engineering. He has pursued extensive research and teaching activities in Romania and as DAAD and SOCRATES fellow at the University of Applied Sciences Gelsenkirchen, Germany.

Ion Mitelea, born in 1946, graduated from Politehnica University of Timisoara, Romania, with a Bachelor and a PhD degree and is currently Professor of Materials Science, Materials and Heat Treatments for Welded Structures and Selection and Use of Engineering Materials in the same institution. He has pursued extensive research and teaching activities in Romania and as DAAD fellow at the Technical University Aachen, the University of Applied Sciences Gelsenkirchen and the Technical University Dortmund, Germany.


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Published Online: 2015-04-14
Published in Print: 2015-03-02

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