Visualization of the impingement of alloy particles in high velocity thermal spraying

Bearbeiter:Dipl.-Phys. Christoph Skupsch
Beginn:September 2009
Dauer:5 Jahre
Kooperationspartner:Prof. Dr. Hans Jürgen Seifert (Karlsruhe Institute of Technology, KIT)

Inhalt:

High velocity oxy-fuel (HVOF) thermal spraying is a coating technology. Alloy particles, some 10µm in diameter, are shotonto the work piece. In the end of the bombardment, the work piece is covered with high temperature corrosion-resistant coating consisting of cramped particles. One goal of this project is the visualization of the particle impingement in HVOF thermal spraying.

Fig.1: Working principle of thermal spraying gun. In cooperation with regional partners, measurements of velocimetry fields in the HVOF jet are conducted under industrial conditions. However, to date there are no in-situ recordings of the fast impinging particles. High spatiotemporal resolution is needed for imaging the impact. Therefore, a high-speed camera is developed. It consists of a long distance microscope at 86mm working distance and high optical resolution over a field of view 1.4mm in diameter. The used high-speed camera bases on the Cranz-Schardin principle. High imaging quality is realized by laser illumination and optical switching ofFig.2 Water jet in air with bow-shock wave. The liquid propagates at more than 1km/s. The interframe time is 25ns. The field of view is about 700µm x 500µm. the cameras. The camera delivers four images with 25ns interframe time, corresponding to 40 million frames per second equivalent frame rate. Exemplarily, the camera is tested at a water jet propagating in air at more than 1 km/s.

In a next step, the camera is applied impinging alloy particles. The state of the art is published in Review of Scientific Instruments (AIP) and may be found at C. Skupsch et al., Rev. Sci. Instrum. 82, 083705 (2011) .

Copyright (2011) American Institute of Physics. This article may be downloaded for personal use only. Any other use requires prior permission of the author and the American Institute of Physics.

This work is performed within the Cluster of Excellence “Structure Design of Novel High-Performance Materials via Atomic Design and Defect Engineering (ADDE)” that is financially supported by the European Union (EU) (European regional development fund) and by the Ministry of Science and Art of Saxony (SMWK).