Analytical methods to characterize heterogeneous raw material for thermal spray process: cored wire Inconel 625

T Lindner,T Lampke,L Pawlowski,T Grund,R Drehmann,S Bonebeau

doi:10.1088/1757-899x/118/1/012009

Abstract

In wire arc spraying, the raw material needs to exhibit sufficient formability and ductility in order to be processed. By using an electrically conductive, metallic sheath, it is also possible to handle non-conductive and/or brittle materials such as ceramics. In comparison to massive wire, a cored wire has a heterogeneous material distribution. Due to this fact and the complex thermodynamic processes during wire arc spraying, it is very difficult to predict the resulting chemical composition in the coating with sufficient accuracy. An Inconel 625 cored wire was used to investigate this issue. In a comparative study, the analytical results of the raw material were compared to arc sprayed coatings and droplets, which were remelted in an arc furnace under argon atmosphere. Energy-dispersive X-ray spectroscopy (EDX) and X-ray fluorescence (XRF) analysis were used to determine the chemical composition. The phase determination was performed by X-ray diffraction (XRD). The results were related to the manufacturer specifications and evaluated in respect to differences in the chemical composition. The comparison between the feedstock powder, the remelted droplets and the thermally sprayed coatings allows to evaluate the influence of the processing methods on the resulting chemical and phase composition.

Highlights

In thermal spraying wire-shaped feedstock material is mainly used for arc spray techniques
Coating As stated previously, this study focuses on the Ni-base material Inconel 625 (IN625)
This suggests that alloy systems for arc spraying in form of cored wire, which include certain amounts of refractory elements and elements that tend to vanish during the spraying process, need to be composed in consideration of the change in chemical composition by processing

Summary

Introduction

In thermal spraying wire-shaped feedstock material is mainly used for arc spray techniques It is available as massive material or as hollow sheath with pre-processed powder inside. For small quantities, cored wires are usually cheaper than massive wires or even the only wire form, which is commercially available. This can be attributed to the fact that most wire manufacturers have a wide selection of powders and thin metal sheets in stock, which allows the on-demand production of cored wires in the customer-requested quantity. Cored wires offer the opportunity to adjust almost any desired material mixture by filling the appropriate powder in the hollow sheath This allows the production of coatings, that cannot be achieved by other coating processes.

Experimental

Results and discussion

Conclusion