Tribological investigation of new self-fluxing nickel alloys for high temperature application: The effect of silicon distribution on glaze layer formation

The objective of this study is to investigate the tribological performance of new nickel-based self-fluxing alloys for replacing cobalt-based alloys in aircraft components. Two new NiCrSiFeB alloys, manufactured by gravity casting and laser metal deposition processes, having different microstructures, are submitted to fretting loadings and tested at temperatures ranging from ambient to 650 °C. Their wear behavior is compared to a reference Stellite 6 cobalt-based alloy. Although the two NiCrSiFeB alloys have the same chemical composition, the alloy having a coarse microstructure rich in silicates was able to form a protective glaze layer at high temperature as Stellite 6. On the other hand, the alloy having a fine microstructure underwent severe adhesive wear. This highlights the crucial effect of the microstructure and the silicon distribution in activating the formation of a protective glaze layer at high temperatures.

Acknowledgements: The authors would like to thank Olivier Graton at Laboratory of Tribology and System Dynamics (LTDS) for his help in the instrumentation part of the experiments. Besides, the authors extend their gratitude to Louis Grillot, Evan Russo, Mohammed Fartas, Tabasser Hossain, and Laulade Quesne being the interns working on this project at LTDS Laboratory. This European research project called NEMARCO (http://nemarco.eu/) received funding from the Clean Sky 2 Joint Undertaking (JU) under the grant agreement No. 101007948. The JU receives support from the European Union’s Horizon 2020 Research and Innovation Program, and the Clean Sky 2 JU members other than the European Union.