Enhancement of oxidation and wear resistance of Fe-based amorphous coatings by surface modification of feedstock powders

• Ni–W–P amorphous layer is coated on Fe-based amorphous powders by electroless plating.
• Coating by the modified powders has less oxygen content at intersplat regions.
• The modified coating shows improved oxidation resistance than unmodified coating.
• It exhibits superior friction/wear resistance over unmodified coating.

Surface oxidation of the in-flight powders during the preparation of amorphous coatings in high velocity oxygen fuel process causes the formation of oxygen-rich intersplat regions. These regions are brittle in nature and can dramatically deteriorate the mechanical performance of the coatings. To solve this problem, the starting FeCrMoCBY amorphous feedstock powders were modified by electroless plating a thin layer of Ni–W–P amorphous phase. It was found that the covering of the Ni–W–P layer can significantly reduce the oxygen content in the resultant Fe-based amorphous coatings. The wear resistance of the coatings with and without the modification of Ni–W–P thin layer was comparatively studied by ball-on-disk wear tests against Si3N4 counterpart in air. It revealed that the wear of two types of coatings follows the same oxidation wear mechanism but the modified coating exhibits much better wear resistance due to the improved oxidation resistance.

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