Improving hardness of Ni-Cr-Si-B-Fe-C thermal sprayed coatings through grain refinement by vibratory treatment during refusion

Abstract

The paper presents studies of vibratory treatment effect on the microstructure and hardness of thermally sprayed and re-fused Ni-based coatings. Ni-Cr-B-Si-Fe-C system powder has been deposited on the S235 steel substrate and re-melted with the simultaneous introduction of the horizontal mechanical vibrations of frequency from 50 Hz to 400 Hz and of amplitude from 25 μm to 185 μm. The microstructure of obtained coatings has been studied along with the microhardness. The grain refinement effect accompanied by the hardness increase up to 20 % has been obtained in vibrated coatings, and frequency from 100 Hz to 200 Hz has been established as the range of the most intensive effect. No visible influence of vibratory treatment on the phase composition has been established.