Microstructure characterisation and wear properties of arc sprayed NiB containing amorphous coatings.

Two kinds of cored wires were used to deposit coatings containing amorphous phase and nanocrystalline grains by arc spraying. The microstructure characteristics of the coatings were conducted by scanning electron microscopy (SEM), transmission electron microscopy (TEM), electron probe micro-analyzer (EPMA) and X-ray diffraction (XRD). The microstructures of the both coatings had lamellar morphologies. Both coatings consisted of Fe rich matrix and several kinds of borides. The Fe rich matrix had a majority amorphous phase regions with a fraction of nanocrystalline grains. The coatings' microhardness values for NiB coating is 950 HV(100 g) and for NiB–Cr3C2 coating is 1090 HV(100 g). Compared with the reference sample of Q235 steel, the coatings showed a much higher wear resistance, and the relative wear resistance of the NiB coating is 10 times while the NiB–Cr3C2 coating is 13·3 times higher than that of Q235 steel. [ABSTRACT FROM AUTHOR]