| Abstrakt: |
Features of the structure of coatings made by high-speed plasma-arc spraying of wire with a steel sheath and B4C powder filler with addition of nanosized ZrO2 powder were studied. Coatings with low porosity (about 1 %), lamellar structure and high hardness were produced on a low-carbon steel substrate. Processes of interaction, running in plasma- arc spraying between the sheath, making up 90 wt.% of the wire, and the filler, were analyzed. Ferrite matrix of the coating is alloyed with boron and carbon, and contains an amorphous phase. It is strengthened by dispersed carbide, borocarbide and oxide particles. Addition of 0.5 % of ZrO2 nanopowder promotes refinement of the coating structure with formation of dispersed borocarbides Fe3(B, C), Fe(B, C)2, and oxides of iron FeO and boron B3O5. Coating microhardness reaches 6.86 GPa that is 4 times greater than that of the ferrite sheath. Coatings of this class can be applied as wear-resistant ones for protection of equipment from gas-abrasive wear in chemical engineering, in manufacturing parts of pumps, compressors and other items, as well as reconditioning worn parts. [ABSTRACT FROM AUTHOR] |
