Bending strength and wear behavior of Fe-Cr-C-B hardfacing alloys with and without rare earth oxide nanoparticles

The aim of this paper was to investigate the effect of rare earth oxide (REO) nanoparticles on the bending strength and wear behavior of Fe-Cr-C-B hardfacing alloys. Fe-based hardfacing alloys with different content of REO nanoparticles were prepared. Optical microscope and scanning electron microscope were used to observe the microstructure of the Fe-based hardfacing alloys. X-ray diffractometer was used to study the phases of the hardfacing alloys. Energy dispersive spectrometer and X-ray photoelectron spectroscopy were used to study the chemical composition. HXA-1000 Vickers micro-hardness tester and Instron universal material test machine were used to study the mechanical properties of the Fe-based hardfacing alloys. Pin-on-disk wear testing machine was used to study the wear behavior of the Fe-based hardfacing alloys. The experimental results showed that REO nanoparticles refined the primary carbide and increased the volume fraction of primary carbide. REO nanoparticles increased the fracture toughness of primary carbide. REO nanoparticles improved the bending strength of the hardfacing alloys. The bending strength of the hardfacing alloy with 0.288 wt.% REO nanoparticles increased by 46.4% compared to that of the hardfacing alloy without REO nanoparticles. The wear resistance of the hardfacing alloy was improved significantly by adding 0.288 wt.% REO nanoparticles. The main mechanisms were abrasion wear and mild oxidative wear when normal load was 5 N. When normal load was 30 N, the main mechanisms were abrasion wear and severe oxidative wear accompanied by severe adhesion.