The effect of nano-additives containing rare earth oxides on sliding wear behavior of high chromium cast iron hardfacing alloys

High chromium cast iron (HCCI) hardfacing alloys with nano-additives were prepared. The effects of nano-additives on the microstructure of hardfacing alloys were studied by a scanning electron microscope (SEM) and an X-ray diffractometer (XRD). A Rockwell hardness tester was used to measure the hardness represented by Rockwell C-scale hardness (HRC). The friction and wear behavior of the hardfacing alloys with different nano-additives was investigated using ball-on-disc sliding wear tests. The experimental results showed that the volume fraction of primary carbide increased and then decreased with the increase of nano-additives. The volume fraction of primary carbide in the hardfacing alloy with 0.288 wt% nano-additives increased by 27% than that of the hardfacing alloy without nano-additives. The XRD results showed that hardfacing alloys were composed of M₇C₃ (M mainly represented Fe and Cr), martensite and retained austenite. The hardness of the hardfacing alloy without nano-additives was 61.5HRC. The hardness of the hardfacing alloy with 0.288 wt% nano-additives reached 64.5HRC. The wear rate of the hardfacing alloy with 0.288 wt% nano-additives decreased by 21.2% than that of the hardfacing alloy without nano-additives. The main wear mechanism of the hardfacing alloys with nano-additives was abrasion wear accompanied by severe adhesion wear.