Effect of La₂O₃ Addition on Microstructure and Wear Resistance Properties of Laser Cladded Iron-Based Alloy Coating

The iron-based alloy cladding layers with mass fractions of 0, 0.7%, 1.4% and 2.0% of La₂O₃ were prepared on the surface of 35CrMoV steel by laser cladding. The effect of La₂O₃ concent on the microstructure, phase composition, microhardness, friction and wear resistance and impact abrasive wear resistance of the cladding layer was studied. The results show that the cladding layer without La₂O₃ was mainly composed of FeCr solid solution and Cr₂₃C₆, and LaNi₃ appeared in the cladding layer after adding La₂O₃. When the mass fraction of La₂O₃ was 1.4%, the interface between cladding layer and matrix was smooth, the metallurgical bond was good, and the microstructure was fine and uniform. With the increase of La₂O₃ mass fraction, the microhardness, friction and wear resistance and impact abrasive wear resistance of the cladding layer first increased and then decreased. When the mass fraction of La₂O₃ was 1.4%, the wear resistance was the best. At this time, compared to the cladding layer without La₂O₃, the friction and wear mechanism of the cladding layer changed from severe adhesive wear to mild ploughing wear. And the furrows and irregularity on impact abrasive wear surface disappeared, and the surface tended to be flat.