Effect of La2O3 addition on the microstructure, hardness and abrasive wear behavior of flame sprayed Ni based coatings

This paper describes the effect of rare earth elements (La2O3) on the microstructure; hardness and abrasive wear behavior of Ni based flame sprayed coatings. The mechanical and tribological properties of the coatings can be significantly improved by refinement of grain structure of the coatings. A commercially available Ni based powder was modified with the addition of La2O3 (0.4–2 wt.%) to refine the grain structure of coatings. Unmodified and La-modified coatings were investigated in respect of microstructure, hardness and abrasive wear behavior. It has been observed that an optimal addition of La2O3 (1.2 wt.%) refines the grain size, improves hardness and abrasive wear resistance of the coatings. The XRD of the unmodified and La-modified coating with optimum addition of La2O3 (1.2 wt.%) was also carried out to identify the various phases present in the coating.