Effect of CeO 2 addition on the microstructure,hardness,and abrasive wear behaviour of flame-sprayed Ni-based coatings

Abstract

This article describes the effect of addition of CeO₂ on the microstructure, hardness, and abrasive wear behaviour of Ni-based flame-sprayed coatings. These coatings are economical but not frequently used because of their high porosity, low hardness, and bigger grain size. The mechanical and tribological properties of the coatings are governed by the microstructure, grain size, and distribution of various elements. Rare earth elements (oxides) refine the microstructure. The commercially available Ni-based powder was modified with the addition of CeO₂ (0.4, 0.8, 1.2, 1.6, and 2 %wt). The conventional Ni-based coatings and those containing various amounts of CeO₂ were compared in terms of grain size and distribution of various elements, hardness, porosity, and abrasive wear behaviour. The addition of an optimal amount of CeO₂ (0.8 %wt) refines the grain size and improves hardness and abrasive wear resistance of the coatings. X-ray diffraction of the conventional and modified coating with an optimum addition of CeO₂ (0.8 %wt) was also carried out to identify the various phases present in the coating.