EFFECT OF CEO2 AND LA2O3 REINFORCEMENTS ON MECHANICAL, TRIBOLOGICAL AND MICROSTRUCTURAL PROPERTIES OF WC–12CO COATING BY HIGH-VELOCITY OXYGEN FUEL DEPOSITION TECHNIQUE

Decarburization during HVOF deposition reduces the workability of Tungsten Carbide-12% Cobalt (WC-12Co) coatings. This work examines how CeO2 and La2O3 reinforcements affect HVOF-sprayed WC-12Co coatings' mechanical, tribological, and microstructural characteristics. Compared to the unreinforced coating, microstructure, phase composition, bond strength, abrasive wear, coefficient of friction, and microhardness were assessed. CeO2 or La2O3 decreased porosity and finer grain structure without affecting bond strength. Coatings with 1 wt.% CeO2 and La2O3 increased microhardness by 6% and 4%, respectively, compared to the unreinforced WC-12Co coating, which had an adhesive bond strength of 73.60 ± 5 MPa. Both changed coatings improved structural stability, grain refinement, and densification. Minimum wear rate of 3.5 × 10⁻⁵ mm³/N·m was found in WC-12Co-1La2O3, whereas the lowest coefficient of friction was 0.4 in WC-12Co-1CeO2. An oxide layer from reinforcements enhanced wear resistance. SEM investigation of worn surfaces showed debris, dislodged carbide particles, SiC grains, microcracks, and grooves as the predominant wear processes.