Abrasive Wear Mechanism in Near-Nano and Microstructured WC-Cobalt Coatings
Abrasive wear mechanism in HVOF sprayed near-nano and microstructured WC-17wt.%Co coatings was studied. The crack propagation mechanism shows that it propagates only through cobalt matrix in the case of near-nanostructured coatings while both trans-granular and intergranular crack propagation was observed in the microstructured coatings. SEM images show a relatively ductile failure mechanism in the near-nanostructured coating, while a brittle failure mechanism dominated in the microstructured coating. AFM images show that the worn surface is smooth in near-nanostructured coatings with an average roughness value of 19 nm, while the roughness on the microstructured coating worn surface was recorded at 83 nm. Further, the wear debris formed on the near-nanostructured coated surface was mostly spherical and finer, whereas this was irregular and coarser in the microstructured counterpart. The wear behaviour suggested a lower wear rate in the near-nanostructured coatings than the microstructured coating. This was further confirmed by abrasive wear tests results.
A. Mateen and T.I. Khan, "Abrasive Wear Mechanism in Near-Nano and Microstructured WC-Cobalt Coatings", Applied Mechanics and Materials, Vols. 229-231, pp. 678-683, 2012