Influence of nano-WC–12Co powder addition in WC–10Co–4Cr AC-HVAF sprayed coatings on wear and erosion behaviour

Abstract

WC–10Co–4Cr coatings deposited by activated combustion-high velocity air fuel (AC-HVAF) spray process are the most commonly used system for different components prone to wear/erosion. The aim of this work is to investigate the influence of nano-WC–12Co powder addition in WC–10Co–4Cr AC-HVAF sprayed coatings on wear and erosion behaviour. Therefore, in this work, nano-WC–12Co powder was added to the sub-micron WC–10Co–4Cr powder in order to improve the hardness of WC based AC-HVAF coatings. The result shows that 15% addition of nano-WC–12Co will improve the hardness of AC-HVAF coating from 1677 to 1873 HV0.3 due to the embedding of nano-WC–12Co powder. Sliding wear test and slurry erosion test were chosen to evaluate the effect of adding nano-WC–12Co powder. The wear and erosion resistance of AC-HVAF coated samples go up with the addition of nano-WC–12Co powder, in addition, the coating hardness has also increased. The coatings have been characterised by scanning electron microscope (SEM), microhardness tester and X-ray diffractometer (XRD). The results indicated that the sample with 15% addition of nano-WC–12Co to WC–10Co–4Cr based AC-HVAF coating has the best wear and erosion resistance. In addition, this also demonstrated that it is possible to fabricate the nanostructured WC–10Co–4Cr coating with low porosity and high hardness by AC-HVAF spray deposition with reasonable thermal spraying parameters.