Abrasion Resistance Enhancement of Ultrafine-structured WC-Co Coating Fabricated by using in situ Synthesized Composite Powder

The ultrafine WC—Co composite powder was synthesized by a newly developed rapid route based on in situ reactions.By using the as-synthesized composite powder,the granulation processing was then carried out to prepare the ultrafine-structured thermal spraying feedstock.The influences of the heat-treatment process on density of the feedstock powder,phase constitution and wear resistance of the resultant WC—Co coatings fabricated by high velocity oxy-fuel(HVOF) were investigated.The results showed that increasing the heating temperature and extending the holding time leaded to remarkable increase in the density and flowability of the feedstock powder.As a result,the decarburization of the in-flight particles could be decreased and the wear resistance of coating was significantly enhanced.The present study demonstrated that the developed techniques for the ultrafine powder and its thermal-sprayed coatings had very promising applications in scaling up to produce ultrafine-structured cermet coatings with excellent performance.