Corrosion Behavior ofWC-Co Coatings Prepared by APS Technique

Thermally sprayed We-Co cermet coatings are widely used for increasing wear resistance of industrial parts such as paper and printing cylinders, steel industry guide rolls and pins, pump casings and impelle:rs, valves, tee junctions, etc. Investigation on the corrosion and erosioncorrosion behavior of WC-CO coatings and the related mechanisms are very important for applications where both abrasive andcorrosive conditions exist. In this work the corrosion behavior of the WC-12%CO atmospheric plasma-sprayed. (APS) coatings was studied. Int1uence of the grinding operation on their corrosion resistance was also investigated. The WC-12%CO coating was applied on CK45 steel by the APS method. The grinding operation was performed by a magnetic grinding machine. The micro structural characteristics of the coatings were investigated using the scanning electron microscopy (SEM) and X-ray diffiaction (XRD). The corrosion behavior of the coatings was assessed by electrochemical tests in a 3.5% NaCl solution. Corrosion test results and chemical analysis of corrosion solutions revealed that WC-12%CO coating can effectively increase the corrosion resistance of CK45 steel and protect the substrate from the solution corrosive attack. The corrosion mechanism of the coating was determined after corrosion tests by the assessment ofthe micro stru.ctura1 characteristics ofthe coating. Furthermore, the grinding operation of the WC-12%Co coating enhanced its corrosion resistance.

کلیدواژه ها:

WC-CO Coating ، Atmospheric Plasma Spray (APS) ، Grinding ، Corrosion