Synthesis and Characterization of a WCCoCr/NiCr Nanocomposite Obtained by High Energy Ball Milling

Reference	Presenter	Authors (Institution)	Abstract
09-065	Waleska Campos Guaglianoni	Guaglianoni, W.C.(UFRGS); Garcia, A.(Unipampa); Basegio, T.M.(UNIVERSIDADE FEDERAL DO RIO GRANDE DO SUL); BERGMANN, C.P.(UNIVERSIDADE FEDERAL DO RIO GRANDE DO SUL);	Tungsten-cobalt-chrome carbide (WCCoCr) and nickel-chrome carbide-based (NiCr) coatings are widely used in order to improve wear resistance. Many studies about coatings use conventional commercial spray powders material. The utilization of nanostructured materials may enhance the performance of these coatings. This study investigates the synthesis of a WCCoCr/NiCr nanocomposite by high energy ball milling to be applied as protective coating. WCCoCr was processed in a planetary ball mill varying the milling time (3, 6 and 12 hours). The milled material was added to a NiCr metallic matrix in the proportions of 5, 10, and 15%. The powders were characterized by X-ray diffraction (XRD), particle size analysis, surface area (BET), and scanning electron microscopy (SEM). The results showed that the WCCoCr crystallite size decreased significantly during the first milling hours and the values measured were smaller than 30 nm. The material milled for 6 hours showed the smallest crystallite size and particle mean diameter (24.5 nm and 2.94 µm, respectively), and the largest surface area (5.60 m²/g). WCCoCr-NiCr commercial samples showed larger particle mean diameter than the samples with WCCoCr nanostructured. The WCCoCr-NiCr nanocomposite with 15% of WCCoCr milled for 6 hours presented the smallest particle size distribution (20.49 µm).
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