STANCIU Victor Ioan

Spoluautoři VITRY Véronique, DELAUNOIS Fabienne

Mechanical alloying is a method that allows producing mixtures of compounds in solid state. This paper investigates the possibility to produce by mechanical alloying ready-to-use cobalt powder doped with chromium carbide to be used as binder in cemented carbides. The role of inhibitors in cemented carbides is to prevent the growth of tungsten carbide particles during the sintering process. A review of previous work leads to the conclusion that chromium carbide is a good candidate for an inhibitor: it ensures the best ratio between hardness and toughness for cemented carbides. Various amounts (1%, 5%, 10% and 20% in weight) of chromium carbide (Cr3C2) are mixed and milled together with cobalt in a Fritch planetary ball mil. They are compared to a batch of cobalt only that was milled in the same conditions, as reference. The milling conditions were as follow: vials rotation :600 rpm; Milling sequence: 5 minutes of milling followed by 5 minutes of cooling; 10 mm WC-Co milling balls; WC-Co milling bowls ; maximal milling time 10h. Samples were taken every 2 hours. They were analyzed to study the evolution of particles size and the dispersion of chromium carbide into the cobalt matrix, using the following methods: SEM, laser granulometry and X-ray diffraction. A reduction of particle size was observed for longer milling times and the best particles size distribution was obtained for the materials containing 5% wt and 10% wt of chromium carbide.

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