MICROSTRUCTURAL CHARACTERIZATION OF THE POWDER AND THECEMENTED CARBIDE WC-8Ni- 2Mo2C

Nádia Alves Nery Balbino¹; Edmilson Otoni Correa¹; Lívio de Carvalho Valeriano¹; Júlio Navarro Santos¹

¹ Universidade Federal de Itajubá

doi:10.20906/CPS/COB-2015-0463

Resumo

Abstract: The cemented carbides are a high performance tool material having high hot hardness at room temperature, low coefficient of thermal expansion, excellent corrosion resistance and wear resistance. Cemented carbides are conventionally obtained by compacting and liquid phase sintering process. The aim of this work was to characterize microstructurally 90%WC-8%Ni-2%Mo2C cemented carbides obtained by powder metallurgy. The powders were mixed for 80 hours and sintered at 1460ºC. The microstructural characterization of powders was done by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The sintered sample was microstructurally characterized through the analysis in optical microscopy. The density was measured by the Archimedes' method. In the Microstructural analysis, were identified the hard phase (WC) and metal binder phase (Ni). However it was not indentified molybdenum carbide, indicating a good sintering league for contents of Mo2C adopted. With optical microscopy was possible to verify the presence of porosity in the sintered samples, which implies that the samples are not fully dense. However, the relative density, 97,01%, is higher than those of the WC-10Ni cemented carbides reported in literature.

Palavras-chave: WC-8%Ni-2%Mo2C; cemented carbides; XRD; SEM