Consolidation of binderless NbC by spark plasma sintering

Reference	Presenter	Authors (Institution)	Abstract
09-080	Sydney Ferreira Santos	de Siqueira, L.E.(Universidade Federal do ABC); Cuppari, M.G.(Universidade Federal do ABC); Trombini, V.(Universidade Federal do ABC); Machado, I.F.(Universidade de São Paulo); Santos, S.F.(Universidade Federal do ABC);	NbC is a compound with unique combination of interesting properties highlighting its high hardness, good wear resistance, good electrical conductivity, stability in several chemical aggressive environments, and so on. These features make this compound a potential candidate for technological applications such as hard electrical contacts, contact coatings for microelectronics and machining and forming tools. Developments on the processing routes for NbC parts are very important to allow its practical use. Therefore, we performed an investigation on the consolidation of binderless NbC by spark plasma sintering. The sintering temperatures investigated were 1400, 1550, and 1700 ºC and the isothermal times of 0, 1, 5, and 15 min. Sintered bodies had their apparent densities measured and were characterized by optical microscopy, confocal scanning laser microscopy, scanning electron microscopy, and X-ray diffractometry. Mechanical properties were measured by micro and nanohardness tests. Densification increased more markedly with the temperature increase. Sample sintered by 15 min at 1700 ºC reached 96.2 % of apparent density. For lower temperatures and short times of sintering, it was still possible to observe some individual particles with sintering necks. Pores quantification and morphology were examined by microscopy techniques. Increase in time and temperature of sintering resulted in porosity reduction. XRD patterns indicated that different preferential orientations were developed for the sintered samples, depending on the SPS parameters adopted.
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