Sinterização de ligas de Ti-Nb protegida por sal fundido ; Sinterization of Ti-Nb alloys protected by melted salt

The present work aims on evaluating sintering of titanium and niobium alloys, a molten salt (potassium chloride) shield. In this context, two samples were produced containing 10 wt% of niobium (Ti10Nb); and two samples containing 22 wt% of niobium (Ti22Nb). Then, they were encapsulated in potassium chloride, placed in closed crucible and sintered in a resistive furnace. Sintering was performed at 1000 ºC with a dwell time of 3 hours. The sample cooling took place slowly inside the furnace. After this process, the samples were immersed in water bath at 90 ºC, for 168 hours, in order to remove the residual salt. Finally, the specimens were metallo-graphic prepared for microstructural characterization. The results reported that samples with lower amount of niobium have greater hardness when compared to samples containing higher amount. The XRD results revealed that alpha and beta phases coexist in both samples, however, Ti10Nb composition has higher amount of α phase. By analyzing the micrographs, it was pos-sible to confirm the results obtained by XRD. In addition, the samples of both the compositions exhibited two types of pores: micro and macropores. The micropores are typically a residual porosity of the sintering process, whereas the macropores may be related to the low load applied during powder compaction and to low sintering temperature. To quantify the porosity of the samples, image analysis and Archimedes method were used. The values of porosity were sim-ilar to values of fifty-three percent which reported in the literature, which suggested the achieved porosity is suitable to produce prostheses and biocompatible implants. Finally, Energy Dispersive X-ray spectroscopy (EDS) analysis indicated that the contamination by atmospheric gases and residual salt is minimal and sintering occurred as expected. ; O presente trabalho tem por objetivo avaliar a sinterização de amostras de ligas de titânio e nióbio, utilizando uma atmosfera protetora de sal fundido (cloreto de potássio). Nesse sentido, foram produzidas ...