Densification and mechanical properties of liquid phase sintered tantalum

Abstract

This paper has as main objective to investigate the influence of nickel (Ni), iron (Fe) and copper (Cu) addition on the tantalum (Ta) powder processing, by promoting a liquid phase sintering (LPS). The role of these metals is to lower the Ta sintering temperature, maintaining good densification and mechanical properties.Ni, Fe and Cu 1wt% additions to Ta powder were performed. Samples were cold pressed at 350 MPa. Sintering was carried out at 1300 to 2000 C, for 1 hour, under a vacuum of 10 -6 Pa. Density, linear shrinkage and activation energy were measured and calculated. Hardness and compression tests were also conducted. Ni was the most promissing Ta LPS activator, once it enabled the best results of densification and mechanical properties.

Archives of Metallurgy and Materials

“…The difference of pore shapes in these two materials is attributed to the distinct sintering mechanisms. The CrL-0.5C induces only solid phase sintering, and the pores are formed at the corners of tetrakaidecahedron particles resulting in the formation of spheroid-shaped pores [20]. On the other hand, the CrL-0.5C-1Cu undergoes liquid phase sintering because of the presence of Cu, and the liquid phase Cu flows along particle boundaries.…”