US EPA

8272821 

Journal Article 

Microstructure, mechanical properties and oxidation resistance of the Nb-Si-B type powder compacts prepared by spark plasma sintering 

Murakami, T; Kitahara, A; Yamaguchi, M 

2000 

54 

3 

105-109 

Japanese 

Spark plasma sintered compacts with eight different compositions of the Nb-Si-B system were prepared via the following three routes: (i) elemental powders were mixed in a hexane-filled ball mill and then sintered by spark plasma sintering method, (ii) elemental powders were mechanically alloyed and sintered similarly to (i), and (iii) blended elemental powders were pre-sintered, milled and sintered once again similarly to (i). Microstructure, mechanical properties and oxidation behaviors of each compact were investigated. Inhomogeneous microstructure was observed in the compacts prepared via the first route, while a large amount of oxide phases was observed in the compacts prepared via the second route. However, both homogeneous microstructure and a small amount of oxide phases were seen in the compacts prepared via the third route. The compacts with compositions around the line of Nb5Si3-Nb5Si3B2-NbB 2 showed a high hardness at room temperature and a high comprcssive strength at high temperatures in comparison to those with compositions away from the line. The oxidation resistance of Nb5Si3B2 compact was superior to that of Nb5Si3 compact, but extremely worse than that of NbSi2 compact. 

Niobium alloys; Oxidation resistance; Spark plasma sintering