Abstract:
The Ag
2Nb
4O
11 powders with micro grade particle were synthesized by high-temperature solid state reaction method, then NiAl-based composites with the addition of Ag
2Nb
4O
11 (NABO20, NiAl-20%Ag
2Nb
4O
11) were prepared by powder metallurgy technology. The influence of silver niobates (Ag
2Nb
4O
11) on the microstructure, mechanical properties and tribological behaviors of NiAl-based composites at elevated temperatures was investigated. The results showed that the Ag
2Nb
4O
11 phase was decomposed and reacted with C element to form NbC and Ag phase in hot-pressing sintering process. The addition of Ag
2Nb
4O
11 slightly increased the density of composite and significantly increased the microhardness of composites. At 800 ℃, because the complete and smooth lubrication films (Nb
2O
5, Al
2O
3, Ag
2Nb
4O
11, AgNbO
3 and AgNb
3O
8) on worn surfaces of NABO20 composite and Al
2O
3 counterpart ball prevented the direct contact of the composite and its counterpart, the wear-resistance of the composite was improved effectively.