Regeneration mechanisms of silver niobate in NiAl composites with respective addition of AgNbO3 and Ag/Nb2O5 at elevated temperatures sliding

摘要

NiAl composites with AgNbO3 (NABO1, NiAl-20 wt%AgNbO3) and Ag/Nb2O5 (NABO2, NiA1-8.68 wt%Ag-10.7 wt% Nb2O5) were fabricated by vacuum-hot-pressing sintering. Their tribological performances were evaluated in the range of 25-800 degrees C. The regeneration mechanisms of AgNbO3 for the composites with different additions methods during a high-temperature friction process were simultaneously investigated. During sintering, the decomposition of AgNbO3 to Ag/NbC phases was aggregately distributed in NABO1, while Ag/Nb2O5 phases in NABO(2) formed Ag and NbC phases that were distributed in a monomorphic state. The regeneration mechanism of AgNbO3 relies on Ag/NbC phases distribution in the composites. Particularly, during the high-temperature friction process, Ag/NbC phases in the aggregate state regenerate AgNbO3 more easily than that in the monomorphic state.