Structural Evolution of Nb/NbC Multilayer Coatings

摘要

The present communication is concerned with the interdiffusion kinetics and the interface breakdown that take place in the Nb/NbC multilayer system as the result of thermal annealing in the 400-800℃ temperature range. Within this temperature range carbon is the diffusing species. Carbon diffuses from the carbide layer into the adjacent Nb layer, depleting its concentration within the carbide, causing the nucleation and subsequent growth of an intermediate Nb_2C layer and decreasing the width of the original Nb layer. TEM examination of the cross-sections of the multilayer specimens provides data regarding the evolution of the microstructure and, in particular, regarding the initial nucleation stage of the newly formed Nb_2C layer.