Manufacturing of high entropy alloy in the Ni-Nb-Co-Fe-Cr system by rapidly solidification method for oxide ceramic brazing

This paper presents results of research of high-entropy alloys of the Ni-Nb-Co-Fe-Cr system in the as-cast state and after rapid quenching from the melt. The results of experiments on obtaining a brazed joint of aluminum-oxide ceramics with using the filler metal of this system and the results of a studying this joint are presented. Differential thermal analysis (DTA), X-ray diffraction analysis (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray microanalysis (EDX) and measurement of microhardness were used as experimental research methods. The liquidus and solidus temperatures of high-entropy alloy Nb_0.73CoCrFeNi_2.1 were determined. The phase composition of alloys of the Ni-Nb-Co-Fe-Cr system was studied. It was shown, that alloys of this system can be used as filler metal to create a joint between ceramics. The microhardness of the brazed seam was studied. Based on these results the brazing mode for samples of aluminum-oxide ceramics with using high-entropy alloy Nb_0.73CoCrFeNi_2.1 as a filler metal was chosen.