关键字：NI ALLOY; NB-TI; PERMEATION PROPERTIES; HIGH-RESISTANCE; EUTECTIC ALLOY; CO ALLOY; MEMBRANES; BEHAVIOR; PURIFICATION; DIFFUSIVITY

摘要：NbxHf(100-x)/2Co(100-x)/2 (30 <= x <= 50) alloys are a type of typical dual-phase materials with advantages of excellent hydrogen permeability, high intensity, and low cost, which are at the forefront of the development trends of new materials used for hydrogen separation. However, changes in the microstructure and hydrogen permeability after annealing of the hypereutectic alloys were unknown until now. To this end, the effect of annealing on the microstructure and hydrogen permeability of Nb35Hf32.5Co32.5 alloy is investigated in this paper. The results show that this alloy still possesses a hypereutectic structure after short-time annealing, but the above microstructural characteristics gradually disappear with an increase of annealing time (or temperature), and some new impurity phases (e.g. Co2Nb, Co2Hf and Co6Nb7) are formed. With this change, the alloys show a gradual reduction in hydrogen permeability, which is mainly attributed to the transition of the bcc-(Nb, Hf) phase in the eutectic structure, from a continuous thin layer to discontinuous granules. Furthermore, brittle fracture occurs in the alloy membranes after long-time annealing at various temperatures due to the formation of the above impurity phases. This study demonstrates that annealing cannot improve the hydrogen permeability, and on the contrary, it deteriorates the hydrogen embrittlement resistance of the Nb-Hf-Co hydrogen permeable alloys. (C) 2021 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.

卷号：46

期号：29

是否译文：否