Thermodynamics for chemical vapor synthesis(CVS)of Nb nanopowder in NbCl5-H2-Ar system was investigated by using FactSage software.The validation experiments were conducted to confirm the thermodynamics points.The res...Thermodynamics for chemical vapor synthesis(CVS)of Nb nanopowder in NbCl5-H2-Ar system was investigated by using FactSage software.The validation experiments were conducted to confirm the thermodynamics points.The results indicate that under the atmospheric pressure,the reduction approach from NbCl5(g)to Nb(s)is a stage-wise process with the formation of complex sub-chlorides,and is controllable at low hydrogen ratio(mole ratio of n(NbCl5):n(H2)【1:180)and low temperature(【1050°C).Furthermore,a reasonable amount of inert loading gas is favorable to increase the reduction ratio of NbCl5 and the powder yield.The as-synthesized Nb nanopowder with the homogeneous size of 30-50 nm and the powder yield of 85%(mass fraction)is obtained by the CVS process under n(NbCl5):n(H2):n(Ar)=1:120:1 and 950°C with the NbCl5 reduction rate of 96.1%.展开更多
基金Project(51102015)supported by the National Natural Science Foundation of China
文摘Thermodynamics for chemical vapor synthesis(CVS)of Nb nanopowder in NbCl5-H2-Ar system was investigated by using FactSage software.The validation experiments were conducted to confirm the thermodynamics points.The results indicate that under the atmospheric pressure,the reduction approach from NbCl5(g)to Nb(s)is a stage-wise process with the formation of complex sub-chlorides,and is controllable at low hydrogen ratio(mole ratio of n(NbCl5):n(H2)【1:180)and low temperature(【1050°C).Furthermore,a reasonable amount of inert loading gas is favorable to increase the reduction ratio of NbCl5 and the powder yield.The as-synthesized Nb nanopowder with the homogeneous size of 30-50 nm and the powder yield of 85%(mass fraction)is obtained by the CVS process under n(NbCl5):n(H2):n(Ar)=1:120:1 and 950°C with the NbCl5 reduction rate of 96.1%.
