Preparation of Niobium-Aluminium Alloys by Aluminothermic Reduction of Nb_2O_5

摘要

Preparation of niobium-aluminium (Nb-AI) alloys was investigated by open aluminothermic reduction of Nb2O_5 using lime based slags. The influence of various process variables such as (i) the amount of Al in the charge, (ii) slag composition, (iii) use of heat energiser (KC1O_3 + Al) etc. was studied to establish conditions for good slag-metal separation and also to achieve optimum recoveries of the alloys. Alloys containing 54 to 92 percent Nb could be obtained by this route. Whereas the aluminium rich alloys (NbAl_3) were obtained at a maximum recovery of approx 98 percent, the yield of Nb - rich alloys (Nb-AI solid solution) was over 84 percent While the NbAl_3 alloys were found to contain 54.6 percent Nb, 45.2 percent Al, 0.516 percent oxygen and 0.009 percent nitrogen, the Nb-rich alloys analysed 92.3 percent Nb, 4.5 percent Al, 0.084 percent oxygen and 0.004 percent nitrogen.