GALLIUM SUBOXIDE VAPOR ATTACK OF CHROMIUM, COBALT, MOLYBDENUM, TUNGSTEN AND THEIR ALLOYS AT 1200°C

摘要

Our prior work elucidated the failure mechanism of furnace materials (304 SS, 316 SS, and Hastelloy C-276) exposed to gallium suboxide (Ga2O) and / or gallium oxide (Ga2O3) during plutonium -gallium compound processing. Failure was hypothesized to result from concurrent alloy oxidation / Ga compound reduction followed by Ga uptake. The aim of the current work is to screen candidate replacement materials. Alloys Haynes 25 (49 Co - 20 Cr - 15 W - 10 Ni - 3 Fe - 2 Mn -0.4 Si, wt%), 52 Mo - 48 Re (wt%), 62 W - 38 Cu (wt%), and commercially pure Cr, Co, Mo, W, and alumina were examined. Preliminary assessments of commercially pure W and Mo -Re suggest that these materials may be suitable for furnace construction. Thermodynamics calculations indicating that materials containing Al, Cr, Mn, Si, and V would be susceptible to oxidation in the presence of Ga2O were validated by experimental results. In contrast to that reported previously, an alternate reaction mechanism for Ga uptake, which does not require concurrent alloy oxidation, controls Ga uptake for certain materials. A correlation between Ga solubility and uptake was noted.