Synthesising Carbo-Nitrides of some D-Group Transition Metals Using a Solar Furnace at PSA

Abstract

Carbo-nitride synthesis was undertaken using a solar furnace at PSA in flowing N2/Ar gas mixture under total pressure 1 atm and processing temperatureT= 1600°C for some d-group transition elements (Ti; Zr, V, Nb, Mo, W) starting from 1.5G/M (graphite/metal powder mixture with mole ratio 1.5:1) compact to ensure co-presence of free carbon with the reaction product. Clear X-ray diffraction (XRD) evidence of formation of carbo-nitride was detected for Ti (IVa group metal) showing higher N content in the carbo-nitride synthesised in N2gas environment at partial pressurep(N2) = 1 atm than that atp(N2) = 0.5 atm. For M = V and Nb (Va group metals), formation of mono-carbide MC single-phase was detected in the N2environment showing no evidence of formation of carbo-nitride in spite of presence of N2in the environment. For M = Mo and W (VIa group metals), formation of higher carbide, among several options of carbide phases, appeared to be promoted in the N2gas environment although, like in cases with the Va group metals, no evidence of dissolution of N into the reaction product was detected. As such, atT= 1600°C in N2gas environment up top(N2) = 1 atm under concentrated solar beam, carbo-nitride formed from the 1.5G/M mixture only for IVa group metal (Ti) but not for Va and VIa group metals. Anyway, it seemed certain that N2gas affected somehow the reaction path between G and M to yield the carbide phase for M = V, Nb, Mo and W.

Synthesizing higher nitride of molybdenum (Mo) and iron (Fe) in ammonia (NH3) gas stream under irradiation of concentrated solar beam in a solar furnace

“…The optical configuration in the solar furnace solar furnace at Plataforma Solar de Almería was basically identical to the one we have been using since 1997 and thence the details might be referred to elsewhere [15][16][17][18][19][20][21][22][23][24][25]. The current solar furnace solar furnace system at Plataforma Solar de Almería was with much improved monitoring systems as well as with upgraded quality of optical components (reflectors and concentrator).…”

Nitriding VI-group metals (Cr, Mo and W) in stream of NH3 gas under concentrated solar irradiation in a solar furnace at PSA (Plataforma Solar de Almería)

“…Noting difficulty of synthesizing nitride of VIa-group metals (Hägg, 1930;Mills, 1970Mills, , 1972Toth, 1971;Fromm and Gebhardt, 1976;Yoshizawa et al, 1977;Jehn and Ettmayer, 1978;Pierson, 1996;Ren et al, 1999;Inumaru et al, 2008;Shohoji et al, 2011Shohoji et al, , 2013aShohoji et al, , 2013b in conventional electric furnace even in uncracked NH 3 gas, the demonstrated option in the present work to undertake nitriding in NH 3 gas stream under concentrated solar irradiation seem to be of pragmatic convenience to synthesize precursor nitride powders to be subjected to further subsequent nitriding process.…”