An inverse spinel-type metal oxide, magnesium-manganese-titanium oxide （Mg2Mn0.5Ti0.5O4）, were prepared using the coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material ...An inverse spinel-type metal oxide, magnesium-manganese-titanium oxide （Mg2Mn0.5Ti0.5O4）, were prepared using the coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material was investigated by X-ray, saturation capacity of exchange, pH titration, and distribution coefficient （Kd） measurement. The acid treatments of Mg2Mn0.5Ti0.5O4 caused Mg^2＋ extractions of more than 81%, whereas the dissolutions of Mn^4＋ and Ti^4＋ were less than 10%. The experimental results proved that the acid-treated sample has a capacity of exchange 56 mg·g^-1 for Li^＋ in the solution. The chemical analysis showed that the Li^＋ extraction/insertion progressed mainly by ion-exchange mechanism and surface adsorption.展开更多
Hot corrosion is a serious problem in aircraft, marine, industrial and land-base gas turbines. To obviate these problems, superalloy superfer 800H (Midhani grade) is one of the prominent materials for the high tempera...Hot corrosion is a serious problem in aircraft, marine, industrial and land-base gas turbines. To obviate these problems, superalloy superfer 800H (Midhani grade) is one of the prominent materials for the high temperature applications. The present work investigates hot corrosion behaviour of superfer 800H exposed to two different molten salt environments Na2SO4 + 60% V2O5 and Na2SO4 + 5% V2O5 + 5% NaCl respectively, at 900oC under cyclic conditions. The weight change measurements made on during the experiments are used to determine the kinetics of hot corrosion. It is observed that the formation of scale rich in Cr2O3, NiO and spinel NiCr2O4 has contributed for the better hot corrosion resistance of superfer 800H. Inspection for 10, 20, 35 and 50 cycles reveals that after 10 cycles Crack has been initiated in the scale and it is clearly visible in the presence of NaCl salt. On subsequent cycles, crack propagates perpendicular to surface and as it encounters inclusions.展开更多
文摘An inverse spinel-type metal oxide, magnesium-manganese-titanium oxide （Mg2Mn0.5Ti0.5O4）, were prepared using the coprecipitation/thermal crystallization method. The extraction/insertion reaction with this material was investigated by X-ray, saturation capacity of exchange, pH titration, and distribution coefficient （Kd） measurement. The acid treatments of Mg2Mn0.5Ti0.5O4 caused Mg^2＋ extractions of more than 81%, whereas the dissolutions of Mn^4＋ and Ti^4＋ were less than 10%. The experimental results proved that the acid-treated sample has a capacity of exchange 56 mg·g^-1 for Li^＋ in the solution. The chemical analysis showed that the Li^＋ extraction/insertion progressed mainly by ion-exchange mechanism and surface adsorption.
文摘Hot corrosion is a serious problem in aircraft, marine, industrial and land-base gas turbines. To obviate these problems, superalloy superfer 800H (Midhani grade) is one of the prominent materials for the high temperature applications. The present work investigates hot corrosion behaviour of superfer 800H exposed to two different molten salt environments Na2SO4 + 60% V2O5 and Na2SO4 + 5% V2O5 + 5% NaCl respectively, at 900oC under cyclic conditions. The weight change measurements made on during the experiments are used to determine the kinetics of hot corrosion. It is observed that the formation of scale rich in Cr2O3, NiO and spinel NiCr2O4 has contributed for the better hot corrosion resistance of superfer 800H. Inspection for 10, 20, 35 and 50 cycles reveals that after 10 cycles Crack has been initiated in the scale and it is clearly visible in the presence of NaCl salt. On subsequent cycles, crack propagates perpendicular to surface and as it encounters inclusions.
