The diffusible hydrogen contents in precharged (Co,Fe) 3V alloy were measured. It is found that atomic ordering can not promote hydrogen penetration in the (Co,Fe) 3V alloy. The ultimate tensile strength (UTS) and duc...The diffusible hydrogen contents in precharged (Co,Fe) 3V alloy were measured. It is found that atomic ordering can not promote hydrogen penetration in the (Co,Fe) 3V alloy. The ultimate tensile strength (UTS) and ductilities in various condition were also investigated. The results show that the UTS and elongation of disordered alloy are higher than that of ordered one with fixed diffusible hydrogen content and (Co,Fe) 3V alloy with ordered structure is highly susceptible to the embrittlement in hydrogen gas. The factor which may affect the susceptibility to the embrittlement of (Co,Fe) 3V alloy in hydrogen gas is mainly due to that the atomic ordering may accelerate the kinetics of the catalytic reaction for the dissociation of molecular hydrogen into atomic hydrogen. However, it can not be roled out that atomic ordering intensifies planar slip and restricts cross slip at the grain boundaries and enhances the susceptibility of the alloy to hydrogen embrittlement.展开更多
As a potential ferromagnetic shape memory alloy, Ni-Co-Al has excellent mechanical properties, large ma gentic-field-induced strain and high martensitic transformation temperature. The relationship between microstruct...As a potential ferromagnetic shape memory alloy, Ni-Co-Al has excellent mechanical properties, large ma gentic-field-induced strain and high martensitic transformation temperature. The relationship between microstructure and performance （mechanical and magnetic properties） of Ni-Co-Al with different Co/Al atomic ratios （RCo/Al） was investigated. Samples exhibit β and γ dual-phase structure. The γ phase grows coarse and the volume fraction of γ phase increases with the rise of RCo/Al. Besides, sample with high amount of γ phase content has smaller βgrains ow- ing to the pinning effect of γ phase. The martensite, transformed from β phase, is tetragonal L10 structure with a （111） twinning plane. The martensitic transformation temperature of samples ascends with increasing R co/Al owing to more Co embedded into the cell, which makes the valence electron concentration （e/a） of system rise. The satura- tion magnetization （Ms） of samples increases as Rco/Al rises because Co-rich 7 phase has excellent magnetic property. Meanwhile, both compressive and micro-hardness tests reveal that the samples containing more γ phase have excel- lent ductility due to the intrinsic good ductility nature of γ phase.展开更多
order to assess the promotional effects of La3+ on CO hydrogenation of Co/SiO2 catalyst, solvated metal atom impregnation (SMAI) method was used to prepare unpromoted 10% (mass fraction) Co/SiO2 and a series of La3+-p...order to assess the promotional effects of La3+ on CO hydrogenation of Co/SiO2 catalyst, solvated metal atom impregnation (SMAI) method was used to prepare unpromoted 10% (mass fraction) Co/SiO2 and a series of La3+-promoted 10% (mass fraction) Co/SiO2 catalyst with different La/Co atomic ratios (0.1, 0.3, 0.5). X-ray diffraction (XRD), and CO chemisorption measurements show that the cobalt particle size decreases as the La/Co ratios increase. X-ray photoelectron spectrescopy indicates that cobalt is in zero-valent state for all the samples. Catalytic test shows that the catalytic activity of La3+-promoted Co/SiO2 in CO hydrogenation is higher than that of unpromoted Co/SiO2, and enhances with the La/Co ratios increase. La3+ promotion also causes the enhanced selectivity of Co/SiO2 catalyst for higher hydrocarbon products.展开更多
文摘The diffusible hydrogen contents in precharged (Co,Fe) 3V alloy were measured. It is found that atomic ordering can not promote hydrogen penetration in the (Co,Fe) 3V alloy. The ultimate tensile strength (UTS) and ductilities in various condition were also investigated. The results show that the UTS and elongation of disordered alloy are higher than that of ordered one with fixed diffusible hydrogen content and (Co,Fe) 3V alloy with ordered structure is highly susceptible to the embrittlement in hydrogen gas. The factor which may affect the susceptibility to the embrittlement of (Co,Fe) 3V alloy in hydrogen gas is mainly due to that the atomic ordering may accelerate the kinetics of the catalytic reaction for the dissociation of molecular hydrogen into atomic hydrogen. However, it can not be roled out that atomic ordering intensifies planar slip and restricts cross slip at the grain boundaries and enhances the susceptibility of the alloy to hydrogen embrittlement.
文摘As a potential ferromagnetic shape memory alloy, Ni-Co-Al has excellent mechanical properties, large ma gentic-field-induced strain and high martensitic transformation temperature. The relationship between microstructure and performance （mechanical and magnetic properties） of Ni-Co-Al with different Co/Al atomic ratios （RCo/Al） was investigated. Samples exhibit β and γ dual-phase structure. The γ phase grows coarse and the volume fraction of γ phase increases with the rise of RCo/Al. Besides, sample with high amount of γ phase content has smaller βgrains ow- ing to the pinning effect of γ phase. The martensite, transformed from β phase, is tetragonal L10 structure with a （111） twinning plane. The martensitic transformation temperature of samples ascends with increasing R co/Al owing to more Co embedded into the cell, which makes the valence electron concentration （e/a） of system rise. The satura- tion magnetization （Ms） of samples increases as Rco/Al rises because Co-rich 7 phase has excellent magnetic property. Meanwhile, both compressive and micro-hardness tests reveal that the samples containing more γ phase have excel- lent ductility due to the intrinsic good ductility nature of γ phase.
文摘order to assess the promotional effects of La3+ on CO hydrogenation of Co/SiO2 catalyst, solvated metal atom impregnation (SMAI) method was used to prepare unpromoted 10% (mass fraction) Co/SiO2 and a series of La3+-promoted 10% (mass fraction) Co/SiO2 catalyst with different La/Co atomic ratios (0.1, 0.3, 0.5). X-ray diffraction (XRD), and CO chemisorption measurements show that the cobalt particle size decreases as the La/Co ratios increase. X-ray photoelectron spectrescopy indicates that cobalt is in zero-valent state for all the samples. Catalytic test shows that the catalytic activity of La3+-promoted Co/SiO2 in CO hydrogenation is higher than that of unpromoted Co/SiO2, and enhances with the La/Co ratios increase. La3+ promotion also causes the enhanced selectivity of Co/SiO2 catalyst for higher hydrocarbon products.
