The corrosion resistance of weathering bridge steels containing conventional contents of Ni(0.20 wt%, 0.42 wt%, 1.50 wt%) and a higher content of Ni(3.55 wt%) in a simulated hot and humid coastal-industrial atmosphere...The corrosion resistance of weathering bridge steels containing conventional contents of Ni(0.20 wt%, 0.42 wt%, 1.50 wt%) and a higher content of Ni(3.55 wt%) in a simulated hot and humid coastal-industrial atmosphere was investigated by corrosion depth loss, scanning electron microscopy–energy-dispersive X-ray spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical methods. The results showed that, with increasing Ni content, the mechanical properties of the bridge steel were markedly improved, the welding parameters were satisfactory at room temperature, and the corrosion resistance was enhanced. When the Ni content was low(≤0.42 wt%), the crystallization process of the corrosion products was substantially promoted, enhancing the stability of the rust layer. When the Ni content was higher(~3.55 wt%), the corrosion reaction of the steel quickly reached a balance, because the initial rapid corrosion induced the formation of a protective rust layer in the early stage. Simultaneously, NiO and NiFe_2O_4 were generated in large quantities; they not only formed a stable, compact, and continuous oxide protective layer, but also strongly inhibited the transformation process of the corrosion products. This inhibition reduced the structural changes in the rust layer, thereby enhancing the protection. However, when the Ni content ranged from 0.42 wt% to 1.50 wt%, the corrosion resistance of the bridge steel increased only slightly.展开更多
Three new complexes [Ni(H2L)][Fe(CN)(5)(NO)](2)(.)6H(2)O (1), [Ni(H2L)][Fe(CN)(5)(NO)](2)(.)4H(2)O (2) and [Cu(H2L)][Fe-(CN)(5)(NO)](2)(.)4H(2)O (3) (L=3,10-bis(2-aminoethyl)-1,3,5, 8,10,12-hexaazacyclotetradecane) ar...Three new complexes [Ni(H2L)][Fe(CN)(5)(NO)](2)(.)6H(2)O (1), [Ni(H2L)][Fe(CN)(5)(NO)](2)(.)4H(2)O (2) and [Cu(H2L)][Fe-(CN)(5)(NO)](2)(.)4H(2)O (3) (L=3,10-bis(2-aminoethyl)-1,3,5, 8,10,12-hexaazacyclotetradecane) are prepared and characterized by IR, elemental analyses and single-crystal X-ray analyses, indicating that they are the first examples of trinuclear nitroprusside-bridged MFe2(M = Cu and Ni) complexes. In the three complexes, the central metal atoms (M) are all six-coordinated by the nitrogen atoms from the macrocyclic ligand and two cyano-bridges at the trans-positions to form distorted octahedral configurations. The axial N-M-N linkage is nearly vertical to the equatorial plane defined by four coordinating N atoms of macrocyclic ligand. The Cequivalent toN-Ni bond angle of 172.6degrees in complex 1 is apparently larger than those in complexes 2 and 3 (152.57degrees and 136.37degrees, respectively). The three complexes are all connected by hydrogen bonds into 3D networks. This study shows that the cyano-bridged trinuclear species could be generated via the control of the charge of the building blocks.展开更多
基金financially supported by the National Natural Science Foundation of China (No. 51304040)the Fundamental Research Funds for the Central Universities (No. N150204008)
文摘The corrosion resistance of weathering bridge steels containing conventional contents of Ni(0.20 wt%, 0.42 wt%, 1.50 wt%) and a higher content of Ni(3.55 wt%) in a simulated hot and humid coastal-industrial atmosphere was investigated by corrosion depth loss, scanning electron microscopy–energy-dispersive X-ray spectroscopy, Raman spectroscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and electrochemical methods. The results showed that, with increasing Ni content, the mechanical properties of the bridge steel were markedly improved, the welding parameters were satisfactory at room temperature, and the corrosion resistance was enhanced. When the Ni content was low(≤0.42 wt%), the crystallization process of the corrosion products was substantially promoted, enhancing the stability of the rust layer. When the Ni content was higher(~3.55 wt%), the corrosion reaction of the steel quickly reached a balance, because the initial rapid corrosion induced the formation of a protective rust layer in the early stage. Simultaneously, NiO and NiFe_2O_4 were generated in large quantities; they not only formed a stable, compact, and continuous oxide protective layer, but also strongly inhibited the transformation process of the corrosion products. This inhibition reduced the structural changes in the rust layer, thereby enhancing the protection. However, when the Ni content ranged from 0.42 wt% to 1.50 wt%, the corrosion resistance of the bridge steel increased only slightly.
文摘Three new complexes [Ni(H2L)][Fe(CN)(5)(NO)](2)(.)6H(2)O (1), [Ni(H2L)][Fe(CN)(5)(NO)](2)(.)4H(2)O (2) and [Cu(H2L)][Fe-(CN)(5)(NO)](2)(.)4H(2)O (3) (L=3,10-bis(2-aminoethyl)-1,3,5, 8,10,12-hexaazacyclotetradecane) are prepared and characterized by IR, elemental analyses and single-crystal X-ray analyses, indicating that they are the first examples of trinuclear nitroprusside-bridged MFe2(M = Cu and Ni) complexes. In the three complexes, the central metal atoms (M) are all six-coordinated by the nitrogen atoms from the macrocyclic ligand and two cyano-bridges at the trans-positions to form distorted octahedral configurations. The axial N-M-N linkage is nearly vertical to the equatorial plane defined by four coordinating N atoms of macrocyclic ligand. The Cequivalent toN-Ni bond angle of 172.6degrees in complex 1 is apparently larger than those in complexes 2 and 3 (152.57degrees and 136.37degrees, respectively). The three complexes are all connected by hydrogen bonds into 3D networks. This study shows that the cyano-bridged trinuclear species could be generated via the control of the charge of the building blocks.
