The corrosion behavior of the nitinol alloy was studied in various corrosion media of different Cl^- ion concentrations. The results demonstrate that the Cl^- ion concentration has significant influences on the corros...The corrosion behavior of the nitinol alloy was studied in various corrosion media of different Cl^- ion concentrations. The results demonstrate that the Cl^- ion concentration has significant influences on the corrosion behavior of the nitinol alloy. In order to enhance the corrosion resistance, protective films were generated on the surface of the nitinol alloy by means of the electrochemical passivation method, for which five different electrolytic solutions were investigated. The surface analysis indicates full growth of all samples passivated in the different electrolytic solutions with layers, however, showing different morphological features. Without any defects like micro-cracks and pores, the surface of the samples passivated in the molybdate solution turns out smoother and denser than those passivated in other solutions. It is shown that the electro-chemical passivation will reduce Ni content but increase Ti content in the surface, reaching the Mole ratio of Ti：Ni = 9.01：1 on the outermost surface. Potentiodynamic polarization test demonstrates that the samples electrochemically passivated in the molybdate solution present a significant increase in breakdown potential due to titanium enrichment on the outermost surface.展开更多
As an important functional material,Bi_(2)O_(3)is found in seven polymorphs.We systematically analyze the transformation fromα-,β-andε-toδ-Bi_(2)O_(3)by using crystallographic group theory and structural simulatio...As an important functional material,Bi_(2)O_(3)is found in seven polymorphs.We systematically analyze the transformation fromα-,β-andε-toδ-Bi_(2)O_(3)by using crystallographic group theory and structural simulations.A transition phase is proved to exist in the transformation from theα-,β-andε-Bi_(2)O_(3)toδ-Bi2 Os.The transition phase is supposed to be tetragonal phase Bi_(2)O_(2.7)(Z=2)with the 139th I 4/m 2/m 2/m space group.展开更多
基金Local Governmental Foundation of Guizhou province (2142005)
文摘The corrosion behavior of the nitinol alloy was studied in various corrosion media of different Cl^- ion concentrations. The results demonstrate that the Cl^- ion concentration has significant influences on the corrosion behavior of the nitinol alloy. In order to enhance the corrosion resistance, protective films were generated on the surface of the nitinol alloy by means of the electrochemical passivation method, for which five different electrolytic solutions were investigated. The surface analysis indicates full growth of all samples passivated in the different electrolytic solutions with layers, however, showing different morphological features. Without any defects like micro-cracks and pores, the surface of the samples passivated in the molybdate solution turns out smoother and denser than those passivated in other solutions. It is shown that the electro-chemical passivation will reduce Ni content but increase Ti content in the surface, reaching the Mole ratio of Ti：Ni = 9.01：1 on the outermost surface. Potentiodynamic polarization test demonstrates that the samples electrochemically passivated in the molybdate solution present a significant increase in breakdown potential due to titanium enrichment on the outermost surface.
基金Supported by the National Natural Science Foundation of China under Grant Nos 51072012 and 60776067。
文摘As an important functional material,Bi_(2)O_(3)is found in seven polymorphs.We systematically analyze the transformation fromα-,β-andε-toδ-Bi_(2)O_(3)by using crystallographic group theory and structural simulations.A transition phase is proved to exist in the transformation from theα-,β-andε-Bi_(2)O_(3)toδ-Bi2 Os.The transition phase is supposed to be tetragonal phase Bi_(2)O_(2.7)(Z=2)with the 139th I 4/m 2/m 2/m space group.
