Corrosion of nanocrystalline and coarse-grained nickel-iron (Ni-Fe) alloys in neutral and alkaline sulfate environments

Environmental Stability of Actinide Oxides Mapped by Integrated and Accurate First-Principles Calculations

“…The above-mentioned unavoidable technical and physical issues encountered by experiments can be circumvented by the first-principles calculations based on density functional theory (DFT), which can yield the accurate Δ f G values for various transition-metal oxides and hydroxides if a precise enough electronic interaction potential (called as electronic density functional in DFT) is applied. ,,− The recently simulated transition-metal Poubaix diagrams not only can comprehensively explain a lot of electrochemical observations reported in previous decades but also have been widely used by many recent electrochemical experiments in the fields of, e.g., corrosion, catalysis, and clean energy to guide the design, synthesis, and characterization analysis of various transition-metal compounds. − Those new first-principles diagrams even have been used in the geological field to understand the rock weathering mechanisms in acid rains on both the ancient Earth and Mars, e.g., the dissolution of Ni oxides and the formation of magnetite (a Fe 3 O 4 -based mineral). ,, The first-principles electrochemical phase diagrams can be further used to study more complex transition-metal systems, e.g., conventional Ni–Cr alloys, multiprincipal element alloys, , complex compounds, and nanoscale passivating films, and have successfully helped precisely understand many passivation, corrosion, and precipitation behaviors, as well as their dependence on both material state and environmental condition. Such success in the thermodynamic and electrochemical calculations of transition-metal systems encourages the use of DFT to obtain reliable Δ f G data for all possible actinide oxides, which can bring the fundamental and historical contribution to the related nuclear fields.…”

Elemental partitioning and corrosion resistance of Ni–Cr alloys revealed by accurate ab-initio thermodynamic and electrochemical calculations

“…High-fidelity calculations using exact nonlocal exchange potentials can be used to obtain accurate Δ f G values, from which reliable Pourbaix diagrams for transition-metal systems can be constructed and validated 36,37,39,40 . The first-principles Poubaix diagrams for transition metals have also been widely referred to by many recent electrochemical experiments in the fields of, e.g., corrosion [41][42][43][44][45] , catalysis, and energy [46][47][48][49][50][51][52][53][54] , where these diagrams guide the design and characterization of many related materials, and even have been applied to understand geological processes (rock weathering in acid rains) on both the ancient Earth and Mars 55,56 .…”

Caracterização Por Ebsd De Aços Inoxidáveis Uns S32304 E Uns S32750 Submetidos a Diferentes Tratamentos Térmicos

“…Esta observação está em acordo com a literatura [152,153,104] que aborda do ponto de vista prático sobre o conceito da junção tripla ou múltipla ser uma região muito mais propensa a corrosão. É proposto por diversos autores os fatores que influenciam nessa região a corrosão, dentre eles; região de alta energia com elevados teores de impurezas [154], aspectos geométricos onde o ataque na superfície do metal poderia abrir um caminho unidimensional o qual poderia favorecer a corrosão por pites [155] e consequentemente uma reação autocatalítica e região empobrecida de elementos fundamentais para formação e estabilização do filme passivo [156].…”