Author
M. Sakairi
Bio: M. Sakairi is an academic researcher from Hokkaido University. The author has contributed to research in topics: Anodizing & Corrosion. The author has an hindex of 21, co-authored 26 publications receiving 958 citations.
Topics: Anodizing, Corrosion, Materials science, Oxide, Metallurgy
Papers
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TL;DR: In this article, anodising of Ta-Al and Nb-Al bilayer samples has been performed in organic and inorganic acid electrolytes for porous alumina formation and the shape and mutual arrangement of the anodic oxide nanostructures depend on the nature of the underlying metal.
105 citations
TL;DR: In this article, the authors examined the effect of sodium tetraborate concentration on the formation and breakdown characteristics of barrier oxide films by using inductively coupled plasma atomic emission spectrometry, electroluminescence/photoluminecence measurements, scanning electron microscopy, transmission electron microscope, and electrochemical impedance spectroscopy.
Abstract: Highly pure aluminum was anodized at a constant current density of 25 A m -2 at 293 K in 0.5 M boric acid/0, 0.005, or 0.05 M sodium tetraborate solutions, to examine the effect of sodium tetraborate concentration on the formation and breakdown characteristics of barrier oxide films by using inductively coupled plasma atomic emission spectrometry, electroluminescence/photoluminescence measurements, scanning electron microscopy, transmission electron microscopy, and electrochemical impedance spectroscopy. In boric acid/borate solutions, a crystalline alumina formed locally in the middle of the amorphous oxide film. Above the crystalline alumina, a void is formed and may lead to a breakdown of the oxide film at 420 to 540 V. In boric acid solution, an amorphous oxide film grew until 1180 V with the formation and development of imperfections and with enhancement of electroluminescence and gas evolution. At imperfections. the oxide/solution interface was convex and the oxide/metal interface curved in the opposite direction. This deformation is attributed to high-pressure O 2 evolved in the pores of imperfections and to the local formation and dissolution of oxide. The breakdown of the oxide film started when the O 2 evolution and oxide dissolution at imperfections become predominant. The mechanism of formation and breakdown of the anodic film in the boric acid/borate solutions is discussed in terms of pH buffering of the anodizing solution, and the electronic structure of anodic oxide films is correlated with electroluminescence and photoluminescence spectrum results.
85 citations
TL;DR: In this paper, an anodic oxide film was formed at the interface between zirconium oxide and the aluminum substrate during anodizing, which was composed of an inner Al 2 O 3 layer and an outer Al-Zr composite oxide layer.
80 citations
TL;DR: In this article, the authors consider the applicability of second phase particles during anodizing of commercial alloys and propose improved anodization and related surface treatment processes to enhance the performance of aluminium alloys.
Abstract: Anodizing is used widely in the surface treatment of aluminium alloys for aerospace applications. Considers recent advances in understanding of the influences of alloying elements in anodizing of aluminium alloys and, in particular, their applicability to second phase particles during anodizing of commercial alloys. Through more precise knowledge of the response of second phase materials to anodic polarization, improved anodizing and related surface treatment processes may be developed in order to enhance the performance of aluminium alloys.
80 citations
TL;DR: In this article, an Al/Ta bilayer is prepared by successive sputterdeposition of a 150nm tantalum layer and a 180-nm aluminium layer onto a silicon wafer, at voltages of up to 53 V, which generates a 260-nm alumina film with well-ordered nanoporous structure.
62 citations
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1,033 citations
TL;DR: In this article, the incorporation of nanoparticles in the hybrid sol-gel systems increases the corrosion protection properties due to lower porosity and lower cracking potential along with enhancement of the mechanical properties.
Abstract: Sol–gel derived films exhibit a high potential as substitutes for the environmentally unfriendly chromate metal-surface pre-treatment methods. Inorganic sol–gel derived films offer good adhesion between metals and organic paint. However, they cannot provide adequate corrosion protection due to their high crack-forming potential. Introduction of an organic component to an inorganic sol–gel system leads to the formation of thicker, more flexible and functionalized films with enhanced compatibility to different organic top coatings. Incorporation of nanoparticles in the hybrid sol–gel systems increases the corrosion protection properties due to lower porosity and lower cracking potential along with enhancement of the mechanical properties. Furthermore, the incorporation of inorganic nanoparticles can be a way to insert corrosion inhibitors, preparing inhibitor nanoreservoirs for “self-repairing” pre-treatments with controlled release properties.
467 citations
TL;DR: A vertically aligned Ta(3)N(5) nanorod photoelectrode is fabricated by through-mask anodization and nitridation for water splitting to yield a high photocurrent density and one of the highest activities reported for photoanodes so far.
Abstract: A vertically aligned Ta(3)N(5) nanorod photoelectrode is fabricated by through-mask anodization and nitridation for water splitting. The Ta(3)N(5) nanorods, working as photoanodes of a photoelectrochemical cell, yield a high photocurrent density of 3.8 mA cm(-2) at 1.23 V versus a reversible hydrogen electrode under AM 1.5G simulated sunlight and an incident photon-to-current conversion efficiency of 41.3% at 440 nm, one of the highest activities reported for photoanodes so far.
351 citations
TL;DR: This paper provides an overview of the employment of anodization for nanotubes fabricated on the surface of titanium, titanium alloys and titanium alloying metals such as niobium, tantalum and zirconium metal implants and assesses this topical research to indicate how changes in anodizing conditions influence nanotube characteristics.
345 citations
TL;DR: This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.
Abstract: The anodization of aluminum is an electro-chemical process that changes the surface chemistry of the metal, via oxidation, to produce an anodic oxide layer. During this process a self organized, highly ordered array of cylindrical shaped pores can be produced with controllable pore diameters, periodicity and density distribution. This enables anodic aluminum oxide (AAO) membranes to be used as templates in a variety of nanotechnology applications without the need for expensive lithographical techniques. This review article is an overview of the current state of research on AAO membranes and the various applications of nanotechnology that use them in the manufacture of nano-materials and devices or incorporate them into specific applications such as biological/chemical sensors, nano-electronic devices, filter membranes and medical scaffolds for tissue engineering.
336 citations