Сrystalline microcone coatings on titanium sponge.

Abstract

For the first time it was shown how to obtain microcone-shaped TiO2structures by means of anodizing of porous powder materials made of titanium sponge. It was established that during anodizing in 10 %Н2SO4+ 0,15 % HF electrolyte along with the growth of the X-ray amorphous nanoporous TiO2film a set of microcones with anatase crystalline structure is formed on the surface of titanium sponge powder particles. Microcones (height is up to 7m, base diameter is up to 5m) consist of multilayer nanoscale structures. Such structures are promising for the manufacture of new nanomaterials for catalytic and sensor devices.

Анодный Оксид Алюминия, Сформированный В Водных Растворах Хелатных Комплексных Соединений Цинка И Кобальта

“…Визуально представленные на рис. 3 образования напоминают объекты, изображенные на СЭМ изображениях в работах прошлых лет, посвященных анодированию алюминия в различных кислотах [49][50][51], в недавно опубликованной работе [20], а также микроконусы, растущие при анодировании титана [52,53]. Это наблюдение может свидетельствовать об общем характере причин, приводящих к возникновению таких образований.…”

“…Это наблюдение может свидетельствовать об общем характере причин, приводящих к возникновению таких образований. Вероятно, происходит локальное перераспределение плотности тока и концентрации различающихся по природе ионов, в той или иной мере упорядоченное, которое может приводить как к росту более или менее регулярно расположенных микровыступов [20,52,53], так и к образованию случайно расположенных пробоев [49][50][51].…”

Peculiar Porous Aluminum Oxide Films Produced via Electrochemical Anodizing in Malonic Acid Solution with Arsenazo-I Additive

“…The ratio of simultaneously occurring self-organized processes of metal oxidation with the formation of oxide and dissolution plays an important role in the formation of porous and tubular anodic oxides of valve metals. Different kinds of metal dissolution during anodic oxidation of aluminum and other valve metals lead to the formation of oxide films with different morphologies: barrier layers, quasi-regular porous layers, high degree self-ordering porous layers as well as tubular and nanocomposite structures [ 6 , 12 , 13 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 , 22 , 23 , 24 , 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ]. The anodizing electrolyte is, aside from other process parameters, the main factor that determines this morphology.…”

“…Barrier layers, which are interesting because of their dielectric properties [ 35 ], are formed in baths where oxide dissolution is slow [ 36 ]. The dissolving power of the electrolyte can be varied in two approaches: the introduction of ligands forming stable complex compounds with the ions of the anodized metal and the change in the pH value of the electrolyte [ 33 ], and the dissolving power of the electrolyte can be easily controlled by introducing small additions of fluoride ions that form stable complex compounds with the ions of the listed metals. Due to the oxide chemical properties of most refractory metals (titanium, hafnium, niobium, tantalum, tungsten, vanadium, and zirconium) [ 37 ], the dissolving power of the electrolyte can be easily controlled by introducing small additions of fluoride ions that form stable complex compounds with the ions of the listed metals [ 38 ].…”

Anodizing of Hydrogenated Titanium and Zirconium Films

“…Anodic oxide films of aluminum (Al) and other valve metals (Ta, Nb, Ti, Hf, Zr, and W) are promising materials for electronic technology [1][2][3][4][5][6]; therefore, electrochemical behavior was investigated [7][8][9][10][11][12][13][14][15][16][17][18][19][20][21]. At the same time, under certain conditions, all these metals (Al [22], Ta [23], Nb [24], Ti [25], Hf [26], Zr [27], W [28], and others [29]) absorb significant amounts of hydrogen, and the volume of the absorbed hydrogen is several orders of magnitude larger than the volume of the metal.…”