anodizing
otherwise anodising
(rus. анодирование otherwise электрохимическое оксидирование)
— electrochemical surface oxidation of metals, alloys and semiconductors.
Description
The technology of anodizing aluminium, titanium, tantalum, niobium, silicon, germanium, and gallium arsenide is widespread. Normally anodizing is performed at a constant current in galvanostatic or potentiostatic mode.
By the type of oxygen-containing medium that fills the interelectrode space there exist the following types: anodizing in aqueous electrolyte solutions, anodizing in molten salts, plasma anodizing and plasma electrolytic oxidation.
Anodizing in aqueous electrolyte solutions is widely used in the electronics industry for the manufacturing of (electrolytic, oxide-semiconductor, metal oxide) capacitors.
Anodizing in molten salts is used to prepare oxide films of increased thickness and microhardness, specifically on copper and iron surfaces.
Plasma anodizing is widely used in microelectronics, as the process is technologically compatible with other operations of the integrated vacuum process, and for fabrication of thin-film components with tunnelling devices (Josephson elements, metal base triodes, optoelectronic components), dielectric layers in capacitors, surface passivation of integrated circuits and intercomponent isolation.
Combination of a unique porous structure (straight pores with controlled diameter) with high thermal, mechanical and chemical stability makes anodic aluminium oxide films (see Fig.) attractive for various applications in filtration and separation of mixtures, data storage, sensors and for synthesis of one-dimensional nanostructures (see nano-reactor, 1D).
By the type of oxygen-containing medium that fills the interelectrode space there exist the following types: anodizing in aqueous electrolyte solutions, anodizing in molten salts, plasma anodizing and plasma electrolytic oxidation.
Anodizing in aqueous electrolyte solutions is widely used in the electronics industry for the manufacturing of (electrolytic, oxide-semiconductor, metal oxide) capacitors.
Anodizing in molten salts is used to prepare oxide films of increased thickness and microhardness, specifically on copper and iron surfaces.
Plasma anodizing is widely used in microelectronics, as the process is technologically compatible with other operations of the integrated vacuum process, and for fabrication of thin-film components with tunnelling devices (Josephson elements, metal base triodes, optoelectronic components), dielectric layers in capacitors, surface passivation of integrated circuits and intercomponent isolation.
Combination of a unique porous structure (straight pores with controlled diameter) with high thermal, mechanical and chemical stability makes anodic aluminium oxide films (see Fig.) attractive for various applications in filtration and separation of mixtures, data storage, sensors and for synthesis of one-dimensional nanostructures (see nano-reactor, 1D).
Illustrations
|
Membrane on the basis of anodized aluminum oxide with the higher-order system. Authors: K. S. Napolskii, A. A. Eliseev. Lomonosov Moscow State University, Department of Materials Science. |
Author
- Naymushina Daria A.
Sources
- Aver'janov E. E. Handbook of anodization (in Russian). — Moscow: Mashinostroenie, 1988. — 224 p. Belen'kijj M. A., Ivanov A.F. Handbook of electrodeposition of metallic coatings (in Russian). — Moscow: Metallurgija, 1985. — 288 p.
- Lee W., Ji R., Gosele U., Nielsch K. Fast fabrication of long-range ordered porous alumina membranes by hard anodization // Nature Materials. 2006. V. 5, №9. P. 741–747.
- Petukhov D. I., Eliseev A. A., Kolesnik I. V. et al. Formation mechanism and packing options in tubular anodic titania films // Microporous and Mesoporous Materials. 2008. V. 114. P. 440–447.