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H. Karakurkchi et al.
with solutions containing doping components and their subsequent treatment at high
temperatures. But this does not allow achieving high adhesion of mixed oxide layer. In
this regard, technical modes are of great interest, which make it possible to combine
the surface homogenization of Al alloys with the formation of mixed conversion
oxide coatings containing transition metals [8, 9]. Suchwise, strong adhesion and
even distribution of the oxide layer over the surface are ensured.
Metal oxides are used as catalysts in many technological processes in gas and
liquid media, as electrode materials in electrochemical synthesis and chemical current
sources [5, 10]. Of particular interest are non-stoichiometric oxides, because for
both the electrochemical and chemical reactions rate increases with deviation from
stoichiometry of surface oxides.
Recently, works of foreign and domestic researchers are devoted to the processes
of oxidation of passive metals in high-energy fields (anode-spark or micro-arc
modes).
Varying the composition of the working solutions and processing conditions
allows flexible control over the process of producing oxide coatings and the composition of film materials. Also, PEO method allows to obtain a uniform catalytically
active layer on parts of complex profile and shape, and significant sizes. This greatly
expands conversion of mixed oxide systems usage and application. Eco-friendly
processing solutions and fairly simple equipment for PEO allow considering such
treatment as safe resource-saving and ecological technology for obtaining oxide
coatings with a broad area of application [10, 11].
Conversion coatings on different valve metals, predominantly aluminum alloys,
possess catalytic properties which were widely used in the heterogeneous catalysis
[12].
Mixed metal-oxide systems are known as the most promising for environmental
improvements. This is due to the catalytic properties of such compounds facilitated
by the complex composition, in particular, different chemical substances formation,
incorporation of dopants, deviation oxides from stoichiometric ratio. Above oxide
systems are characterized by a long service life at high pressures and temperatures,
which is extremely important for cleaning and neutralizing toxic emissions. High
mechanical strength, corrosion resistance, reliability and ability to restore provide a
long operational lifecycle for coated parts and carriers.
Manganese as well as its compounds occupies a special place among the catalysts.
Particularly high interest in manganese (IV) oxide is due to the large number of its
varieties differing by chemical and electrochemical properties and widespread use
in many technological processes [7, 13].
The purpose of this study is to improve the technology of Aluminum alloys
oxidation in alkaline solutions to obtain manganese-containing coatings with high
corrosion resistance and activity in gaseous wastes purification.
H. Karakurkchi et al.
with solutions containing doping components and their subsequent treatment at high
temperatures. But this does not allow achieving high adhesion of mixed oxide layer. In
this regard, technical modes are of great interest, which make it possible to combine
the surface homogenization of Al alloys with the formation of mixed conversion
oxide coatings containing transition metals [8, 9]. Suchwise, strong adhesion and
even distribution of the oxide layer over the surface are ensured.
Metal oxides are used as catalysts in many technological processes in gas and
liquid media, as electrode materials in electrochemical synthesis and chemical current
sources [5, 10]. Of particular interest are non-stoichiometric oxides, because for
both the electrochemical and chemical reactions rate increases with deviation from
stoichiometry of surface oxides.
Recently, works of foreign and domestic researchers are devoted to the processes
of oxidation of passive metals in high-energy fields (anode-spark or micro-arc
modes).
Varying the composition of the working solutions and processing conditions
allows flexible control over the process of producing oxide coatings and the composition of film materials. Also, PEO method allows to obtain a uniform catalytically
active layer on parts of complex profile and shape, and significant sizes. This greatly
expands conversion of mixed oxide systems usage and application. Eco-friendly
processing solutions and fairly simple equipment for PEO allow considering such
treatment as safe resource-saving and ecological technology for obtaining oxide
coatings with a broad area of application [10, 11].
Conversion coatings on different valve metals, predominantly aluminum alloys,
possess catalytic properties which were widely used in the heterogeneous catalysis
[12].
Mixed metal-oxide systems are known as the most promising for environmental
improvements. This is due to the catalytic properties of such compounds facilitated
by the complex composition, in particular, different chemical substances formation,
incorporation of dopants, deviation oxides from stoichiometric ratio. Above oxide
systems are characterized by a long service life at high pressures and temperatures,
which is extremely important for cleaning and neutralizing toxic emissions. High
mechanical strength, corrosion resistance, reliability and ability to restore provide a
long operational lifecycle for coated parts and carriers.
Manganese as well as its compounds occupies a special place among the catalysts.
Particularly high interest in manganese (IV) oxide is due to the large number of its
varieties differing by chemical and electrochemical properties and widespread use
in many technological processes [7, 13].
The purpose of this study is to improve the technology of Aluminum alloys
oxidation in alkaline solutions to obtain manganese-containing coatings with high
corrosion resistance and activity in gaseous wastes purification.