Chapter 2. Oxide Coatings for Semiconductor Light Absorbers: Advanced Synthesis and Applications

Contamination of hazardous chemicals is currently considered one of the major environmental problems. The methods of purification of gaseous emissions depending on the physicochemical properties of pollutants, in particular dangerous chemical, their aggregate state, concentration in the gas environment are studied in this article. The effect of aerosol content such as dust and soot is analyzed as well as the efficiency of purification methods at different temperature intervals, methods of purification of multicomponent mixtures. The comparative characteristics of thermochemical, reagent, sorption and catalytic methods are given and the prospects of their application in filtering systems of stationary and mobile objects are evaluated. It has been proved that almost any organic compounds can be oxidized (mineralized) on the TiO2surface. In practice, any photocatalytic air purifier includes a porous TiO2 deposited carrier, which is irradiated with ultraviolet rays and through which air is purged. Photocatalysis is suitable for domestic use as it can occur at room temperature. For example, a thermocatalytic method of destroying harmful substances requires preheating the air to a temperature above 200 ° C. Photocatalysis destroys substances that penetrate even through activated carbon filters. Features of formation of oxide coatings by plasma-electrolytic oxidation of titanium alloys are considered. It is proposed to refine the design of collective defense systems on armored vehicles and stationary facilities with additional installation in the filter-absorber of the grid with the deposited layer of catalytic material, which will neutralize various types of dangerous chemicals due to photocatalytic air purification.

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Interfacial Interactions between Co‐based Cocatalysts and Semiconducting Light Absorbers for Solar‐Light‐Driven Redox Reactions

Solar RRL ◽

10.1002/solr.202100234 ◽

2021 ◽

Author(s):

Qing Guo ◽

Xiyuan Feng ◽

Z. Conrad Zhang ◽

Limin Huang

Keyword(s):

Redox Reactions ◽

Solar Light ◽

Interfacial Interactions ◽

Light Absorbers

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THE EFFECT OF ELECTROLYTE TEMPERATURE AND SEALING SOLUTION IN ANODIZING OPERATION ON HARDNESS AND WEAR BEHAVIOR OF 7075 -T6 ALUMINUM ALLOY

Surface Review and Letters ◽

10.1142/s0218625x18501433 ◽

2019 ◽

Vol 26 (02) ◽

pp. 1850143

Author(s):

SAEED NIYAZBAKHSH ◽

KAMRAN AMINI ◽

FARHAD GHARAVI

Keyword(s):

Weight Loss ◽

Wear Resistance ◽

Aluminum Alloy ◽

Wear Behavior ◽

Anodic Oxide ◽

Boiling Water ◽

Electrolyte Temperature ◽

Oxide Coatings ◽

Sodium Dichromate ◽

Pin On Disk

Anodic oxide coatings are applied on aluminum alloys in order to improve corrosion resistance and to increase hardness and wear resistance. In the current study, a hard anodic coating was applied on AA7075-T6 aluminum alloy. To survey the anodizing temperature (electrolyte temperature) effect, three temperatures, namely, [Formula: see text]C, 0∘C and 5∘C were chosen and the samples were sealed in boiling water and sodium dichromate to study the role of sealing. For measuring the oxide coatings porosity and hardness and also for comparing the samples’ wear resistance field-emission scanning electron microscopy (FESEM), microhardness test and pin-on-disk method were utilized, respectively. The results showed that by increasing the anodizing temperature, hardness and consequently wear resistance decreased so that hardness and weight loss in the samples with no sealing decreased from 460[Formula: see text]HV and 0.61[Formula: see text]mg at [Formula: see text]C to 405 and 358[Formula: see text]HV and 1.05 and 1.12[Formula: see text]mg at 0∘C and 5∘C, respectively, which is due to the porosity increment by increasing the anodizing temperature. Also, sealing in boiling water and dichromate contributed to soft phases and coating hydration, which resulted in a decrease in hardness and wear resistance. Hardness and weight loss in the coated samples at [Formula: see text]C decreased from 460[Formula: see text]HV and 0.61[Formula: see text]mg in the samples with no sealing to 435 and 417[Formula: see text]HV and 0.72 and 0.83[Formula: see text]mg in the samples sealed in boiling water and dichromate, respectively.

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Bacterial adhesion on amorphous and crystalline metal oxide coatings

Materials Science and Engineering C ◽

10.1016/j.msec.2015.07.031 ◽

2015 ◽

Vol 57 ◽

pp. 88-99 ◽

Cited By ~ 13

Author(s):

Argelia Almaguer-Flores ◽

Phaedra Silva-Bermudez ◽

Rey Galicia ◽

Sandra E. Rodil

Keyword(s):

Metal Oxide ◽

Bacterial Adhesion ◽

Oxide Coatings ◽

Crystalline Metal ◽

Metal Oxide Coatings

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Green Nanocoatings Based on the Deposition of Zirconium Oxide: The Role of the Substrate

Materials ◽

10.3390/ma14041043 ◽

2021 ◽

Vol 14 (4) ◽

pp. 1043

Author(s):

Vitor Bonamigo Moreira ◽

Anna Puiggalí-Jou ◽

Emilio Jiménez-Piqué ◽

Carlos Alemán ◽

Alvaro Meneguzzi ◽

...

Keyword(s):

Zirconium Oxide ◽

Active Sites ◽

Modified Electrodes ◽

Chemical Conversion ◽

Ceramic Materials ◽

Point Of View ◽

Oxide Coatings ◽

Alloying Element ◽

Substrate Nature

Herein, the influence of the substrate in the formation of zirconium oxide monolayer, from an aqueous hexafluorozirconic acid solution, by chemical conversion and by electro-assisted deposition, has been approached. The nanoscale dimensions of the ZrO2 film is affected by the substrate nature and roughness. This study evidenced that the mechanism of Zr-EAD is dependent on the potential applied and on the substrate composition, whereas conversion coating is uniquely dependent on the adsorption reaction time. The zirconium oxide based nanofilms were more homogenous in AA2024 substrates if compared to pure Al grade (AA1100). It was justified by the high content of Cu alloying element present in the grain boundaries of the latter. Such intermetallic active sites favor the obtaining of ZrO2 films, as demonstrated by XPS and AFM results. From a mechanistic point of view, the electrochemical reactions take place simultaneously with the conventional chemical conversion process driven by ions diffusion. Such findings will bring new perspectives for the generation of controlled oxide coatings in modified electrodes used, as for example, in the construction of battery cells; in automotive and in aerospace industries, to replace micrometric layers of zinc phosphate by light-weight zirconium oxide nanometric ones. This study is particularly addressed for the reduction of industrial waste by applying green bath solutions without the need of auxiliary compounds and using lightweight ceramic materials.

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