Chromate conversion coating ≈ Chromate conversion coating
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Chromate replacement: what does the future hold? Open
The ubiquitous use of chromium and its derivatives as corrosion preventative compounds accelerated rapidly after the second industrial revolution, with such compounds now integral to modern society. However, the detrimental impact of chrom…
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Review on Corrosion Inhibitors for Oil and Gas Corrosion Issues Open
The pipeline system in the oil and gas industry is the heart for transportation of crude and refined petroleum. Nevertheless, continuous exposure of the pipeline surfaces to impurities and sources of corrosion such as sulfur and chromate i…
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Review—Conversion Coatings Based on Zirconium and/or Titanium Open
There is a growing interest in conversion coatings based on titanium and/or zirconium as the result of the health and environmental issues associated with legacy chromate and phosphate conversion coatings. Any alternative technology should…
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Hexavalent chromium quantification in solution: Comparing direct UV–visible spectrometry with 1,5-diphenylcarbazide colorimetry Open
Quantification of Cr(VI) in an aqueous solution is conducted by direct UV–visible spectrophotometry based on the yellow coloring of the chromate ion. Measurements show that absorption follows the Beer–Lambert law over a wide range of conce…
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Layered double hydroxides (LDHs) as functional materials for the corrosion protection of aluminum alloys: A review Open
The search for new alternatives to replace chromate-based coatings is a matter of great importance. Since their official ban due to the raised concerns of hexavalent chromium to the human health and the environment, significant efforts hav…
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Reduction of Hexavalent Chromium and Detection of Chromate Reductase (ChrR) in Stenotrophomonas maltophilia Open
An Gram negative strain of S. maltophilia, indigenous to environments contaminated by Cr(VI) and identified by biochemical methods and 16S rRNA gene analysis, reduced chromate by 100%, 98–99% and 92% at concentrations in the 10–70, 80–300,…
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Review article. Adverse hematological effects of hexavalent chromium: an overview Open
Workers of tanneries, welding industries, factories manufacturing chromate containing paints are exposed to hexavalent chromium that increas¬es the risk of developing serious adverse health effects. This review elucidates the mode of actio…
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Chromate-free chemical conversion coatings for aluminum alloys Open
Corrosion of metallic components represents a major issue in the aeronautical sector, giving rise to safety concerns and significant financial damages. Conversion coatings (CC) based on hexavalent chromium provide exceptional corrosion pro…
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Ultrafiltration membrane for effective removal of chromium ions from potable water Open
The objective of the present work was to investigate the efficacy of indigenously developed polyacrylonitrile (PAN) based ultrafiltration (UF) membrane for chromium ions removal from potable water. The hydrolyzed PAN membranes effectively …
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Macrocyclic squaramides: anion receptors with high sulfate binding affinity and selectivity in aqueous media Open
Macrocyclic squaramide derivatives bind sulfate ions with high selectivity and affinity in aqueous mixtures.
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Flash-PEO as an alternative to chromate conversion coatings for corrosion protection of Mg alloy Open
In the present work, a flash-PEO coating is developed on AZ31B alloy in a combination of silicate, phosphate, and fluoride based electrolyte in order to offer a green alternative to chromate conversion coatings. Multilevel active protectio…
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Trivalent chromium conversion coating formation on aluminium Open
The formation of a trivalent conversion coating on aluminium has been investigated using analytical electron microscopy, atomic force microscopy, ion beam analysis, glow discharge optical emission spectroscopy, Raman spectroscopy and X-ray…
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Advancements in corrosion protection for aerospace aluminum alloys through surface treatment Open
This review delves into the dynamic field of corrosion protection for aerospace aluminum alloys, emphasizing the evolution of surface treatment technologies. Aluminum alloys, central to the aerospace industry due to their optimal blend of …
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TiO2-based catalysts for photocatalytic reduction of aqueous oxyanions: State-of-the-art and future prospects Open
Nowadays, an increasing discharge of oxyanions to the natural environment has been attracting worldwide attention. TiO2-based photocatalysis is regarded as one of the most promising technologies for the conversion of toxic oxyanions (such …
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Large dipole moment induced efficient bismuth chromate photocatalysts for wide-spectrum driven water oxidation and complete mineralization of pollutants Open
Herein, a wide-spectrum (∼678 nm) responsive Bi8(CrO4)O11 photocatalyst with a theoretical solar spectrum efficiency of 42.0% was successfully constructed. Bi8(CrO4)O11 showed highly efficient and stable photocatalytic water oxidation acti…
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On the structure of high performance anticorrosive PMMA–siloxane–silica hybrid coatings Open
Environmentally compliant organic–inorganic hybrid coatings for efficient corrosion protection of metallic surfaces are potential alternatives to the current method based on chromate passivation.
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Sulfate and chromate increased each other's uptake and translocation in As-hyperaccumulator Pteris vittata Open
We investigated the effects of chromate (CrVI) and sulfate on their uptake and translocation in As-hyperaccumulator Pteris vittata. Plants were exposed to 1) 0.1 mM CrVI and 0, 0.25, 1.25 or 2.5 mM sulfate or 2) 0.25 mM sulfate and 0, 0.5,…
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Review of Cr-Free Coatings for the Corrosion Protection of Aluminum Aerospace Alloys Open
Aluminum alloys are known to have many advantages (e.g., light weight and low cost) but they are not immune to corrosion. So, it is important to assess their corrosion behavior, in particular under atmospheric conditions. To protect alumin…
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Bioremediation of Hexavalent Chromium by Chromium Resistant Bacteria Reduces Phytotoxicity Open
Chromium (Cr) (VI) has long been known as an environmental hazard that can be reduced from aqueous solutions through bioremediation by living cells. In this study, we investigated the efficiency of reduction and biosorption of Cr(VI) by ch…
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Formation of a Trivalent Chromium Conversion Coating on AA2024-T351 Alloy Open
The formation of a trivalent chromium conversion coating on AA2024-T351 aluminum alloy has been studied using electron microscopy, scanning Kelvin probe force microscopy, ion beam analysis and X-ray photoelectron spectroscopy (XPS). The co…
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Recent Development in Phosphonic Acid-Based Organic Coatings on Aluminum Open
Research on corrosion protection of aluminum has intensified over the past decades due to environmental concerns regarding chromate-based conversion coatings and also the higher material performance requirements in automotive and aviation …
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Response surface methodology as a powerful tool to optimize the synthesis of polymer-based graphene oxide nanocomposites for simultaneous removal of cationic and anionic heavy metal contaminants Open
Nanocomposites containing graphene oxide (GO), polyethyleneimine (PEI), and chitosan (CS) were synthesized for chromium(vi) and copper(ii) removal from water.
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Molecular-Scale Understanding of Sulfate Exchange from Schwertmannite by Chromate Versus Arsenate Open
Schwertmannite effectively sorbs chromate (Cr(VI)), yet the sorption mechanisms remain elusive. We determined the Cr(VI) sorption mechanisms on schwertmannite at pH 3.2 and 5 using combined macroscopic sorption experiments with molecular-s…
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High dispersions of nano zero valent iron supported on biochar by one-step carbothermal synthesis and its application in chromate removal Open
A one-step carbothermal synthesis and characterization of biochar-supported nanoscale zero-valent iron (nZVI/BC) was performed for the removal of hexavalent chromium (Cr(vi)) from aqueous solution.
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Artificial Neural Networks (ANNs) and Response Surface Methodology (RSM) Approach for Modelling the Optimization of Chromium (VI) Reduction by Newly Isolated<i>Acinetobacter radioresistens</i>Strain NS-MIE from Agricultural Soil Open
Numerous technologies and approaches have been used in the past few decades to remove hexavalent chromium (Cr[VI]) in wastewater and the environment. However, these conventional technologies are not economical and efficient in removing Cr(…
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Role of phosphate, silicate and aluminate in the electrolytes on PEO coating formation and properties of coated Ti6Al4V alloy Open
A comparison of PEO layers on Ti6Al4V alloy formed in phosphate, aluminate and silicate-based electrolytes respectively, has been made to reveal the influence of the electrolyte composition on the formation process. The phosphate-based ele…
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Bioremediation of hexavalent chromium (VI) by a soil-borne bacterium,<i>Enterobacter cloacae</i>B2-DHA Open
Chromium and chromium containing compounds are discharged into the nature as waste from anthropogenic activities, such as industries, agriculture, forest farming, mining and metallurgy. Continued disposal of these compounds to the environm…
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Hexavalent chromium reduction from real electroplating wastewater by chemical precipitation Open
The immense use of chromium in the electroplating process leads to the discharge of hexavalent chromium in its effluent. Since Cr(VI) is highly toxic, its exposure poses an acute risk of health. On the contrary, Cr(III) which is naturally …
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Smart Functionalization of Ceramic-Coated AZ31 Magnesium Alloy Open
Providing materials with smart functionalities such as self-healing properties is primarily a domain for organic materials, although their applicability is restricted to mild environments and loads because of poor thermal and mechanical pr…
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Lead chromate detected as a source of atmospheric Pb and Cr (VI) pollution Open
Spherical black carbon aggregates were frequently observed in dust dry deposition in Daejeon, Korea. They were tens of micrometers in diameter and presented a mixture of black carbon and several mineral phases. Transmission electron micros…