chromate conversion coating is applied on aluminum 6061. the optimum conditions for chromate bath composition and immersion time are also obtained for standard requirements provision such as corrosion resistance in salt spray test, electrical resistance and coating quality. the applied coatings are electrochemically tested in sea and distilled water. according to tafel and cyclic polarization c...

Corrosion is the degradation or deterioration of metal components due to a reaction with the environment. Chromate conversion coating is applied to passivate metallic surface to slow down (and prevent to some extent) corrosion process. Chromate conversion process uses chromium compounds including hexavalent chromium, which is toxic, carcinogenic and hazardous to human health and environment. He...

A smart hybrid conversion coating has been developed. Modifications of coating solutions with poly-hydroxyl organic materials to reduce the usual mud cracking pattern characteristics of chromate conversion coatings (CCCs) and improve its ability to release inhibitors to corroding sites have been achieved. The smart functionalised chromate conversion coating (SFCCC), developed on aluminium subst...

The surface characteristics of an aluminium alloy treated with a commercial chromate pretreatment have been studied by SAM, EDX and XPS. XPS indicates that the chromium is present in the conversion coating as both Cr(III) and Cr(VI) species, and that other components are present at the conversion coating surface, some in a reduced form. The deposition of the chromate layer is compromised by the...

DISCLAIMER This report, prepared in cooperation with the University of Rhode Island Transportation Center, does not constitute a standard, specification, or regulation. The contents of this report reflect the views of the author(s) who is (are) responsible for the facts and the accuracy of the data presented herein. This document is disseminated under the sponsorship of the Department of Transp...

The European Union has banned chromium(VI) compounds in electrical and electronic equipment (EEE), such as chromate conversion coating films. Chromium(III) compounds are not banned. Using Raman spectroscopy without any preparation, we distinguished chromium(VI) oxide from chromium(III) oxide and chromium(III) hydroxide in chromate conversion coating films. Raman bands of chromium(VI) oxide were...

Abstract A novel hybrid sol–gel coating has recently been introduced as an alternative to high toxic chromate-based corrosion protection systems. In this paper, we propose a multiscale computational model to estimate the amount and time scale of inhibitor release of the active corrosion protection coating. Moreover, we study the release rate under the influence of parameters such as porosity an...

Protective coatings have been deposited on electrogalvanized steel by immersion in solutions containing 2-Butyne-1.4-diol propoxylate (C7H11O3), cerium nitrate, sodium nitrate and sodium sulphate for different immersion periods. The surface morphology and chemical composition of the coatings formed on the electrogalvanized steel were studied using field emission gun scanning electron microscopy...

This study investigates the formation of a chromate conversion coating at Al-Cu-Fe-Mn intermetallic sites of an Al2219 alloy and the corrosion initiation at these sites in a 3.5 % NaCl solution, using SEM, AES and EDX. Changes in the surface chemistry were monitored after progressive exposures to the solution up to 42 hours. The coating was found to be thinner and more defective on the intermet...

For commercial applications, specially formulated conversion coating treatments based on chromates and phosphates have been used extensively to prevent rapid Zn dissolution in aerospace, food processing and automobile industries. Chromate coatings are favored due to their barrier and corrosion resistance properties. Chromium deposition is obtained from hexavalent Cr salt baths, which are subjec...