@article{
author = "Tomić, Milorad V. and Pavlović, Lj.J. and Pavlović, Miomir and Mićić, Vladan and Đukić, B.",
year = "2011",
abstract = "This paper analyzes the catalytic effect of sulphuric acid on current efficiency, the coating thickness and the rate of deposition of electrochemical chromium coatings. According to the properties of chrome, there are three types of chrome coatings: decorative, hard and porous. The quantitative composition of baths and working conditions are the factors which determine which type of a coating will be obtained. The cathodes are made of copper electrolitical plates (99.99%), which are submitted to mechanical smoothing and chemical preparation. Electrochemical chromium coatings were deposited galvanostaticaly from bath I (250 g/dm3 CrO3 + 2.0 g/dm3 H2SO4), are then deposited on the cathodes prepared in this way, also from bath II (250 g/dm3 CrO3 + 2.5 g/dm3 H2SO4), and from bath III (250 g/dm3 CrO3 + 3.0 g/dm3 H2SO4), at current densities of 10 A/dm2, 15 A/dm2 and 30 A/dm2. Deposition was performed for 5, 10 and 15 minutes intervals in all three baths and for all three current densities. The difference in samples mass before and after electrochemical deposition was measured on the analytical scale. Cathodic current efficiency, the coating thickness and deposition rate increase with the increase of acid concentration, current density and deposition time. The average deposition rates are approximately the same for baths II and III, for the same deposition time, at the same current densities. This shows that the increase of the concentration of sulphuric acid above 2.5 g/dm3 is not justifiable. The ratio of these parametres, according to the quantity of the sulphuric acid used is the best for bath II, which makes deposition of electrochemical chrome coatings from this bath most profitable, from the aspect of current efficiency, deposition rate, coatings quality and chemicals consumption of bath., Ispitivan je katalitički uticaj sumporne kiseline na iskorišćenje struje, debljinu i brzinu taloženja prevlaka hroma dobijenih elektrohemijskim putem. Zahvaljujući osobinama hroma razlikuju se tri vrste prevlaka: dekorativne, tvrde i porozne. Kvantitativni sastav kupatila i radni uslovi su faktori koji određuju koji tip prevlaka će biti dobijen. Katode su bile od tehničkog bakra nepoznatog sastava, koje su mehanički glačane pa zatim hemijski pripremljene. Za elektrohemijsko taloženje prevlaka hroma, koje su taložene galvanostatski, ispitivana su tri elektrolita čiji se kvantitativni sastav razlikuje u koncentraciji sumporne kiseline, dok je koncentracija CrO3 bila ista u sva tri kupatila i to: kupatilo I (250 g/dm3 CrO3 + 2.0 g/dm3 H2SO4), zatim kupatilo II (250 g/dm3 CrO3 + 2.5 g/dm3 H2SO4), i na kraju kupatilo III (250 g/dm3 CrO3 + 3.0 g/dm3 H2SO4), pri gustinama struje 10 A/dm2, 15 A/dm2 i 30 A/dm2. Katodno iskorišćenje struje, debljina prevlaka i brzina taloženja se povećava sa povećanjem koncentracije sumporne kiseline, gustine struje taloženja i vremena taloženja. Srednje brzine taloženja prevlaka hroma su približno iste za kupatila II i III, pri istim vremenima taloženja i pri istim gustinama struje. S tim u vezi, povećanje koncentracije sumporne kiseline iznad 2,5 g/dm3 nije opravdano. Odnos ovih parametara, prema koncentraciji sumporne kiseline, je najbolji za kupatiko II, koje daje optimalne prevlake hroma dobijene elektrohemijskim putem, u pogledu iskorišćenja struje, brzine taloženja, kvalitata prevlake i hemijskog sastava kupatila.",
publisher = "Belgrade, Serbia : Engineering Society for Corrosion",
journal = "Zaštita materijala",
title = "Catalytic effect of sulphuric acid in the process of deposition of chromium coatings, Katalitički uticaj sumporne kiseline u procesu taloženja prevlaka hroma",
volume = "52",
number = "3",
pages = "181-188",
url = "https://hdl.handle.net/21.15107/rcub_cer_871"
}
