Response surface analysis to evaluate the influence of deposition parameters on the electrodeposition of Cu–Co alloys in citrate medium

Abstract

Copper-cobalt alloy coatings were deposited on mild steel substrates using sodium citrate electrolytes at room temperature and under direct current. A set of cathodic polarization curves was plotted by varying the mechanical stirring speed of the solution (0-400 rpm), using a range of current densities during the electrodeposition experiments. Factorial design was used to verify the influence of these deposition parameters on the cathodic efficiency, the copper and cobalt content in the coating, the corrosion current density of the coating/substrate system, and the efficiency of the coating in protecting the substrate. The electroplating experiments showed that, with the studied bath composition, high stirring speed and low current density lead to greater cathodic current efficiency and copper-rich coatings. On the other hand, high current density and low stirring speed yields coatings with high cobalt content and a lower cathodic efficiency. Our results show that the studied parameters affect the corrosion current density and the coating efficiency of the coating/ substrate system in opposite ways. The best results were obtained increasing the current density and decreasing the mechanical stirring speed. Additionally, three samples were produced in selected deposition conditions. The coatings morphologies were compact, and their grain sizes seemed to enlarge with increasing stirring speed and decreasing current density.

Statistic evaluation of cysteine and allyl alcohol as additives for Cu-Zn coatings from citrate baths

“…In all cases, substrate depolarization was observed as S increased. Strong polarization had been noted for the deposition of copper and copper alloys in a citrate electrolyte without stirring because of the effects of blocking species (mainly Cu-citrate complexes) 14,[18][19][20] . This influence usually decreased at higher values of S 14,15,18 due to the increase in the mass transport.…”

Experimental Design and Response Surface Analysis as Available Tools for Statistical Modeling and Optimization of Electrodeposition Processes

“…For screening, primarily two-level full factorial (Santana et al, 2006;2007a;2007b;Souza e Silva et al, 2006) and fractional factorial designs (Wery et al, 1999;Hu & Bay, 2001a;2001b;Tsay & Hu, 2002;Hu et al, 2003;Bai & Hu, 2005;Hu et al, 2006;Dubent et al, 2007) have been applied. For the actual optimization of important factors, response surface designs, such as central composite (San Martín et al, 1998;Hu & Bay, 2001a;2001b;Tsay & Hu, 2002;Hu et al, 2003;Bai & Hu, 2005;Hu et al, 2006;Silva et al, 2008;Musa et al, 2008;Poroch-Seritana et al, 2011), Box-Behnken (Morawej et al, 2006), and Doehlert (Chalumeau et al, 2004;, have been used.…”

“…Experimental design has been applied to study the influence of several parameters on the electroplating of Cu-Zn alloy in cyanide medium (Musa et al, 2008), and response surface modeling and optimization has been used by the Senna group to study the influence of deposition parameters on the electrodeposition of both Cu-Zn and Cu-Co alloys from in citrate medium (Ferreira et al, 2007;Silva et al, 2008). Cembero & Busquets-Mataix (2009) have also used experimental design to study the most important parameters in the production of ZnO crystals by electrodeposition.…”

“…For example, electrodeposited Cu is the material of choice for the interconnects in ultra-large-scale integrated (ULSI) circuits, and electrodeposited soft magnetic alloys are an important component of magnetic recording heads (Schwarzacher, 2004;Yoshida et al, 2009). In fact, the deposition of alloy coatings is one of the most rapidly expanding topics in the current literature (Oriňáková et al, 2006;Santana et al, 2006Dubent, 2007;Ferreira et al, 2007;Silva et al, 2008;Brankovic et al, 2009;Gupta & Podlaha, 2010, Düzgün et al, 2010. Compared to the electrodeposition of a single metal, alloy coatings show better properties because their chemical composition can be varied to the required function.…”

Electrodeposition of Composite Coatings of Cu/AlO(OH) Using Allyl Alcohol as an Additive

“…They also provide the necessary statistical inference for a better process efficiency 34,35 . In addition, it is possible to create new coating systems that can fulfill different industrial needs 31,36,37 . Nowadays, several reports can be found in the literature concerning the use of these methodologies to enhance the quality of electrodeposition baths or to achieve realistic optimized conditions 30,[32][33][34][36][37][38][39][40][41] .…”