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

Abstract

In the present work, cysteine and allyl alcohol were added to citrate baths as additives to Cu-Zn coatings on steel substrates. In order to verify the effects of the deposition parameters (current density, mechanical stirring speed, and additives) on the coating composition, electrochemical behavior, morphology, and microstructure properties of Cu-Zn coatings, the electrodeposition of the alloy was carried out using an experimental composite design 2 3 , in which these parameters were considered the entry variables and the measured properties were the response variables. The confidence level was 95% and the results were shown as response surface diagrams. It was possible to verify that the current density affected the zinc content in the coating, while the coating produced from cysteine-contained bath presented the worse anticorrosive performance. In a general way, it was possible to observe that the studied parameters affected the morphology, grain size, and the electrochemical behavior of these coatings, although only a few response variables were statistically influenced by them.

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

“…However, when AA is present in the bath, the j and t parameters have decreased simultaneously in order to increase the R p . Noteworthy, although high values of S can keep the particles suspended, low values of t may decrease the stabilization of the particles 21 , while low values of j favor copper deposition in a bath containing AA 41 . As a leveling agent used for metallic coatings, AA decreases the internal stress of the coating/substrate system, which generally favors the production of coatings presenting small grain size, without defects, pores or cracks 51,52 .…”

“…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] . The microstructure of the composite coatings depends on both the metallic matrix and the second phase material.…”

“…The microstructure of the composite coatings depends on both the metallic matrix and the second phase material. However, these coatings often present rough surfaces and defects, and additives can be added to the electrodeposition bath to improve morphological and anticorrosive properties, as it is usually used for metallic coatings [41][42][43] . These additives are organic compounds, whose functions are to refine the grains obtained in the electrodeposition process, reproduce the brightness of the original metal and promote the formation of layers without defects or cracks 42,43 .…”

“…Allyl alcohol is a low molecular weight alcohol, reported as a brightening agent and tension reliever. This compound is commonly used as additive in the production of Cu coatings and Cu-Zn alloy 41,42 and has never been used as a levelling agent in electrodeposition of composite coatings. A 2³ central composite design was used to verify the effects of three deposition parameters (current density, j, stirring speed of the rotating disc electrode during the co-deposition process, S, and the stirring time before the co-deposition process starts, t) on the studied deposition variables (polarization resistance, R p and the charge transfer resistance, R ct ).…”

EFEITO DA GELATINA COMO ADITIVO PARA ELETRODEPOSIÇÃO DE LIGAS Zn-Co A PARTIR DE CORRENTE PULSADA SIMPLES

“…Aditivos, tais como a gelatina, benzotriazol, cisteína, álcool alílico, entre outros, também são geralmente adicionados ao banho de eletrodeposição, pois promovem a formação de grãos mais refinados e estruturas mais regulares. Muitos deles também contribuem para aumentar a proteção anticorrosiva do depósito (Karahan et al, 2008;Garcia et al, 2013). Garcia et al, (2014) mostraram que revestimentos de liga Zn-Co com maiores teores de cobalto, grãos refinados e uniformes, foram produzidos por corrente pulsada simples, a partir de banhos contendo citrato de sódio.…”