Electroplating of Copper on Low Carbon Steel from Alkaline Citrate Complex Baths

Abstract

The use of alkaline electroplating baths is the essential requirement to deposit Cu directly onto steels because of non-adherent Cu formation by replacement reaction between Cu 2 + and Fe in acidic solution. For the development of such an electroplating bath, complexing agents to form soluble Cu complex in alkaline pH is necessary at first. Secondary, the soluble Cu complex must be reduced electrochemically. Cyanide-based baths meet these requirements, but the bath is toxic. In this study, the survey of complexing agents revealed that citric and tartaric acids form soluble copper complex solutions in alkaline pH, and electroplating is possible. The cathodic current density range to obtain smooth and adhesive electroplating with citrate complexed bath was extensive than that with a tartrate bath. It was found that 0.1 mol dm − 3 CuSO 4-0.5 mol dm − 3 citric acid baths with pH of 9-11 are optimum to obtain adhesive and uniform Cu layer. Copper electroplating with an acidic CuSO 4-H 2 SO 4 bath was possible on 1 μm Cu layer with the alkaline citrate bath. Because the plating rate is high with the acidic bath, the multilayer Cu electroplating from the citrate bath and then an acidic sulfate bath gives a reasonable way for Cu coating onto steels. Elongation test of the steel sheet electroplated with the multilayer Cu showed that detachment of the Cu layer was limited in the vicinity of the broken part of the sheet. It is concluded that the toxic cyanide Cu plating bath can be replaced with a citrate bath.

Effects of Electrolyte on Laser-Induced Periodic Surface Structures with Picosecond Laser Pulses

“…As liquids, we prepared water, 5 and 10 wt% NaCl solutions, 5 and 10 wt% NaNO 3 solutions, 5 and 10 wt% Cu(NO 3 ) 2 solutions and 5 and 10 wt% CuSO 4 solutions. NaCl solution and NaNO 3 solution are often used for ECM [ 23 , 24 , 36 , 37 ], and Cu(NO 3 ) 2 solution and CuSO 4 solution are used for electrochemical deposition of copper [ 32 , 33 , 34 , 35 ].…”

“…The objectives of this study were to verify the effects of electrolytes on the fabrication of LIPSSs since a few studies have reported that LIPSS geometry depends on the irradiation environment [ 31 ]. We also aimed to spheroidize copper since ECM can coat with copper using copper nitrate (Cu(NO 3 ) 2 ) solution and copper sulfate (CuSO 4 ) solution [ 32 , 33 , 34 , 35 ] since a long-pulsed laser or a continuous laser have been mainly used for laser enhanced electroless plating and the effects of an SPL on metal deposition with the fabrication of LIPSSs have never been studied. Experiments of laser irradiation with 1064 nm and 20 ps laser pulses at 0.04–1.0 J/cm 2 on the workpiece of 304 stainless steel under air, water, sodium chloride (NaCl) solution, sodium nitrate (NaNO 3 ) solution, copper nitrate (Cu(NO 3 ) 2 ) solution and copper sulfate (CuSO 4 ) solution, were conducted to fabricate LIPSSs in liquids and to change the surface composition.…”

Toward Preeminent Throwing Power from a Novel Alkaline Copper Electronic Electroplating Bath with Composite Coordination Agents

“…The citrate can not only act as the supporting electrolyte of the plating solution, but also increase the cathodic reduction overpotential of copper ion and refine the grain of copper coating. Saeki et al [19] reported that the grains obtained from the citrate bath were finer and closer to each other than that of acidic sulfate Cu plating bath by SEM images of copper coatings with different thicknesses. Kim and Duquette [20] found that the concentration ratios of [Cu 2 + /Cit 3À ] controlled the morphologies of copper coatings in wafer trenches by AFM image study.…”

Copper Surface Treatment Method with Antibacterial Performance Using “Super-Spread Wetting” Properties

“…However, there are problems associated with the copper coating process. The widely used copper-plating process uses cyanide ions, which can cause serious environmental pollution problems [ 27 , 28 ]. Other methods, such as plasma treatment with oxygen, chemical vapor deposition, and ammonia plasma, require complex equipment and procedures [ 29 , 30 , 31 , 32 ].…”