Effects of Ethoxylated α-Naphtholsulfonic Acid on Tin Electroplating at Iron Electrodes

Abstract

Effects of ethoxylated ␣-naphtholsulfonic acid ͑ENSA͒ on the initial stages of tin plating have been studied on iron electrodes in an acidic stannous sulfate solution containing phenolsulfonic acid as a supporting electrolyte using potentiodynamic polarization, electrochemical quartz crystal microbalance ͑EQCM͒, scanning probe microscopy ͑SPM͒, and electrochemical impedance spectroscopy techniques. The smallest exchange current density and a larger transfer coefficient are observed at a typical ENSA concentration used in industrial plating baths, i.e., 0.013 M. The SPM imaging and EQCM measurements show that ENSA molecules form a compact structure by interacting with neighboring molecules at the iron surface, which controls the mass transport for Sn͑II͒ reduction. The EQCM studies indicate that the ENSA molecules remain stably adsorbed on the electrode surface at considerably high overpotentials. The ENSA molecules present in both the tin layers and the solution are found to slow the hydrogen evolution reaction at, as well as the corrosion process of, the tin-plated electrode, acting as an anticorrosion agent in commercial tin plating baths.

A review of developments in the electrodeposition of tin

“…Table 2 shows examples of recent bath formulations. [7][8][9][10][11][12][13][14][15][16] Several recent investigations from our laboratory have been based on acidic electrolytes. Such baths contain sulphuric acid (molar mass: 98.1 g mol -1 ), methanesulfonic acid (molar mass:…”

“…The presence of the naphtholsulfonic acid also slowed down the hydrogen evolution reaction and reduced the impact of tin dissolution. 11 The effect of gelatin on tin deposition from sulphuric acid has been studied in some detail. The potential for hydrogen evolution was shifted to more negative values; approximately 0.3 V in the presence of 2 g dm 3 gelatin and the limiting current density was lowered.…”

The influence of a perfluorinated cationic surfactant on the electrodeposition of tin from a methanesulfonic acid bath

“…Such additives can be non-ionic, anionic or cationic [4,5]. Table 1 shows recent examples of electrolyte conditions used to electrodeposit tin [6][7][8][9][10][11][12][13][14][15].…”

Effect of Organic Additives on Electrodeposition of Tin From Acid Sulfate Solution

“…Among them are grain refiners (e.g., aldehydes, thiourea, PEG decyl glucoside, gelatin, peptone) [4][5][6][7], brighteners (e.g., Triton X-100, formaldehyde) [5,8,9], levelling additives (e.g., sesame oil, aromatic carbonyl compounds) [10][11][12], and complexing compounds (e.g., citrate, gluconate, tartrate) [13][14][15][16] were examined. The influence of bath constituents on the course of the early stages of tin electrodeposition and the kinetics of Sn(II) ion reduction was also discussed in some papers [15][16][17][18][19][20][21], as it shows a great influence on the further growth of the metal layer. In turn, Sharma et al [22] showed that the morphology of tin deposits can also be modified by the proper selection of current density, duty cycle, and frequency during pulsed current electrodeposition.…”