Corrosion Resistance Of Zn-Sn Alloys Horizontally Directionally Solidified

MIRIAM B. PARRA; CLAUDIA M. MÉNDEZ; CARLOS E. SCHVEZOV; ALICIA E. ARES

San Antonio, TX

Simposio; TMS 2013. 142st ANNUAL MEETING & EXHIBITION-Materials Processing Fundamentals.; 2013

TMS

The aim of this study is to evaluate the effects of the microstructural arrangement of Zn-Sn alloys horizontally directionally solidified on its resultant corrosion behavior. In this context, a water-cooled horizontal unidirectional solidification system was used to obtain alloy samples. Electrochemical impedance spectroscopy and potentiodynamic polarization curves were used to analyze the corrosion resistance in a 3% NaCl solution at 25 °C. Microscopic observation of the samples denote a higher susceptibility to pitting corrosion by the Sn, with lots of deep and localized pitting in the order of 10 microns. On the other hand, samples of Zn-Sn alloys and pure Zn showed a more generalized corrosion, with largest number of pinholes and with a depth of 4-5 microns approximately. Also, it was found that the presence of Sn in the analyzed samples affects the corrosion potential, becoming the alloys nobler respect to pure Zn.