Investigation of Whisker Growth from Alkaline Non-cyanide Zinc Electrodeposits

Abstract

Electroplated zinc finishes have been widely used in the packaging of electronic products for many years as a result of their excellent corrosion resistance and relatively low cost. However, the spontaneous formation of whiskers on zinc electroplated components, which are capable of resulting in electrical shorting or other damaging effects, can be highly problematic for the reliability of long-life electrical and electronic equipment. This work investigated the mechanism for whisker growth from zinc electrodeposited mild steel substrates. The incubation time for whisker growth from the surface of nodules on the surface of the electrodeposit was considerably reduced compared with that from the planar deposit surface. Recrystallisation of the as-deposited columnar structure was observed at the whisker root. This result is consistent with some recent whisker growth models based on recrystallisation. There was no evidence of iron-zinc (Fe-Zn) intermetallic formation at the iron/zinc (Fe/Zn) interface or within the zinc coating beneath the whiskers.

Crystal Growth and High-Pressure Effects of Bi-Based Superconducting Whiskers

“…For over 70 years, whisker materials consisting of needle-like single crystals have attracted attention as unwanted spontaneous growth on metal electrodes in electronic devices. − On the other hand, whisker crystals could provide insights into the intrinsic physics of functional materials because of their nearly perfect crystallinity . The growth mechanism of simple substance whiskers has been studied in the past several decades, − but it has not been understood completely. A key factor for whisker growth in several simple substances is considered to be compressive stress in the precursors. − …”