Microscopy and Microanalysis | 2021
Microanalysis of Cd Whiskers on Cd Plated Long-Term Used Hardware
Abstract
Cadmium whiskers were recently observed on field-return hardware at Sandia during a fastener failure analysis study unrelated to whisker growth. In this study, approximately 200 cadmium plated cap screws and 400 cadmium plated nuts with varying service lifetimes, were examined and cadmium whisker growth was ubiquitous. Previously published characterization work on cadmium whiskers contained smaller samples of whiskers and relied on whiskers grown from the vapor phase. These studies were also conducted prior to the advent of modern EBSD technology [1,2]. Here we report on the microanalysis of cadmium whisker growth that occurred organically on cadmium plated hardware. They demonstrated a preferred growth direction of < –1 2 –1 0 > , but begged the questionis this direction also preferred by whiskers grown from solid state plating? Why is direction preferred? What other growth directions are possible? These questions were addressed by characterizing 50 cadmium whiskers with scanning electron microscopy (SEM) and electron backscatter diffraction (EBSD).