Growth of a Large Number of Iron Whiskers by the Reduction of Halides

Abstract
A great number of iron whiskers have been grown by the reduction of iron halides with addition of a small amount of carbon black. The addition of carbon black to the halides was effective for growing a large number of iron whiskers in the atmosphere of hydrogen and a charcoal-air system. Some of the whiskers had a foreign particle at the tip, and their mechanical property and morphology were similar to that of the normal whisker. The whiskers of another type were fine and often grew outward from a carbon black particle in a bundle form. Most of the halide in the original charge was reduced to iron whiskers. Some properties of the whiskers and the growth mechanism were discussed. Experimental results indicate that a chemical reaction at a growth step is required and carbon black added provides the growth site as foreign particles.