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Tin whiskers were noticed and documented in the vacuum tube era of electronics early in the 20th century in equipment that used pure, or almost pure, tin solder in their production. It was noticed that small metal hairs or tendrils grew between metal solder pads, causing short circuits. Metal whiskers form in the presence of compressive stress.
Whiskers are used in some composites, but large-scale fabrication of defect-free whiskers is very difficult. Prior to the discovery of carbon nanotubes , single-crystal whiskers had the highest tensile strength of any materials known, and were featured regularly in science fiction as materials for fabrication of space elevators , arcologies ...
Schematic of field desorption ionization with emitter at left and mass spectrometer at right. Field desorption (FD) is a method of ion formation used in mass spectrometry (MS) in which a high-potential electric field is applied to an emitter with a sharp surface, such as a razor blade, or more commonly, a filament from which tiny "whiskers" have formed.
Metal whiskers differ from metallic dendrites in several respects. Dendrites are fern -shaped like the branches of a tree, and grow across the surface of the metal. In contrast, whiskers are fibrous and project at a right angle to the surface of growth, or substrate.
The mechanisms for catalyst-free growth of nanowires (or whiskers) were known from 1950s. [18] The simplest methods to obtain metal oxide nanowires use ordinary heating of the metals, e.g. metal wire heated with battery, by Joule heating in air [19] can be easily done at home.
The explanation was motivated by the absence of axial screw dislocations in the whiskers (which in themselves are a growth mechanism), the requirement of the gold droplet for growth, and the presence of the droplet at the tip of the whisker during the entire growth process.
Tin whiskers are elongated or needle-like structures of pure tin that grow from pure tin and tin alloy surfaces. Toyota's APPS were found to use tin finishes. These tin finishes can produce conductive tin whiskers capable of creating unintended electrical failures such as short circuits.
It consisted of a pea-size piece of crystalline mineral in a metal holder, with its surface touched by a fine metal wire or needle (the "cat whisker"). [2] [4] [20] [23] The contact between the tip of the wire and the surface of the crystal formed a crude unstable point-contact metal–semiconductor junction, forming a Schottky barrier diode.