Wollaston wire

A Wollaston wire is a very fine wire of platinum with a diameter less than 0.01 mm. The wire is named after the British physicist William Hyde Wollaston, who engaged in the early 19th century with the production of very fine wires. Wollaston wires are among the thinnest wires.

The original method of preparation went through several process steps. The platinum wire is first drawn to a diameter of about 0.08 mm, thinner gauges are not directly accessible by wire drawing, as the material breaks through. The platinum wire is then galvanically coated with an approximately 2.5 mm thick silver layer. The composite wire thus obtained is repeatedly drawn in a row until the diameter is a minimum of about 0.05 mm. Of the silver coating is then removed in an acid bath of nitric acid, whereby the final platinum wire has a diameter of about 1.5 microns.

Applications of Wollaston wires were in the range of crystal detectors in the detector receivers, radios from the early days of the Hörrundfunks. Here, the Wollaston wire served as the contact wire to the crystal to demodulate the broadcast signal. Later and until now usual applications of the platinum wire in the range of temperature measurement and in the high frequency metrology.