Glass-coated wire
Glass-coated wire is a very fine wire with a metal core wrapped in a glass sheath. It was invented in 1924 by G. F. Taylor and later turned into a production process by Ulitovski. This method can make metal filaments only a few micrometres across.
In the Taylor-Ulitovski process, the metal is inside a glass tube (usually borosilicate). The tube end is heated until the glass softens, allowing the metal to be drawn into a thin glass cap around the metal core. Later versions added continuous feeding, so long wires can be made. The process requires careful control: the metal and glass must melt at compatible temperatures, the pulling speed must stay steady, and the wire must cool evenly.
The method works with many metals, such as copper, silver, gold, iron, platinum, and various alloys. Some setups heat the glass and metal separately to handle metals with higher melting points. The very fast cooling can even create amorphous (glassy) metal cores.
The wire’s properties come from its microstructure, which is set by how quickly it is cooled. Magnetic properties depend on the metal and how the wire was processed; iron-rich alloys are common and can be improved by annealing under stress. The glass coating adds thermal stability and corrosion resistance, making the wires useful in sensors, medical devices, and security labels. In LEDs, using copper-coated glass wires helped cut costs by replacing gold, and newer casting-based methods have boosted mass production.
This page was last edited on 3 February 2026, at 01:33 (CET).