Silicon for beginners
Gisbert L. Brunner has been writing about watches and chronometry since 1981. He has been attending Baselworld since 1982
For hundreds of years, brass, steel and synthetic ruby have been the stuff of mechanical movements. But there’s been a breath of fresh air on the watch scene ever since 2001.
That was when Ulysse Nardin presented the new dual direct escapement with silicon escape wheels. In its monocrystalline form, the material has the same crystalline structure as a diamond, which means it is very hard – 60% harder than steel – but 70% lighter.
Silicon is anti-magnetic and non-corrosive. Even without complex processing it has an extremely smooth surface which considerably reduces friction. All of which makes lubricant unnecessary. Silicon is also highly elastic but it doesn’t lose its shape, which is why Ulysse Nardin is the first watch-manufacturer in the world to make even hairsprings out of thermally stabilised silicon. The only mistake they made was failing to register a patent.
Early in the 21st century, Patek Philippe, Rolex and the Swatch Group got together with CSEM (The Swiss Center for Electronics and Microtechnology) and the University of Neuchatel’s Institute for Microtechnology to work on silicon.
In 2005, the first components made of Silinvar became available, that is to say made of a silicon which was virtually unaffected by fluctuations in temperature. This is caused by the application of a stabilising oxide coating. Silinvar (invariable silicon) is two thirds lighter than Nivarox, anti-magnetic, non-corrosive and self-adjusts to fluctuations in temperature. At changing temperatures, fixed-length hairsprings produced using the DRIE-process remain equally elastic. While Invar hairsprings already undergo macroscopic changes in shape when confronted with 1000 G, that is to say one thousand times their own weight, Silinvar hairsprings can withstand forces of up to 5000 G. All the little knocks a watch routinely suffers in the day-to-day have no negative impact on accuracy.
Due to cost, patented Silinvar hairsprings have to date only been used in very high-end and, consequently, expensive wristwatches but that is now a thing of the past. In the run up to Baselworld 2017, which will open its doors on March 23, Swatch Group subsidiary Tissot will present the Ballade with the Powermatic 80 calibre.
What is unusual about this very classic-looking newcomer is its silicon hairspring. The watch is available in a number of designs and sizes for both men and women. Before the movement can take pride of place within its case, it has to demonstrate its accuracy in 15 days of COSC (Contrôle Officiel Suisse des Chronomètres) testing. Once fully wound, the rotor guarantees the automatic movement an 80-hour power reserve.
The stainless steel, 39-mm Ballade, which is water-resistant to five bar and features sapphire crystal and a leather strap, will set you back about €900 (+VAT). There are also two-tone designs with a yellow and pink gold PVD coating.