Today, the world’s largest watch group Swatch Group announced on the official website that it and the famous high-end luxury watch brand Audemars Piguet jointly launched a new hairspring called ‘Nivachron’. It is said that this hairspring uses alloy raw materials on the basis of ‘titanium’. Before that, not only the Swatch Group itself, but also the hairspring materials used by other Audemars Piguet watch brands around the world were generally nickel-iron based. The new Nivachron balance spring has many advantages. It can significantly reduce the effect of magnetic fields on the operation of the watch and can effectively resist temperature changes. In addition, it has excellent impact resistance. Ultimately, all these advantages can significantly improve the performance of a watch. The key to a clock’s accurate display of time is the ‘period of the pendulum.’ On mechanical watches, a hairspring is the only part that connects the balance wheel. Although magnetically connected watches have appeared in history, they are all concept models and cannot be mass produced. Therefore, it can be said that the hairspring is the second most important part in a mechanical watch. Most of the raw materials used for hairsprings are made of constant elastic alloys. The significant difference from other metal materials is that its elastic modulus remains constant within a certain temperature range or the absolute value is close to zero. The use of constant elastic alloy can greatly reduce the impact of external temperature on the accuracy of the watch. Because the hairspring is the core component of a mechanical watch, a slight change can have a huge impact on accuracy. For example, when the temperature rises, the hairspring’s thermal expansion length becomes longer, and the watch will slow down; when the temperature is lowered, the hairspring’s cold shrinkage length becomes shorter, and the watch will go faster. In addition to the constant elasticity of the hairspring, it must also be antimagnetic, shockproof, have sufficient strength and elasticity, good stability and processability. The hairspring made in the early days is made of low-carbon steel. The hairspring made of this material is sensitive to temperature and magnetic force. The error of this hairspring clock can be several minutes a day. In addition, the carbon steel hairspring has a low elastic coefficient, which also substantially increases the power consumption of the mainspring. Once the watch enters the water, causing the hairspring to rust and corrode, the entire watch is broken. Watchmakers at the time were eager to find materials to solve these problems. In 1846, Vacheron Constantin already tried to use copper hairsprings and balances, but gave up due to insufficient elastic properties and other mechanical properties of copper metals. At that time, the Swiss Institute of Antimagnetic Metals was also established. As a member of the association, Vacheron Constantin made the first timepieces using palladium metal hairsprings. In 1872, Richard Lange, the founder of the watch brand Lange, registered the patents of aluminum alloy parts and balance springs. Even in 1883, E. J. Dent used glass to make hairsprings. Such hairsprings were not rusty or magnetic, but had to be abandoned because of their high cost and fragility. In 1885, Vacheron Constantin manufactured a timepiece with a balance wheel, a balance spring, an escapement splint, and a gear made of palladium alloy. The escapement fork was made of copper and used a gold escapement. In addition, one of Vacheron Constantin’s many awards at the Geneva Observatory is the use of gold balances and hairsprings provided by the Geneva Gold Processing Factory. Obviously, gold, palladium, glass, and aluminum are not suitable for large-scale production as hairspring materials. At that time, most ordinary timepieces still used traditional low-carbon steel hairsprings, and used the ‘dual alloy temperature difference automatic compensation balance wheel’ to adjust the error caused by the effective length of the hairspring caused by the temperature difference. This type of balance wheel usually has a yellow outer ring. The copper material and the inner ring are made of steel. When the temperature changes due to thermal expansion and contraction, the error caused by the temperature is automatically adjusted by using the physical characteristics of the outer ring metal expansion coefficient greater than the inner ring. As the temperature of ordinary pure metals increases, the bonding force between atoms will gradually decrease, and the constant elasticity of the hairspring made from it will change. The focus of research on constant elastic metals lies in alloys, but there have been no significant results. Until the appearance of French physicist Charles Edouard Guillaume, who was born in Switzerland, he found through a large number of studies that the iron-nickel alloy containing 36% nickel is particularly sensitive to temperature and does not expand significantly with temperature. This is extremely important for isochronous balance springs based on length. He developed the Invar nickel-iron alloy in 1896, named after the abbreviation of ‘invariable’, which means ‘unchangable’. Later, at the request of Paul Perret, a professor of history and nature at the University of Geneva who was also a watchmaker, he began to study the constant elasticity of nickel-iron alloys. In 1904 he discovered that adding chromium to iron-nickel alloys could significantly improve the performance of finished hairsprings. When chromium is added to an iron-nickel alloy, when the chromium content reaches 12% and the nickel content reaches 36%, the absolute value of the thermal expansion coefficient of the alloy approaches zero and the coefficient change is particularly gentle in the room temperature range. Under the guidance of Guillaume, P. Chevenard perfected the formula, made Elinvar, and finally finalized the production. Guillaume invented the Inver Invar Invariant Alloy, because Guillaume won the Nobel Prize in Physics in 1920 for this cross-generational research, which is currently the only achievement from the field of watchmaking that won the Nobel Prize. Because Guillaume was supported by Imphy Alloys, a French professional alloy manufacturer, as a co-inventor of Invar. Yin Fei Company first produced the Elinvar alloy and launched it as a commodity with 1920. It took almost 10 years in the market. The Elinvar alloy replaced nearly 300 years of carbon steel. By 1933, R.Straumann perfected the formulation of the Elinvar alloy in the German vacuum smelting company and made a new Nivarox alloy, which was the origin of Nivarox SA. In 1984, Nivarox SA merged with Fabriques d’Assortiments Réunis (FAR), a Swiss watch parts processor, and changed its name to Nivarox-FAR. Nivarox-FAR is a leader in the manufacture of swivel and escapement parts in Switzerland. Nivarox-FAR was acquired by Swatch Group in 1985. Due to the monopoly of technology and the strong support of Swatch Group, Nivarox-FAR completely occupied the world hairspring market. Even Swatch Group competitors LVMH Group and Richemont Group have had to use Nivarox-FAR products. Nivarox-FAR can be said to be a hidden crocodile in the world’s watch manufacturing industry. The degree of market monopoly is better than ‘ETA movement’. The improvement of watchmaking skills is endless. Nivarox alloys are good, but not the best. At the same time, Hayek held his opponent’s neck tightly through Nivarox-FAR. Some of these brands saw the crisis and generated a little sense of worry, such as Rolex, Athens, and Patek Philippe began to find another way. In the last century, Patek Philippe, Rolex, Swatch Group, and Athens jointly funded the development of a non-metallic material, silicon, with the Swiss Electronics and Microtechnology Corporation (CSEM), a subsidiary of the Neuchate I University of Neuchatel, Switzerland. In addition to constant elasticity, the hairspring made of silicon material is magnetically and shockproof, has sufficient strength and elasticity, good stability and processability. It can be said that ‘silicon’ is the most cross-era material innovation in the watch industry for centuries. In the days that followed, silicon was used not only for the production of hairsprings, but also for the production of core components such as pallets, escapement wheels and balance wheels. However, although the silicon material has unparalleled advantages, it has a disadvantage that it is more fragile than the original alloy as a non-metal material. To put it plainly, silicon components are ‘partial students’. Some disciplines have outstanding results, and some disciplines have obvious shortcomings. Patek Philippe was the first watchmaker to participate in the development of silicon materials. In 2006, Patek Philippe first used a silicon escapement on the mass production model Ref. 5250. Because it was a ‘new material’ at that time, the actual stability of wearing was unknown, so PP promised a five-year warranty with great pride. And also the first Rolex to participate in the research and development is also very cautious, Rolex first used a small size Cal. 2236 movement silicon springs, equipped with smaller demand for female watches. This approach is generally considered to leave enough buffer time for themselves. If silicon is used on the best-selling men’s watches, once an error occurs, it will undoubtedly be a huge blow to the brand image. After more than a decade of actual testing by dozens of brands and millions of consumers, the problems reflected by silicon materials are not as many and horrible as everyone believes. Although silicon is more fragile than traditional metal materials, as long as it is used reasonably, the probability of its damage is extremely low, so low that there is no need to worry. The short board of silicon material parts is now mainly in the later maintenance and repair, because it is integrally formed, and cannot be stitched and repaired later. Once damaged, it can only be replaced after the official after-sales service, and it is difficult to obtain matching parts in third-party agencies. Watches using silicon parts have higher requirements for later maintenance, which can be officially met. But for watch brands, it is impossible for third-party watch repair personnel to avoid it, and it is impossible for officials to open after-sales service centers all over the world. Therefore, everyone is also looking for the balance point of the hairspring production material, which must be ‘easy to use’ and ‘stable’ and can be popularized. For example, Rolex now commonly uses a metal hairspring commonly known as ‘blue niobium’. In 2000, Rolex successfully developed an innovative hairspring and obtained a patent, which is officially called Parachrom hairspring. Its alloy material is composed of niobium niobium, zirconium metal, etc. The early Parachrom hairspring is silver-white. In 2005, Rolex also adopted a new patented technology to improve the surface of Parachrom hairsprings, further improve the long-term stability of the hairspring, and give this hairspring unique blue characteristics. Parachrom hairspring was first used in Daytona’s 4130 movement in 2000, and is gradually equipped in all oyster series men’s watch movements. According to the wording currently introduced by Swatch Group on its official website, it can be clearly seen that the new hairspring ‘Nivachron’ does not have a silicon hairspring in terms of anti-magnetic, constant elasticity and shock resistance, but is superior to ordinary Nivarox hairsprings. In other words, ‘Nivachron’ is the balance between silicon hairspring and Nivarox hairspring, which is both ‘easy to use’ and ‘stable’. Finding the most suitable one among thousands of alloy formulas is not only costly, but also time consuming. Today, the Swatch Group and the watch brand Audemars Piguet announced high-profilely that they are definitely not playing. The introduction of the ‘Nivachron’ balance spring with more balanced performance may lead to the deprecation of the ‘Partial Student’ silicon balance spring.