Richard Mille has long been at the forefront of introducing new materials into watchmaking, particularly those used in the world of Formula One auto racing. At this year’s SIHH, the brand introduced yet another first in that area: the new RM 011 Flyback Chronograph, the first watch with a case made of brown silicon nitride.
The new RM 011 is equipped with Richard Mille’s automatic caliber RMAC1, now updated to include a flyback chronograph mechanism. In addition to a tourbillon and an annual calendar function, the movement also includes a “variable geometry rotor,” a device exclusive to Richard Mille, which optimizes the winding of the barrel by adapting it to the user’s activities — i.e., different settings based on one’s level of physical activity that help to avoid overwinding the mainspring.
The watch gets its distinctive, metallic brown color from the innovative new case material, brown silicon nitride, which is exceptionally hard (1,500 Vickers) and displays high resistance not only to wear and corrosion, but also to severe temperature variations. It is also very lightweight, which is why it is used in the automobile industry to make parts such as valves and turbocharger rotors.
The manufacturing process for silicon nitride minimizes the porosity in the raw material. The powder is formed in an isostatic press, which applies pressure of about 2,000 bars. The blank obtained from the pressing is then heated to 1,500°C; extreme care must be taken, as a deviation of 10°C from this temperature can quickly alter the material’s physical characteristics. After 12 hours at extreme temperatures, the volume of a part will have diminished by more than 20 percent.
The silicon nitride parts used for the bezel and caseback of the RM 011 are machined with diamond tools that are capable of performing the complex operations required to create the case’s tonneau shape. The finished parts are embellished with satin-brushing and microblasting. Satin-brushing is also used on the case middle, crown and chronograph push-pieces, which are constructed of 18k rose gold. The push-piece guards are in polished grade 5 titanium.
The RM 011 Brown Silicon Nitride is available from Richard Mille boutiques and the brand’s retailers. (The image below can be enlarged with a click.)
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