Inside G&F Châtelain, the ceramics manufacturing facility of Chanel timepieces
he trouble with ceramic isn’t that it’s brittle — its frequent presence in various external watch components today, such as cases, bezels and dial crystals, tells us it isn’t so. Nor is the problem that it’s tremendously hard to produce in complex shapes. Previously, perhaps, this was a concern, but one look around you at the various ceramic timepieces available now will dispel this fallacy. Its limited color range? That’s changing as well, and in any case, it’s not as if any other comparable watchmaking material comes in a rainbow palette. No, the real trouble with ceramic is that — even now, with ceramic watches having been around since the mid-1980s — no one really knows the first thing about ceramic as a material. It doesn’t help that the term encompasses so many completely different definitions. That coffee mug on your desk is ceramic, just as those thermal shields on space shuttles are. You can obtain super-hard drill bits made of ceramic, just as easily as you can find an ultra-expensive fine porcelain dinner service (yes, also ceramic) that you’ll get screamed at by the other half for putting in the dishwasher. You may not see much of a connection between advanced ballistics body armor and that slop that Patrick Swayze and Demi Moore were messing about with in Ghost, but (as you may have guessed by now) they’re both accomplished with ceramic materials. Ceramic can be transparent (sapphire crystal, that is, monocrystalline aluminium oxide, is a great example) or it can be utterly opaque. Its atomic structure can be monocrystalline, or it can be polycrystalline, or it doesn’t have to be crystalline at all, in which case it is fully amorphous, and some — though not all — materials scientists will grimace and state their preference for the term “glass” under such circumstances. Therein lies an entirely new story, which we can explore some other time when immediate somnolence is required. If you cut away all the things that it is not, however, then it becomes relatively straightforward to identify the technical limits of what constitutes a ceramic. A ceramic is a non-metallic, inorganic solid formed by the application of heat and subsequent cooling. Large boules of sapphire crystal, for example, are formed through heating pure powdered alumina and oxygen in a large furnace and allowing it to reform as a single crystal. Zirconium oxide, which is the material used in the vast majority of ceramic watchcases, goes through high-temperature sintering in its crucial final stages to render it a dense, extremely hard solid. One of the most consistently stellar manufacturers of ceramic watches is Chanel, with the popular J12 line of timepieces. Chanel first debuted the J12 watch in 2000 in black ceramic, with a white version joining the collection in 2003. Since 2010, Chanel have also introduced a third color to the black-and-white spectrum of ceramic available for their watches — the metallic gray sheen of the J12 Chromatic. The company that produces the black and white ceramic cases and bracelets for Chanel, G&F Châtelain, was acquired by the former in 1993, a key investment that would allow Chanel to control every aspect of the feature that defined their iconic watch collection. Châtelain is tucked away in the light industrial area of
La Chaux-de-Fonds, counting as its neighbors facilities belonging to other companies such as Greubel Forsey, Patek Philippe, Jaquet Droz, Breitling and Cartier. Inside the sprawling interior of G&F Châtelain, one of Europe’s most sophisticated and experienced manufacture processes of zirconium oxide ceramic takes place. The first step of creating the incredibly high-performance and hardwearing ceramic cases that house the Chanel J12 is to secure the best-quality precursor. This includes raw ceramic powder sourced from Japan and Châtelain’s own in-house expertise in blending the ceramic powder with organic binder in a formula that is exclusive to Chanel. The raw ceramic material, known as feedstock, is then shaped using injection molding techniques into what is known as green forms, and it is the organic binder that allows the raw ceramic powder to be thus plastically shaped. These stages have to be extremely carefully regulated, as the integrity of the final ceramic product depends largely upon the green ceramic form being completely homogenous in terms of material composition. The green forms undergo machining to get them more or less into their final shapes. This is how ceramic cases are now able to hold such complex forms, whereas in the past the method of milling cases out of solid ceramic blanks was understandably labor- and time intensive, leading to simpler case geometries. Once the machining is done, the green forms undergo debinding, which leaches the organic material out of the forms and leaves only the ceramic in a loose, porous matrix. At Châtelain, a proprietary binder formula is used so that harmful chemical processes can be avoided. In this instance, the debinding is accomplished only with water and heat. Part of the binder is leached away in a temperature-controlled water bath, and the rest is eliminated overnight in a 300°C kiln. At this stage, the ceramic forms are curiously fragile, disintegrating and crumbling upon the pressure of a fingernail, rather like classroom chalk. The forms are then sintered in an oven that is set at 1,200°C. This is where the importance of getting the initial feedstock formula exactly right comes to bear. When sintering, the ceramic undergoes densification and molecular bonding, which means the forms shrink. This shrinkage can be calculated very precisely according to the ratios of ceramic powder to binder — typically they are calculated to shrink at a rate of 20–30 percent. These calculations are obviously essential to keeping the final ceramic product within the dimensions required by the watch design. The importance of having a feedstock that is perfectly uniform, will also tell at this precise stage. Unevenly distributed feedstock elements can lead to sections of the green forms being denser than others, which at the sintering stages will create uneven shrinkage. When the ceramic forms emerge from the sintering stages, they are incredibly hard and dense. Grinding and polishing — the latter process taking place in a rotating drum laced with ceramic beads and abrasive liquid containing synthetic diamond — take them into their final stages, and they are ready to be assembled into cases, bracelets or buckles. By the standards of some other companies that have been in the watchmaking business for centuries, the history of timepieces at Chanel may seem relatively short. However, this hasn’t stopped them from producing some truly exceptional pieces, such as this year’s J12 Flying Tourbillon with asymmetrical tourbillon cage. By aligning their best-selling collection — the J12 — with a completely in-house competency such as high-tech ceramics manufacture, Chanel have ensured their ongoing production of quality, contemporary timepieces.
Chanel carefully controls the raw materials that go into creating the incredibly high-performance and hard-wearing ceramic cases of the J12 timepieces The limited- edition J12 Intense Black features 724 baguette- cut high-tech ceramic pieces that...