Speaking of ceramics, many people may have such a childhood experience: in the art class, the teacher brought a pile of clay, the children made a lot of mud and finally made a bunch of strange ceramic cups… Perhaps it is the initial impression of many people on ceramics.
However, today, ceramics have got rid of this “old and ugly” label, many high-grade ceramics have become the toon in watchmaking materials, ceramic bezels, ceramic cases, etc. are endless, and with its solid Durable nature and beautiful shape have been loved by people. The most typical example is the water ghost.
The ceramic bezel is one of the killing tricks of the water ghost
Although ceramic materials are so popular, many watchers have only heard of its reputation, but have little knowledge of its principles. Today, we will come to you for science, why can ceramics be used in watchmaking, what advantages and disadvantages does it have, and how we should choose.
Ceramics are inorganic non-metallic materials composed of metallic and non-metallic compounds. This is a conforming material that contains some metal components, but cannot be defined as a metal; the remainder of the mixture consists of complementary non-metallic materials, and when these non-metallic materials are combined, A special material with different properties – ceramic.
Ceramic is the most rigid and hardest material in engineering materials, but because it is too hard, it also gives it a “brittle”. This is the opposite of metal.
To understand the difference between the two, you can imagine this: Metal material is like a bunch of rubber bands tied into a ball, the ball feels very strong, but because the rubber is easy to deform, it is quite elastic when pressed. This metaphor is slightly exaggerated, but it is very consistent with the characteristics of metal materials. The type of metal bond makes the atom move under pressure, so the metal can change shape by hammering.
But ceramics are different. For example, ceramics are like a building block made of interconnected hardwood sticks. This is a more sturdy structure that does not easily deform when stressed. But just because they are “reluctant” and not deformed, they will continue to withstand more and more force until the force is strong enough to destroy the connected sticks, and the whole structure collapses. The ceramics are broken. Come.
To explain with a little scientific explanation, it is because the combination of ionic and covalent bonds in ceramic materials is very strong and swatch, these keys are firmly locked in their own positions, and it is difficult for external forces to separate them. Therefore, the ceramic material can remain strong under great pressure.
However, it should be noted that the “stubborn” of ceramics only appears when dealing with compressive forces. In the face of shear, tension or high-speed impact, the resistance of the ceramic will be seriously reduced. The reason for this involves some material science knowledge. I try to explain it easily: in ceramics, the inherent strength of chemical bonds and the formation of crystals microscopically cause the material to have a direction, the shape of the particles (microcrystals) It’s a bit like a pile of stones, and the direction is random. At the micro-level, this stack will have granular boundaries that are just aligned with each other, creating a continuous granularity boundary where aggregate sliding can occur. It takes a lot of force to slide them, but once they slide, they move away from the complementary grain boundaries and cannot find a new position, causing the material to continue to slip outward and begin to break. A summary of the sentence: the more stubborn, the more painful when broken.
It should be noted that the force required to cause the grain boundary to slip in the ceramic material is very large, so in most cases, the ceramic material is difficult to break or deform. If you want a material that doesn’t respond and has no traces, no matter how strong the pain is, then ceramics is your best choice, and their resistance to deformation is really good. However, if you focus on a small point to “attack” it, the grain boundary will easily slip and the material will break. Just as you knock a stone with a big hammer, it may not be a reaction for a long time; but if you take a pointed slap, you can break the stone twice.
With the help of modern technology, we have been able to artificially control the size, shape and overall distribution of ceramic particles to create ceramic materials with different characteristics. Some ceramic materials can produce and withstand certain plastic deformations (the properties become somewhat similar to metals and can be bent); some ceramic materials can withstand high pressures and shear forces…these different types of ceramics It is used on the case, bezel and other watch parts as needed, making your watch resistant to scratches and abrasions.
The advantages and disadvantages of ceramics are equally obvious. For other materials, once they are formed, they usually do not break completely under the action of force, but bend or restore shape after deformation in an instant; ceramics are different, once the force of the ceramic is too large to deform, Then this deformation is often permanent. For example, when the gem in the movement is damaged, the form is fragmented, and then the debris is scattered everywhere; while the rod or gear inside the movement is damaged, it is often simply bent or broken, far less so “tough” “. This is the reason why the movement material rarely uses ceramics. Except for a few large parts such as splints, other parts are exposed to great risks.
Today, ceramic materials are used in a variety of applications, depending on the characteristics, they can be used as insulation materials, bulletproof materials, wear-resistant surfaces, precision instrument materials, and electrical insulators. There is even a special kind of ceramic that can be changed from an insulator to a superconductor under ultra-low temperature conditions.
These ceramics have thousands of processing methods and they are manufactured in different ways. Many people may ask: Since ceramics have such strong resistance to deformation and wear, how should they be processed? This is indeed a technically demanding problem, and the general production process can’t handle it.
Ceramic materials will also be used on aircraft
In general, the process of making a ceramic material is first molded, then heat-treated (sintered) until the material reaches the desired density, and finally ground. Although ceramics are very hard, they are not the hardest objects in the world. There are always things that are harder than them, such as diamonds. Therefore, diamond tools and diamond abrasives are often used in the processing of ceramics.
The process is the same when making a ceramic case or ceramic bezel. The ceramic slurry is now formed into the desired shape and then dried and cured. The shape at this time is definitely not perfect, so you need to use diamond tools for further polishing. After the shape is polished, the temperature and pressure changes are used to sinter the ceramic until a satisfactory density is obtained. During the sintering process, the ceramic material will shrink to a certain extent. This shrinkage phenomenon is divided into three stages. The degree of shrinkage in the middle stage is the most severe, and the degree of each different ceramic material is different, so if In order to get the desired finished product size, it must be accurately predicted and controlled throughout the process. After the sintering is completed, it is also necessary to use a diamond tool for grinding and polishing.
Due to its strong hardness and wear resistance, ceramics are now very popular in the watch industry, and they are often seen in exterior parts such as cases, bezels, and mirrors. Of course, like all other materials, ceramics have their own drawbacks, such as too high a brittleness, which makes them rarely used on the movement.
The information about ceramics is all-encompassing. The above is just the tip of the iceberg. I just want to make everyone more aware of what ceramics are, how they are made, and how they can be applied. In this way, everyone knows how to choose expensive ceramic watches.
Would you buy a watch made of ceramic material?