17. Oct. 2021

Applications of ballistic-resistant ceramic composites have been the subject of research for Martin Kachlík and Jakub Roleček from the Advanced Ceramic Materials research group at the CEITEC BUT for the past eight years. For better communication with industrial partners, they have decided this year to launch the TriCera spin-off to help bring their products to the market as rapidly as possible.

"We set up the TriCera spin-off to speed up the transfer of our technologies into practice. Companies usually want everything right away, which is sometimes a problem at university, and communication is easier when it is B2B (business to business)," explains Martin Kachlík. The research group in which he works is looking for applications for advanced ceramics in many sectors. "There are many applications: from bioceramics used in healthcare, for example as bone implants or dentures, to electroceramics, which are various capacitors or piezoceramics, to military and security applications, such as transparent or ballistic resistant ceramics, which is what we focus on the most. While some of these applications will take years to reach everyday use, it is the military applications that are closest to practical market introduction," says Kachlík, whose surname predisposed him to such research.

For example, it is still common to see all-metal armour on military armoured vehicles today. However, these significantly increase the weight of the vehicles, which can then have problems in the field if their construction is not built for such loads. "Sometimes, paradoxically, sponsors prefer a heavy steel solution for fear of degrading the polymer binder that attaches the ceramic armour to the bodywork, for example when military equipment sits in storage for years, so that the ballistic protection retains its properties," Kachlík explained the thinking of some institutions. The all-metal armour is also used for portable protective shields to protect, for example, bomb squads or police officers in the field. However, these have a high weight, and there is a risk that at a certain angle a missile will "slide" on them and can injure someone who was standing around the corner. The combination of aluminium and ceramic will safely embed the bullet.

The combination of bonded ballistic-resistant ceramic and Kevlar, which is significantly lighter than all-metal armour, has been used for decades. However, the adhesives or polymer fibres applied here lose their properties in certain situations. "Today, there are a number of ballistic-resistant ceramic-polymer composites on the market. However, these have their own specifics, for example in terms of thermal application. At minus 30 degrees, for example, the polymer parts become brittle. High temperatures, such as those encountered in desert warfare, also cause significant degradation of these materials. Military vehicles protected by our armour could be deployed in both subarctic and desert regions," Kachlík says, adding: "Even Kevlar has a limited lifespan, which was evident in many cases in the USA, when police officers carried bullet-proof vests in the trunk of their cars for years and then it turned out that they were past their lifespan and did not work as they should," hinted at the possible risks of the scientist, who is working on the development of the new technology with, among others, the Turnov-based company CoorsTek.

The task of the team from CEITEC BUT was therefore to find a ceramic-metal connection without this organic component, which is at risk of degradation. The result is a material with no lifetime limitations, so it is certain to behave the same way in twenty years. It has high chemical and temperature resistance, and is also effective against fire, so even if a Molotov cocktail lands on an armoured car, the armour is sure to hold up, which can be useful in urban conflicts. Today's armored cars have to completely replace their armor at the point of impact after such an attack, because fire will destroy the polymer component. The solution offered by the TriCera spin-off is virtually fireproof.

"Our technology is unique in its concept, but at the same time affordable. As far as we know, there is no similar production of additional ceramic-metal armour in Europe. It is certainly strategic to have it right in the middle of the old continent, not only because of the threat of import embargoes," Kachlík points to the experience after the pandemic. Together with Jakub Roleček, they have assembled special ceramic parts in a tight arrangement and, thanks to the developed technology of a strong connection between ceramic and metal, they manage to better absorb the energy of the projectile even through the plastic deformation of the metal matrix.

"We have been cooperating with the Military Research Institute for a long time to obtain state certification of our materials. This confirms that the material can withstand a so-called multihit, where multiple missiles land close together," explains young researcher Kachlík, as he stands over black plates with different-sized craters that commemorate the shooting tests. The largest of them is the aftermath of a 20 millimetre shrapnel that flew at 750 m/s, simulating the explosion of a booby-trapped device. However, the ceramic-metal armour designed at the Brno facility withstood even such an impact.

There are many applications for this material: for example, additional armour for military armoured vehicles, blast protection, mobile protective shields for bomb disposal, safety boxes for transporting explosives or ammunition, protective doors for key objects and much more. The soft aluminium on the surface and the very hard ceramic inside guarantee that this material is virtually impossible to cut through or very time consuming. Thus, for example, safe deposit boxes and safes are offered as potential future applications. The scientists have already attracted the interest of a foreign visitor from the USA, who was interested in this strategic technology.

"We are therefore moving somewhere between a pure ceramic and a pure metal solution, thus taking advantage of the benefits of both. We work with an aluminium alloy, so there is no risk of corrosion. Our armour can withstand not only incendiary ammunition with hardened steel cores, but also those with tungsten carbide cores. If someone fires a penetrating projectile, shrapnel will fly off the classically bonded polymer ceramic that can injure someone. With us, the ceramic is safely hidden in an aluminium matrix to catch these large shards," says Kachlík, describing the other advantages of their solution. In addition to soldiers, the material could also be used by police officers, so the team has already submitted a project under the Ministry of the Interior to facilitate application by civilian security forces.

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