What is industrial ceramics?
In our daily lives, we encounter ceramics in a wide variety of forms. For consumers, it is primarily present as tableware porcelain or in the form of sanitary ceramics. In these areas, the focus is on hygiene and aesthetics. High-performance or industrial ceramics, on the other hand, perform their numerous tasks more in the shadows. They are valued for their numerous positive properties.
Zirconium oxide industrial ceramics - the different terminology
The term advanced ceramics was coined more than three decades ago. The aim was to draw a distinction from traditional clay-based ceramics. At the same time, the term served to group together materials that are also suitable for technical applications. For this reason, the synonym "technical ceramics" is also frequently used.
Different designations with similar meanings
In this context, further, mostly historically evolved terms with partly overlapping meanings are used for the different sub-areas. Materials whose focus is on withstanding mechanical loads are assigned to the group of structural or engineering ceramics. The terms engineering or industrial ceramics have a practically identical meaning.
Functional ceramics
The family of functional ceramics, on the other hand, comprises materials whose inherent properties are used for an active function. These include, for example, ceramic components with electrical, magnetic, optical or dielectric characteristics.
Electroceramics
The so-called electroceramics refers to materials that are used in electronics and electrical engineering due to their selected properties. More than a century ago, porcelain was first used as an electrical insulator. This was its first technical application.
Cutting ceramics
Drilling, turning or milling: the completion of these tasks has long since ceased to be dominated by metallic tools. Due to extremely high resistance to wear and heat, cutting ceramics are predestined for the manufacture of tools for hard machining.
Different properties, one commonality
Depending on their composition, the various advanced ceramics have different properties. But all materials have one thing in common: they are mainly made from non-metallic, inorganic, synthetic raw materials. This requires that they first undergo a special preparation process. Then the material can be shaped into the desired form.
To give the product the required strength, a high-temperature or firing process is carried out at the end of the production process. If the required tolerances in dimensional accuracy or a desired surface quality have to be achieved, this is often followed by an additional machining step.
How are the properties of industrial ceramics determined?
The material composition and the respective microstructure determine the individual properties of high-performance or industrial ceramics. The size scale is shifting further and further down to a few nanometers.
Even small admixtures or dopants play a decisive role. The situation is similar for the processes at the grain boundaries. There, specific dielectric or electrical properties must be constantly generated.
Materials for extreme conditions: modern industrial ceramics
Modern means of transport are becoming increasingly efficient and powerful. This also places increasing demands on the materials used. It is therefore not surprising that technical ceramics are also permanently on the advance in aviation.
One particularly exciting material that could increasingly serve as a high-performance replacement for metallic components in turbines in the future is textile-reinforced ceramics - so-called ceramic matrix composites or CMCs for short.
Ceramics are widely considered to be very hard and at the same time brittle materials. If defects occur in the grain structure, this can lead to catastrophic failure of the materials. For applications in dynamic loading scenarios, this meant a limitation.
Oxide ceramic matrix composites (O-CMC) address precisely this point. For this reason, they have been increasingly used in recent years, especially in the field of plant and energy technology.
The material is highly resistant to oxidation and has a low density compared with metallic materials. Furthermore, it possesses high strength in conjunction with damage-tolerant fracture behavior. All these properties mean that the material has great potential for use in gas turbine systems, among other applications.
Spray freeze aganulation for the production of the highest quality ceramic granules.
During the manufacturing processes of modern materials, the slurries used play a crucial role. For the production of ceramic granules, slurries are the basis.
These can also be non-fiber-reinforced technical ceramics. The granules serve as starting material for many shaping processes of ceramics. Especially for dry pressing, the granules are usually the selected raw material form.
For reproducible mold filling, the granules must have good flowability, homogeneous distribution of the individual raw materials and good granule compressibility.
Spray drying processes have become established for the production of ceramic granules. A solution consisting of solvent (usually water), ceramic powder and organic additives is sprayed in a spray tower in the form of fine droplets.
A hot air stream causes the droplets to fall to the ground. The solvent contained in the droplets evaporates, and a solvent-free granulate is formed. It is then discharged at the bottom of the spray tower. Granules obtained in this way are proven raw materials not only for insulators or sealing discs.
Increasing demands on ceramic products
Due to the increased use and changing conditions, the demands on ceramic products are increasing. Furthermore, completely new products are constantly being developed from high-tech materials.
In many cases, realization with classic ceramic granulates is no longer possible. Examples include transparent ceramics or medical technology components that have to meet the most stringent requirements.
If ceramic granules are produced by the conventional method, this has various disadvantages. If the starting raw materials are unevenly distributed in the granules, this can lead to so-called binder segregation on the granule surface.
Due to the manufacturing process, the granules have a hollow shape. As a result, they exhibit high strength. In the worst case, this means that they do not disintegrate uniformly during compression. Undesirable shell structures are visible in the end product.
The formation of very solid agglomerates in the granules is another relevant disadvantage. The agglomerates, some of which are very solid, cannot be destroyed during the pressing process. As a result, sickle-shaped or crack-like pores (defects), density gradients and indestructible granule structures can occur in the ceramic body.
Eliminating the disadvantages
If ceramics exhibit defects, these lead to a significant weakening of the components. This makes it necessary to develop granulation processes that eliminate these disadvantages.
The Technical University of Nuremberg, for example, developed the so-called spray freeze-drying process. In contrast to the conventional process, the droplets do not pass through hot air but liquid nitrogen.
FC Flexible Ceramic - highly elastic all-rounder for many industries
Zirconium oxide (Zr02) is one of the oxide ceramic materials. The addition of certain oxides results in a high-performance ceramic. On the one hand, it exhibits the typical ceramic characteristics such as corrosion resistance and temperature stability.
On the other hand, it has properties that are rather atypical for this material and are only known for metals. These include very high strength and toughness. If zirconia is called "ceramic steel", it is doped with yttrium oxide (Y203) as a stabilizer.
Our High Impact Ceramic made of zirconium oxide is a modern specialist with many positive properties:
It is highly elastic and at the same time exceedingly stable. For example, an 18 cm long blade made of FC Ceramic can bend by around 5 cm without being damaged.
If the material is struck and cracks form, the resulting cracks do not spread.
Comparing FC Flexible Ceramics with conventional standard ceramics, the impact-resistant FC material retains its mechanical strength.
This is a decisive factor, especially when applied to cutting tools: the micro and macro chip resistance of a blade is synonymous with a long-lasting product and perfect sharpness.
At 15 MPa, the HIC material has a very high fracture toughness Klc.
Excellent values in the 3-point bending test by EMPA Zurich. Let the video evidence convince you.
Have you ever dropped a classic ceramic knife? If the blade hits the ground, it either breaks right through or parts splinter out. Here, too, the FC Flexible Ceramic can convince all along the line. Even from a height of 3.5 m, a knife blade survives a drop test without damage.
Modern industrial ceramics from BSQ Tech GmbH
It is impossible to imagine the modern ceramics industry without high-quality ceramic granules. Especially in sectors with high demands on durability, temperature and chemical resistance, technical ceramics are opening up more and more potential applications.
As an experienced manufacturer and developer of high-performance and industrial ceramics, BSQ Tech is at your side from the initial idea to the finished product.
Contact us, we will be happy to advise you!