Advanced Ceramic Materials – Martin Trunec

The research of our group is focused on the development of new processing routes for ceramic materials and development of novel ceramic materials with enhanced properties, particularly biomaterials, structural ceramic materials and materials for energetics and ecology.

• Biomaterials

In this research field we investigate novel composite biomaterials that can induce the growth of connective tissue on the surface and within the structure of implants and thus accelerate healing processes and additionally improve the strength and biological stability of the implant-tissue interface connection. These ceramic materials can be used as soft and/or hard tissue replacements, materials for orthopaedic devices, materials for drug-delivery etc.

• Materials for energetics & ecology

We design, process and characterize ceramic based materials and composites with functionally graded structures for improving the efficiency and lifetime of components and devices for energetics. The utilization of such materials is beneficial for energy harvesting, conversion and energy storage or as catalysts for the decomposition of gaseous pollutants.

• Structural materials

Our research group optimise classic ceramic systems and processing routes to obtain structural ceramics and ceramic composites with excellent mechanical and thermal properties, enhanced transparency and excellent optoelectronic properties, eg. ballistic armour, thermally and chemically resistant ceramic composite materials, abrasive-resistant ceramic composites, etc.

• Armours

Our team is producing ballistic-resistant ceramic armours. Such materials could be used as a part of ballistic inserts in bulletproof vests as well as the protection of light tactical armoured vehicles. It is usually not difficult to produce high-tech materials which are better than those commercially available but our research is mainly focused on solutions which are applicable for mass production and still provide high-level protection and lowered armour’s weight. Together with our partners we are capable to provide the final solutions including necessary certificates in the field of advanced oxide, non-oxide and hybrid composite ceramic materials.

• Bioceramics

We develop novel ceramic and composite biomaterials with improved mechanical and biological properties including the development of processing methods of these materials focused on personalized medicine. We are able to design customized processes for manufacturing of osteoinductive ceramic and composite scaffolds with hierarchical architecture for bone regeneration.

• Filters and membranes

We design, process and characterize ceramic based porous materials such as filters and membranes. We use many processing routes, including slip casting, gel casting, extrusion, partial sintering etc., to produce porous structures. 

• Electroceramics

The advanced ceramics is the key part of many electronic components used in present and future electronic circuits. These materials are usually utilized for their dielectric (insulating) properties, but other important applications as piezoelectric and/or ferroelectric and/or ferromagnetic materials have to be mentioned. Despite our team have experience with production and characterisation of all above mentioned groups, the research is lately focused mainly on lead-free piezo-ceramic and dielectric materials. At the same time, the basic research of ferroic and multi-ferroic materials is conducted.

Advanced ceramic materials

The main activity of the research group is to investigate advanced methods of preparing multifunctional homogeneous and heterogeneous ceramic materials (biomaterials, electromaterials and structural materials), to characterize their structure on various dimensional scales, to quantify structure-property-function relationships on the various structural levels and to develop procedures for engineering the properties of this class of materials in the process of their preparation.

Expertise, processing and characterization

• Particles and fibres synthesis

We use and innovate traditional as well as non-conventional techniques for synthesizing of ceramic oxide particles. The research is aimed on synthesis of particles with controlled morphology and composition especially by wet chemical techniques (sol-gel, precipitation, polymeric method…) using microwave, ultrasound and other high-energy fields. We utilize electrospinning and dip-coating methods for fabrication of ceramic and polymer/ceramic composite fibres with controlled size, shape and arrangement.

• Shaping technologies

In Advanced Ceramic Materials group, we use different shaping technologies and smart processing that allow us to work with a wide range of materials. We have a lot of experience with various wet and also dry shaping techniques such as slip casting, gel casting, freeze casting and tape casting, electrophoretic deposition, injection moulding, extrusion and co-extrusion, press forming via die press, uniaxial and isostatic pressing.

• Ceramic 3D printing and CAD/CAM machining of ceramic parts

We are very well established in the field of 3D printing (additive manufacturing). It means that we are able to produce three dimensional objects of diverse complexity by stacking individual layers straight from CAD data. Our group is also able to produce ceramic complex parts using CAD/CAM machining of ceramic blanks – from the blanks fabrication, through CAD/CAM design and machining to final sintered product. We use 5 axes CNC milling machine equipped with diamond tools, capable high speed machining operations. These technologies allow the production of high-performance ceramic parts mainly for testing part’s design and functionality or fabrication of prototypes, single parts and small-scale series.

• Sintering

The high temperature diffusion process called sintering is the key step in the production of all advanced ceramic materials. The driving force of this step is lowering of the surface energy. In the case of special and/or high performance materials, it is very difficult to optimise whole process. The final mechanical, functional or physical properties can be deteriorated by high residual porosity content, enormous grain size or other unwanted phenomena. Thanks to our know-how and experience, we are capable to provide extensive analyses of sintering behaviour (via dilatometry measuring, numeric modelling and calculations) and prevent such negative effects and optimise sintering procedure to achieve demanded quality of the final product.

• Particle, powder and ceramic analysis and characterisation

Basic characteristics of the particles, powders and ceramic bodies in green or sintered state (particle and grain size and shape, surface area, porosity, phase and chemical composition, thermal behaviour) are analysed by means of laser diffraction, scanning electron microscopy, BET method (using nitrogen adsorption), X-ray diffraction, energy dispersive spectroscopy and thermogravimetry coupled mass spectroscopy.

Catalytic performance of ceramic particles and powders can be characterized using reactors in a liquid and gaseous reactant medium with a reaction product analysis using mass spectrometry.

We can determine micro-rheology using dynamic light scattering, zeta potential and electrophoretic mobility using electrophoretic light scattering, and molecular weight using static light scattering. Rheological characterisation includes polymers, liquids, adhesives and other samples using a wide range of shear and extensional conditions.

Key equipment

­­Laboratories are equipped with devices for synthesis, shaping and sintering of advanced ceramic materials and for characterization of their properties.

• Ceramic particle and fibre synthesis

Microwave hydro/solvo-thermal reactor (up to 300 °C, 200 bar), ultrasonic probe/reactors, lab spray dryer, electrospinning machine.

• Shaping and preparation of ceramics

Ceramic injection moulding machine, double-screw ceramic extrusion machine with granulator, electrophoretic deposition gauge, tape-casting machine, uniaxial ceramic press, cold isostatic press, CVD system (up to 1600 °C), 3D printing machine, drying climatic chamber, 5-axes CNC milling machine (for milling of ceramics).

• Low and high temperature processes

Low temperature furnaces (up to 1200 °C) and furnaces for thermal and catalytic debinding, high temperature superkanthal furnaces (sintering up to 1800 °C in air atmosphere), high temperature furnace (sintering up to 2300 °C in vacuum, hydrogen, resp. inert atmosphere), hot press Spark plasma sintering (sintering up to 2400 °C with possibility of uniaxial pressure 80 MPa and heating rates up to 1000 °C/min), high-temperature furnace with rapid heating rate, two high temperature dilatometers working in temp. range from -150 to 1750 °C in air or up to temperature of 2000 °C in inert atmosphere.

• Analytical and other equipment

Particle size, specific surface-area and pore-size analysers, thermogravimetrical (TGA-DTA/DSC) analysers with possibility of TGA on samples with large volume – up to 17 ml (sample of 50 mm in height and 20 mm in diameter), liquid chromatograph, mass spectrometer, equipment for rheological and electrokinetic measurements, systems for testing thermal and (photo)catalytic properties of ceramics, equipment for characterization of piezoelectric materials, complete ceramographic laboratory, very precise analytical scales and other.

Cooperation

» Kulicke and Soffa (IL) – Sintering analyses of ceramic materials via high-temperature dilatometry.

» BOSCH (CZ) – Measuring of thermal expansion of ceramic composite plates.

» Energovýzkum (CZ) – Research on the technological and material properties of powdered materials.

» Somet Teplice (CZ) – Sintering analyses of new construction materials.

» Škoda JS (CZ) – Study of mechanical properties of containment material for the storage of nuclear waste.

» Lithoz (AT) – Thermogravimetrical analyses and high-temperature dilatometry of Al₂O₃ samples.

» ZrO₂ (CZ) – Development of ceramic semiproducts for milling of ceramic dental structures.

» CoorsTek Turnov (CZ) - Characterization of ceramics for ballistic armours.

» EMPA (CH) – Research on ceramic core-shell composite rods via thermoplastic co-extrusion.

» MUni Brno (CZ) – Research on the processing of highly flexible Al₂O₃ and ZrO₂ electrodes for plasma discharge.

» Stockholm University (SE) – Sintering of transparent alumina ceramics via spark plasma sintering.

» Josef Stefan Institute (SI) – Co-operation on the processing of mesoporous ZrO₂.

» University of Duisburg-Essen (DE) – Research on the nanoparticle processing technology.

» ICMATE-Genova (IT) – Hydrothermal syntheses of electroceramics.

» ASCZ-IPM (Academy of Science, CZ) – Research on mechanical properties of ceramic materials.