Institute of science and technology for ceramics (ISTEC)

Research activities

Our Research activities are addressed to develope new materials and processes, supporting, at national and international level, those scientific, industrial and cultural areas, where ceramic materials and devices find applications and drive the innovation.

Research activities are targetted to design materials with desired properties and improved performance. This is achieved starting from the synthesis/characterization of raw powders and mixtures and passing through optimized processes of forming and sintering both dense and porous materials, with simple or more complex shapes and controlled textures and properties. Coating technologies for surface functionalization and joining of dissimilar materials are of interest as well. Microstructure, mechanical and functional characterizations are associated to the development of processing technologies and evaluation of perspective performances of the materials and devices.

Research macro-areas of major interest:

CERAMICS FOR ENERGY - ENVIRONMENT - MECHATRONICS

Compositional design and production of ceramic devices with porous as well as more compact textures for energy, optical, electronic, electromechanical applications and sensing, through cost-effective, environmental friendly easy scalable processes.

- Dye Sensitized Solar Cells (DSSC) ISTEC is mainly involved in the design and optimization of the semiconductor ceramic layers for both rigid and flexible DSSC studying either the material and the deposition techniques. Moreover, the competences on glass ceramic systems are used to develop suitable sealing systems.

- High Temperature Ceramic Batteries:study of the production process, from the powders synthesis to the shaping and sintering needed to obtain ²"-alumina membranes either in tubolar and planar configuration with suitable morphological-structural characteristics.

- Solid Oxide Fuel Cells (SOFC) ISTEC activities mainly deal with the study and optimization of those ceramic processes cheap and easily scalable able to produce the above mentioned ceramic devices in an easy and envinronmental friendly way. ISTEC exploits the most common techniques used in the traditional ceramic industry: tape casting, die pressing, screen printing, powder wet spray, to optimize the production of the three generations of planar SOFC: electrolyte-supported cells, electrode-supported cells, metal-supported cells.

- Solid oxide electrolysers (SOEC) SOEC are produced at ISTEC starting from powders obtained by conventional solid state synthesis or chemical routes (precipitation, sol-gel, etc.). The powders are synthesized with characteristics suitable for the subsequent shaping processes. The cell fabrication consists in depositing the cell elements onto a supporting-element produced by tape casting. All the possible substrates for SOEC were produced with this technique

- Ceramic solar absorbers for concentrating solar power systems, mainly ultrarefractory materials based on afnium carbide and zirconium diboride.

- Piezoelectric materials for electro-mechanical applications. The piezoelectric ceramic materials research is oriented to: study of materials, in particular, " lead free ", development of massive components (dense or porous), production of thick films, for specific applications at low and high power over a wide range of frequencies.
Prototypes can be developed (designed and manufactured): piezoelectric sensors and actuators fully dense and porous; voltage transformers transducers.
Applications: Active vibration suppression, recovery of mechanical energy (energy harvesting), underwater acoustics, wearable devices, etc.

- Multiferroic materials and composites: the activity is currently focused on processes for the development of new materials and especially the production of composites by combining a magnetic material with a dielectric or ferroelectric material.

- Porous structures with complex architecture. ISTEC realizes ceramic or hybrid architectures with functional porosity (from the nano- to milli-metric size, globular or unidirectional, isotropic or anisotropic, graded, etc.) on the basis of the requirements imposed by the specific application areas (absorbers, filters, bone substitutes, dispensers of specific agents, catalysis, weight lightening, insulation, recycling, etc.).Near net shape technologies are mainly chosen, generally based on the use of ceramic or hybrid suspensions and blowing agents (direct foaming) or / and sacrificial templates (replica of polymeric sponges, freeze casting, polymer granules, metal powders). The use of water as the liquid medium and the possibility of exploiting some technologies for the recycling-disposal of waste is of interest in view of environmental protection.

- Tailoring of Hydroxi-apatite for energy production and absorption. HA is recognized as a very interesting material for environmental purification due to its ability to easily absorb a number of inorganic and organic compounds such as proteins and bacteria. In this respect, specific ion substitutions in the lattice of HA open the way to multi-functional and multi-purpose applications. The ionic substitution destabilize the HA lattice and yields an atomic re-arrangement that yields a decrease of the energy gap of the band structure of HA. In this condition, Ti-HA gathers photoelectronic properties that are promising for implementation into new dye-sensitized solar cells (DSSCs) for energy production, that are among the most advanced and promising ways of providing electricity in the absence of a main power supply.

CERAMICS FOR BUILDINGS, CONSTRUCTION AND HIGH-TECH APPLICATIONS

- building and construction materials, mainly clay-based ceramics. Recent innovations concern design and development of light components with reduced thickness and desired aesthetic features.
ISTEC has many years of experience in research activities in scientific and technological development of the ceramic industry for building and construction. Offers innovative solutions regarding both materials (ceramic tiles, ceramic slabs, bricks, lightweight aggregate, refractories, sanitaryware, tableware, etc.) and technological processes. ISTEC is dedicated to the study of the production process in order to evaluate the dependence of the main functional characteristics of the product on process parameters; relationships between characteristics of raw materials and properties of semifinished and finished products. Particular attention is dedicated to raw materials and the use of waste recicling.

- Ceramic Pigments and digital decoration. The process innovation from conventional to digital techniques in ceramic tiles decoration is driving new chances also to achieve product innovation. The pressure coming from higher expectations for colorant performance and stricter controls on both materials properties and synthesis mechanisms is turning ceramic pigments and dyes for digital printing into engineered products. ISTEC is contributing to set up new decoration technologies by developing inks, powders and their functionalization and synthesis procedures, in order to improve yield, stability and durability in the ceramic process.

- Ceramics for technical and structural application: oxides and non-oxides based materials, ceramic-ceramic and metal-ceramics composites for a variety of technical and engineering application. The development of ceramic composites that are electrical conductors and display good high-temperature structural properties is of great industrial interest. These composites are currently employed in applications as heaters, igniters. Composites made of insulating ceramics (such as alumina, silicon nitride, aluminum nitride, silicon carbide) and variable amounts of electroconductive phases (metallic, intermetallic or ceramic) can fulfill these requirements.The addition of a "lubricant" secondary phase such as h- BN allows high machinability.
Prototypes for several industrial sectors like mechanics, energy, transportation, aerospace and electronics are produced.

- Ultra high temperature ceramics (UHTCs, melting point range 3000K-4200K) are extremely interesting for thermal protections and propulsion in aerospace applications and for very high temperature industrial processes.IV and V group transition metals, like Ti, Zr, Hf, Ta, form borides and carbides that belong to a class of materials defined as Ultra-High Temperature Ceramics (UHTCs) for their high melting points between 3000 and 4000 K.Scientific activities concern: innovative processing for fabrication of dense or porous bulks, composites with fibers, whiskers, platelets, CNT; advanced characterization: high temperature thermo-mechanical, aero-thermal behaviour study (in collaboration), high resolution-TEM characterization, optical properties at room and high temperature (in collaboration);

- Geopolymers are ceramic-based composites which consolidate at low temperature through a cheap polymerization process, that is environmental friendly and low energy consuming. ISTEC studies and produces geopolymer-based materials for structural and thermo-mechanical applications, such as: panels for thermal insulation, soundproofing and fire-proofing, foams with a functional porosity for filters, catalysis, biomaterials, etc.

- Transparent ceramics based on YAG (for laser applications) and based on Mg-spinel, for transparent high strength windows. Cubic isotropic MgAl2O4 spinel can be regarded as an almost ideal transparent ceramic material. It is an attractive material in the aerospace sector for several applications under severe conditions such as hard front layer in transparent protection and rugged optical windows operating in harsh environment. At ISTEC we optimized the production process of spinel components with an in-line transmittance close to the theoretical value.

For the above mentioned classes of materials, the activities start from materials design, selection of raw powders, set up of processing procedures (forming/sintering/machining), characterization of microstructure, evaluation of mechanical properties up to high temperature, oxidation and corrosion resistance.

FUNTIONALIZATION OF SURFACES THROUGH NANOTECHNOLOGIES

The functionalization of surfaces generates considerable interest in various industrial fields from the ceramic one to that of metal and composite materials for aerospace and marine applications, to textile fibers, etc. In the recent years, the objective of ISTEC CNR activities has been to modify the surface reactivity of materials through the design and deposition of coatings - in the form of thin films - with the aim of modulating their wettability, and, in particular, increasing significantly their repellency against water. The control of the surface chemistry, especially in terms of surface energy lowering, is another parameter that can be optimized by deposition of superhydrophobic coatings. Metals or alloys with a very low surface energy are the best candidates to the construction of hulls or marine propulsion systems with the ability to greatly reduce the marine fouling, which greatly affects the speed of vehicles and the effectiveness of cleaning and removal of marine pollutants operations. A further advantage is represented by the ability of superhydrophobic surfaces in contact with different fluids to reduce friction in correspondence of the boundary layer. This has recently led ISTEC CNR to design components for axial pumps with high affinity towards lubricants molecules, achieving a significant reductions of friction coefficients.
As far as all the scientific areas we are dealing with, the durability of the effects and the mechanics of coatings are the key points on which ISTEC CNR, thanks to an extensive network of national and international collaborations, is focusing the attention. Due to the specific skills and availability of suitable processes at our disposal, we can build and characterize highly innovative materials for different industrial applications.

Chemico-physical and aesthetical features of surfaces can be modified through the deposition of coatings, glazes or inks, able to provide the materials (ceramics, composites, metals, textiles, etc.) of new functionalities and improved performances.

The surface features are conferred through the study of materials and processes, evaluating and optimizing all the involved parameters. ISTEC CNR is able to simulate the processes of surface functionalization, followed by the final assessment of the performance achieved, thanks to the strengthening of some deposition lines (dipping, spraying automated, ink jet printing) of coatings with controlled structure and chemistry.
Ceramic textiles are treated by means of the immobilization of Inorganic Nanoparticles (NPs) into textile fibers, let to obtain new organic-inorganic nano structured composites, joining both properties of traditional ceramic and textile materials.

MATERIALS FOR REGENERATIVE MEDICINE

The request of biomimetic materials for regenerative medicine is strongly increasing due to the raising of the number of pathologies related to life-styles and the progressive ageing of the population. The sectors of interest are orthopaedics, neurosurgery, maxillo-facial-dental and aesthetic surgery; in consequence of the loss of tissue due to traumas, degenerative pathologies or deformity, all these fields require bioactive and bio-resorbable scaffolds, able to be integrated by the human body, colonized by cells and remodelled so as to re-build the missing part of tissue. New research topics include:

- magnetic apatites for drug delivery sistems: bioactive hydroxyapatite nano-phases endowed with intrinsic superparamagnetism, designed to act as new stimuli-responsive drug delivery systems or to enhance cell homing and colonization of bone and osteochondral scaffolds thus enhancing tissue regeneration.

- porous implants for bone rigeneration: natural and bio-erodible polymers are also used in blends with the ceramic phase to enhance fracture strength and tailor elastic properties towards values typical of bones.

- bone cements; development of new phases that closely mimic the inorganic part of bone and exhibit good ability of osteogenesis and bio-resorption in vivo. These biomaterials are very suitable to be used as regenerative bone fillers in the form of granulate or as injectable pastes.

- nanocomposites for regeneration of multi-functional anatomical regions: 3D hybrid biomimetic and bio-resorbable scaffolds for the complete regeneration of multi-functional regions like osteochondral and periodontal sites are developed by a well-established bio-inspired synthesis mimicking the biologic neo-ossication process, thus providing the new devices with very high regenerative ability.

- bioactive impants with hierarchixcally organized porous structure: development of porous structures have been performed through the application of morpho-synthetic transformations of natural wood based-templates. It is possible to obtain calcium phosphate-based devices with regenerative properties, without altering the original structure-morphology.

- Studies on ceramic-cell interaction and biological evaluations are applied, to evaluate the biocompatibility and biofunctionality of novel biomaterials for regenerative medicine after trauma or degenerative diseases (e.g. osteoarthritis, osteoporosis). The in vitro studies investigate cytotoxicity, biocompatibility, biofunctionality, bioactivity of biological and synthetic materials. For therapies aimed at tissue regeneration, biomaterials will be studied also in association to biological stimulators (differentiated and dedifferentiated cells, growth factors and other signal molecules, biophysical stimulations).

- For the traditional prosthetic and dental sectors, new nano-structured materials are being developed, characterized by very low friction coefficient and very high resistance to fracture and wear. ISTEC has developed bioinert ceramics for minimal wear articular surfaces, load bearing implants, crowns, abutments and endoosteal implants, osteointegrated by bioactive coatings, electroconductive ceramic composites that can be machined in complex shapes by electrical Discharge Machining.

- Innovative nanocomposites containing apatites are studied for applications in air filters for moisture exchange and capture of nanoparticles: hybrid porous nano-composites to be used as filtering devices and moisture exchange systems are developed with complex geometry contributing to the water and nano-particles trapping (including the unrestrainable particle with dimensions in the range of 30-100 nm) without excessive pressure drop.

- HA for for energy production and absorption. HA is recognized as a very interesting material for environmental purification due to its ability to easily absorb a number of inorganic compounds as well as different organic substances such as proteins and bacteria. In this respect, specific ion substitutions in the lattice of HA open the way to multi-functional and multi-purpose applications. The ionic substitution destabilize the HA lattice and yields an atomic re-arrangement that yields a decrease of the energy gap of the band structure of HA. In this condition, Ti-HA gathers photoelectronic properties that are promising for implementation into new dye-sensitized solar cells (DSSCs) for energy production, that are among the most advanced and promising ways of providing electricity in the absence of a main power supply.

CULTURAL HERITAGE

Through archaeometric studies, it is possible to deduce the provenance of the raw materials and to define the working technologies of finds.
Microstructural, chemical and physical characterisations are basic for this scope.
The archaeometric information together with archaeological and historical ones allow to reconstruct the trade routes and the contexts of uses of the ancient objects.
The diagnostic investigations deal with the study of a multiple system, object-environment-interaction areas, focusing on the degradation phenomena and on their diffusion rate.
The analysis of deterioration mechanisms occurring in the ancient artefacts is important in order to plan targeted restoration interventions and correct conservation and maintenance programs.
New conservation materials are studied. The products for the conservation of the natural and artificial stone materials in the Cultural Heritage must be fit for the restoration function that they must perform. In addition they must be compatible with the materials on which you operate and durable in different environmental contests. Geopolymers, hydraulic mortars based on slaked lime or natural hydraulic lime NHL and meta kaolin meet all these requirements.