The Advanced Ceramics Laboratory offers a multi-disciplinary environment with extensive materials processing facilities and thermo-mechanical characterization techniques. Current research activities fall in three main areas: a) Hybrid materials for extreme environments, such as thermo-mechanical protection systems (TPS) for spacecraft (funded by the European Space Agency, ESA), b) functional industrial ceramics, such as heterogeneous catalysts for environmental protection and chemical synthesis and c) Reduction of environmental impact of production processes. In the first area, recent major developments are the “HybridTPS” system which is undergoing feasibility studies as well as the new BioPICA ablator system for ultra high velocity spacecraft. Recently, we succeeded in obtaining RD funding under a FP7/Space project “RASTAS SPEAR” on the further development of an ablating TPS for spacecraft. The lab also has a role in the FP7/Space project HYDRA on TPS development. A new FP7/Space project – PULCHER – has just started on 1 Jan 2013 to develop new rockets for exploration craft. In addition, we recently received an invitation to partake in a project on developing structural units on the Moon using lunar raw materials as well as to carry out SHS experiments under microgravity conditions. In the second area, we have developed very sensitive inorganic catalysts using the SHS method for use in vehicles and to increase chemical synthesis yields. This is the subject of a number of industrial projects. Our Microwave-assisted drying technology is aimed at the heavy ceramics, lignite and waste materials industries in collaboration with the manufacturing SME “AIT SA” of Thessaloniki, reducing substantially energy use and environmental impact. In this respect, end users of the MW heating technology (customers of AIT SA) include large ceramics manufacturers in Greece and Europe as well as the Greek Power Corporation for lignite processing. Finally, we are currently developing a new method, based on MW-assisted decomposition and electrostatic separation, for converting Carbon Dioxide to C, CO and O2, thereby reducing industrial emissions of CO2 from fossil-fuel burning plants.

ASTERM-Demo

Research Topics

 

 

Self-Propagating High-Temperature synthesis (SHS) of refractories, catalysts, intermetallics and other materials

The SHS method exploits highly exothermic solid-state combustion reactions for the synthesis of many engineering materials, many of them unique, with minimal use of externally applied heat. Although the starting temperature may be as low as ambient, the final combustion temperature may reach as high as 3000<oC, depending on the system and conditions. The method offers very significant advantages over traditional furnace-based methods, the most significant being lower overall energy usage and very rapid (seconds) synthesis times. Materials such as carbides, borides, nitrides, oxides, intermetallics, composites are produced at a fraction of the cost of traditional methods. Using SHS, in the Advanced Ceramics Laboratory we have developed a range of very active catalysts, refractories, inorganic pigments, high-temperature refractories and intermetallics. Currently, we are investigating new refractory compositions of MgO/MgAl2O4 (see our ESA-funded activities), new catalytic systems based on MgxCoyAl2O4 for pyrolysis of hydrocarbons, the system NixAlyOz for hydrogenation processes and various mixed oxides as industrial pigments.

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Hybrid engineering materials for spacecraft protection

Spacecraft entering a planetary atmosphere at very high speeds experience plasma-level surface temperatures as a result of friction with the atmosphere. The incident heat fluxes depend on the conditions (shape, speed, atmosphere etc) and can reach up to 30MW/m2, giving, over a transit time of up to 20-30 seconds, a total heat load of up to 700MJ/m2. Since no engineering material can sustain such heat fluxes, ablative thermomechanical protection systems (TPS) are used, made of carbon-phenolic composites, sometimes incorporating silicon. But these suffer from ablation-induced irregular surface recession and do not offer any protection against high-speed particulate impact. To address these limitations, we are currently developing 2 new types of TPS, with European Space Agency support. First, a “HybridTPS” composite made of a porous MgO-ceramic (made by SHS) filled with a phenolic ablator, which offers impact protection as well as almost no recession. Proof of concept has been completed and current work centres on enhancing the ablative heat-dissipation properties. A recent system under development, is the “BioPICA”, is a phenolic filled-carbon structure made by Microwave-assisted pyrolysis of wood. Vekinis3a

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Inorganic catalysts for Industrial and environmental applications

Inorganic catalysts are the back-bone of the chemical industry. Nearly all industrial chemicals are manufactured using catalysts, since catalytic materials increase the reaction kinetics by many orders of magnitude without actually taking part in the reaction. The same advantages are also conferred by catalysts for cleaning of environmental pollutants, e.g. in factory emission scrubbers and car exhaust pipes. Catalyst activity (and selectivity for particular processes) depends on the composition, the open porosity but also crucially on the amount of “active centres” on its surface, usually dictated by a degree of distortion of the atomic lattice. Most catalytic systems are industrial secrets and are specially developed for each process. We are developing new inorganic catalytic systems using the SHS method for a range of industrial and environmental applications, whereby the catalytic activity is enhanced by the creation of a large number of active centres and metastable, often non-stoichiometric compositions. The processes we are studying include ethylene and propylene production, deep oxidation of methane, CO oxidation, hydrogenation of naphtha and diesel and others and SHS catalysts offer significant improvements over existing industrial systems.

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Microwave processing for reduced environmental impact and energy use in industry

Drying and firing are the most energy-intensive processes during production of many products, such as ceramics etc. In large-scale industries, heating is nearly always carried out by the combustion of a fossil fuel such as gas or oil. For drying, forced hot air is used and the drying process can extend up to 5 days or more in a carefully controlled process. Firing is similar and the temperatures involved can reach 1600oC. In all such external heating processes, the main limiting factor deciding the effectiveness (and responsible for the high energy consumption and long duration) is the diffusion of heat from the surface to the centre of the material. To reduce both total energy consumption and process duration, we have developed Microwave short-pulse heating, applied during the drying or firing stages. Microwaves are able to penetrate non-metallic materials and by resonant coupling can heat up almost instantaneously polar molecules, such as water, in the body of the material. This leads to the heat and the contained water rapidly diffusing from the centre outwards where it is removed and, in industrial applications, it is possible to reduce energy consumption as well as duration by up to 75%. The technology has been spun-off to a new spin-off company “Advanced Industrial Technologies SA” which has successfully applied it to industrial drying chambers of volume greater than 100m3. Recent developments of our MW drying technology include continuous drying of clay masses and stone slabs, biological sewage sludge, lignite and other materials.The picture shows Roof tiles being loaded in an industrial MW-drying chamber in a plant in Northern Greece, made by AIT SA.

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Nanostructured materials for protection against Cosmic Rays

All organisms exposed to open space are bombarded by high energy particles such as Galactic Cosmic Rays and Solar Protons etc. For this reason all astronauts need to be protected by the use of materials shielding systems. The Advanced Ceramics Laboratory is developing a new protective shielding system made of a polyethylene matrix containingmagnetic partiels. A proposal to FP7/Space was submitted in October 2012.

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New spacecraft propulsion systems

For the new project PULCHER the Advanced Ceramics lab will develop a new type of combustion chamber for the new rocket engine to be developed by the coordinator, ALTA (Italy) for use on explorative spacecraft. The new chamber will have to withstand temperatures upto 3100oC and pressures of 5Bar. It is proposed to build it based on a shell of C/C composite and coat it with our lab’s own materials and methods. Pulcher-schematic

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Services on Mechanical and thermal properties

The Advanced Ceramics and Mechanical Properties Laboratory offers a wide range of services. For more information please visit: http://www.ims.demokritos.gr/Advanced-Ceramics/services-en.htm

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Advanced Ceramics Labaratory

The ACL covers a wide range of processing, characterisation and testing facilities for technical and advanced ceramic materials. This allows integrated study and development of a range of materials, aided by other facilities within IMS and “Demokritos” in general. In addition, we can offer services to industry and to other laboratories. The main equipment within the laboratory includes:

  • High temperature furnaces (1600oC, controlled atmospheres)
  • Microwave heating equipment
  • Wet chemistry and solid-state chemistry processing
  • Compaction presses and moulds (uniaxial, isostatic, hydrostatic)
  • Diamond processing for hard materials (cutting, grinding, polishing)
  • Optical microscopes
  • NSTRON mechanical universal tester
  • Universal Hardness tester (Vickers, Brinell, Rockwell)
  • Microhardness tester
  • Cavitation Ultrasonic tester
  • Gas chromatograph

Services offered by the Advanced Ceramics Laboratory

Technical consulting to industries and small to medium sized enterprises, active in the fields of traditional and advanced ceramics, metallic alloys and glasses

  • Measurements of mechanical properties (strength, hardness, toughness etc) of metallic, ceramic and plastic materials
  • Failure analysis of production processes, materials and products, aiming at the optimization of production processes and the reduction of non-conforming products and waste
  • Metallographic and ceramographic studies and determination of the mechanical properties of materials and products according to international standards (ASTM and ?? ISO)
  • Studies of mechanical and chemical wear (abrasion, erosion, corrosion etc) of all engineering materials and products
  • Determination and prediction of mechanical stresses and failure modes of products using Finite Element Analysis, including thermo-mechanical analysis

Characterisation of advanced ceramic coatings used in engineering applications:

  • Estimation of the adhesion strength of CerMet coatings (e.g. WC-based cermets) onto metallic substrates and numerical simulation of their behaviour via Finite Element Analysis
  • Study and prediction of the behaviour of coatings under surface mechanical loading and/ or chemical aggressive environment

Contact: Dr George Vekinis, +30 210 6503322, g.vekinis@inn.demokritos.gr