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Dresden, Germany

Zgalat-Lozynskyy O.,Ukrainian Academy of Sciences | Herrmann M.,IKTS | Ragulya A.,Ukrainian Academy of Sciences
Journal of the European Ceramic Society | Year: 2011

Consolidation of commercially available nanostructured titanium carbonitride (TiCN) powder has been performed by Spark Plasma Sintering (SPS) in the temperature range from 1300 to 1600°C. The effect of non-linear heating and loading regimes on consolidation of high melting point nanocomposites has been investigated. SPS consolidated TiCN material has demonstrated near fully dense and fine homogeneous microstructure with average grains size about 150nm. Nanohardness and fracture toughness of the TiCN nanocomposite have been measured as 33±0.9GPa and 3.2MPam1/2 respectively. © 2010 Elsevier Ltd. Source

Zgalat-Lozynskyy O.,IPMS | Herrmann M.,IKTS | Ragulya A.,IPMS | Andrzejczuk M.,WUT | Polotai A.,MRA Laboratories Inc
Archives of Metallurgy and Materials | Year: 2012

Consolidation of commercially available titanium nitride nanostructured powder as well as nanocomposite powders in the Si 3N 4-TiN and TiN-TiB 2 systems have been performed by Spark Plasma Sintering (SPS) in the temperature range from 1200°C to 1550 °C. The effect of non-linear heating and loading regimes on high melting point nanocomposites consolidation has been investigated. Source

Zgalat-Lozynskyy O.,IPMS | Andrzejczuk M.,WUT | Varchenko V.,IPMS | Herrmann M.,IKTS | And 2 more authors.
Materials Science and Engineering A | Year: 2014

A superplastic deformation of pre-sintered Si3N4-based nanocrystalline ceramics and Si3N4 nano-whisker reinforced composites has been investigated. Superplastic deformation tests have been carried out in the temperature range from 1500 to 1600°C under 56kN compression in nitrogen. During the tests, all nano-composites exhibited high rates of deformation (1.6-5.4×10-3s-1) corresponding to high activation energy in the range of 538-699kJ/mol. The composites enhanced by Si3N4 nano-whiskers exhibited the formation of anisotropic microstructure with anisotropic mechanical properties. The highest Vickers hardness ~19GPa and lowest coefficient of dry wear 0.39 was exhibited by the TiN-Si3N4 nano-composite. © 2014 Elsevier B.V. Source

News Article | April 7, 2016
Site: http://www.rdmag.com/rss-feeds/all/rss.xml/all

Researchers have developed a particularly flexible additive manufacturing method that allows them to produce bone implants, dentures, surgical tools or microreactors in almost any conceivable design. At the Medtec medical technology tradeshow in Stuttgart, Fraunhofer scientists will show their research results. The small pharmaceutical plant next to the patient’s bed is no bigger than a two-euro coin. With wires and channels that are just a few hundred micrometers wide, it constantly mixes various drugs — painkillers, blood thinners and antibiotics — and fine-tunes them to the patient’s current health condition. A futuristic scene of modern microreaction technology that doesn’t yet exist in hospitals. The Fraunhofer Institute for Ceramic Technologies and Systems IKTS in Dresden is working to change that in the near future. The researchers are focusing on suspension-based additive manufacturing methods and combinations of them with other manufacturing techniques to create not only microreactors, but also bone implants, dentures and surgical tools. At Medtec in Stuttgart from April 12 to 14, they will be presenting a technological solution for creating medical components in almost every conceivable design using additive manufacturing methods. “We have no limitations in terms of type or color of material for the target components. This allows us to process ceramics, glass, plastic or even metal using thermoplastic 3D printing. One more advantage is that several different materials can be produced at the same time,” says Dr. Tassilo Moritz from Fraunhofer IKTS’s “Materials and Processes” business division. In the lab, the scientists have already successfully made components out of high-performance ceramics and hard metals. Now, they are looking for partners to put their technology to real-world use. One area in which the multi-material approach is important is surgery: endoscopes frequently employ an instrument to first cut open tissue, and then quickly close the blood vessels back up again using electric current. To prevent electricity from shocking the patient, the instrument needs not only high-grade steel, but also insulated ceramic components. “Ceramic substances are often well-suited for medical devices and components. Ceramics are sturdy and can be cleaned thoroughly,” explains Moritz. Researchers arrived at their additive manufacturing method as a result of their expertise in ceramic materials and process technologies. The key to their technology lies in preparing optimum ceramic or metallic suspensions. The mixtures rely on a thermoplastic binder that becomes liquid at temperatures of around 80°C. This is a crucial point in additive manufacturing: it means the suspensions can quickly cool down, and one layer after another can be deposited in sequence. In this binder, they disperse powder particles of metal, glass or ceramics. “Our mixtures are very homogenous, and we precisely set the optimum level of viscosity. Only then can the printer put out the droplet size suitable for the particular component contour. Our mixtures can’t be too liquid or thick. To achieve this, we have to master the preparation technique,” says Moritz. The electrically generated temperature in the printer melts the suspension. After deposition, the droplets immediately harden as a result of the quick cooling process. The workpiece is then built up point by point on a flat platform. This allows different materials to be deposited at the same time via multiple application units. “Another challenge is adjusting the behavior of the different suspensions during the subsequent sintering of the components, to prevent any defects,” says Moritz. “To this end, we modify the initial powder through special grinding processes.” In sintering, finely grained ceramic or metallic substances are heated under pressure. The temperatures of the substances remain so low that the structure of the workpiece does not change. Moritz is hoping for great things from these new options for microreaction technology based on ceramic components. Until now, production technology has prevented a breakthrough in miniature chemical plants. Their use had previously been limited to research labs in the main. That could change: “We can now build ceramic components that fit the application instead of the production process,” says the materials scientist. “To date, ceramic microreactors have mostly been milled out of plates. Internal and external sealing have always been a technological challenge for this. And there has been the problem of making connections that fit. Now, we can just print them onto the ceramic component during manufacturing in whatever form.” This benefits not only doctors, but also pharmacists and chemists. In most cases, they are processing very expensive or hazardous substances. “It is more affordable and safer to first work with minimal quantities in a microreactor,” says Moritz.

News Article
Site: http://phys.org/technology-news/

Floating homes are becoming increasingly popular in Germany – not only as holiday homes, but also as permanent residences. The Lusatian Lake District (Lausitzer Seenland) is particularly suitable for such a lifestyle: with its 23 lakes and a surface area of over 32 000 acres, it is the largest artificial lake district in Europe. Over decades, the region, which is located between the German states Saxony and Brandenburg, had been characterized by open-cast lignite coal mining. In the coming years, this way of life of living on water will help enhance the region's attractiveness and boost its economy. This is also the objective of the Lusatian autartec project, which the two Fraunhofer Institutes based in Dresden, the Fraunhofer Institute for Transportation and Infrastructure Systems (IVI) and the Fraunhofer Institute for Ceramic Technologies and Systems (IKTS), are involved in, as well as other partners from the region such as medium-size companies, manufacturers, the Technical University of Dresden (TUD) and the Technical University of Brandenburg (BTU). They will all work hand in hand to build a floating home on Lake Geierswalde, to the northwest of the city of Hoyerswerda, by 2017. This floating home will not only look elegant, it will also be able to provide for its own water, electricity and heat. "These kinds of energy self-sufficient floating homes do not exist yet," says autartec project coordinator Professor Matthias Klingner of IVI. Many lakes in the Lusatian Lake District are cut off from infrastructure such as water and energy supply. "We want to find a solution for this kind of environment," says Klingner. Standing on a 13 by 13 meter steel pontoon, the house extends over two levels and offers 75 square meters of living space on the ground floor, and another 34 square meters on the first floor. A 15 square meter terrace overlooks the entire lake. The house combines modern architecture and structural engineering with state-of-the-art equipment and building facilities. For example, solar cells are integrated in the building envelope and lithium polymer batteries store the collected energy. In order to save space, the battey systems developed at IVI are integrated into the textile concrete walls or into the stair elements. Researchers at IVI are also working on the efficient provision of heating and cooling systems. A salt hydrate fireplace provides heat on cold winter days: above the fireplace there is a tub filled with water and salt hydrates. "When the fireplace is on, the salt hydrates liquefy and begin to absorb heat," Dr. Burkhard Fassauer of IKTS explains. When the salt hydrates are completely liquefied, the thermal energy can be stored almost indefinitely. In order to release the heat when required, radio-based technology is used to induce crystallization. The principle is known from pocket warmers: to induce crystallization, a metal disc inside is clicked so that the pocket warmer solidifies and gives off heat. When heated in water, the crystals liquefy and the heat is stored until the next click. However, a fireplace is not enough to heat the house during the winter. This is where a zeolith thermal storage unit in the pontoon can help: the zeolith minerals are dried during the summer – a purely physical process in which heat is stored. "In winter, the moist air is enough for the storage unit to give off heat," Fassauer explains. An adiabatic cooling system provides for cool air in the summer. Unlike conventional air conditioning systems, it does not require electricity but uses the principle of evaporative humidification to cool. A surface on the side of the house is landscaped and moistened and the process of evaporation then cools the building envelope. The experts at IKTS are responsible for the water supply in the houseboat. "We are currently developing and experimenting with a closed loop system for drinking and service water," Fassauer explains. To accomplish this, the scientists rely on a combination of ceramic membranes and various electrochemical and photocatalytic processes. Ashore, wastewater is usually treated using biological processes. This is not possible in a floating house. "We must rely on physical and chemical methods. Thus, ceramics provide very efficient ways to bring together processes like photocatalysis, electrochemistry and filtration in a confined space," says Fassauer. Other materials such as steel and plastic would fail in such aggressive processes. The equipment for the circulatory system will be accommodated in the pontoon. Explore further: University of Stuttgart gets a research house for solar heat storage

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