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ThermoOptical Measuring methods for the High Temperature Characterization of Refractories

Friedrich Raether1), Gerhard Seifert1), Jens Baber1)
Fraunhofer Center for High Temperature Materials and Design (HTL), Bayreuth, Germany, Tato e-mailová adresa je chráněna před spamboty. Pro její zobrazení musíte mít povolen Javascript.

Information on the high temperature material properties of refractories are the key for their successful application and for the development of new refractories. Due to the heterogeneous microstructure of refractories many standard methods for high temperature testing of materials are not applicable because the sample volume is too small. At HTL new measuring methods for the high temperature characterization of refractories are developed. These so-called ThermoOptical Measuring (TOM) methods aim at a full characterization of the thermal, mechanical and corrosion behavior of refractories at their operating temperatures. Especially a new measuring device, TOM_wave, is introduced. It measures thermal shock resistance, thermal diffusivity and other high temperature material properties by laser heating of samples in a furnace. In addition, a survey is given on the development of TOM devices for the high temperature investigation of other material properties. 

Water assists flash sintering to densify ceramic

   Sintering uses heat or pressure to compact individual particles together into a densified material. But while sintering has long been used to compact ceramics, the process is energy intensive, often requiring heating to very high temperatures for prolonged periods of time.So it’s no surprise that much research has been devoted recently to developing new varieties of sintering that consume less energy and fewer resources.

  Promisingisthe  technique  of flashing sintering, which uses an electric field to rapidly sinter ceramics at reduced furnace temperatures. Ever since its introduction by Rishi Raj and colleagues in 2010, much research has been done to explore the potential of flash sintering. Part of that research resulted not only in new and improved techniques, but lead to a better understanding of the flash sintering process itself.

Ceramic pump operates at 1174°C for thermal energy conversion

 Ceramic materials have outstanding properties-high temperature strength and melting points, extremely high hardness, high compressive strength, and dimensional stability. Depending on the specific material, they can be electrically conductive, thermally conductive or magnetic. That makes ceramics ideal for a number of applications, such as automotive parts that need heat-resistant characteristics and cutting tools for manufacturing that require excessive strength. The medical industry uses ceramic materials for bone and dental replacements. The aerospace industry uses ceramic materials in engines and missile nose cones to protect internal components from high heat. Ceramics contribute to environmental and solar energy industries in water treatment and power plant engines.
 

Graduate student Caleb Amy pours molten tin into a crucible. Credit: Georgia Tech

26.-29.9.2017 UNITECR 2017 in Santiago, Chile

 

  
Opening reception featured dancers representing the history and regions
of Chile—from Easter Island, the Mapuche people, Spanish settlers,
campesinos, and people from the northern regions, as well as
the Patagonia region in the south. Credit: ACerS


In September 2017, the refractories industry gathered  in Santiago, Chile, for the 15th Unified International Technical Conference on Refractories (UNITECR). The conference was organized and hosted by ALAFAR, the Latin American Refractories Association.
 Pablo Valenzuela, president of this congress said “I am most proud of two things. One, the Latin flavor in all the social matters, and two, the quality of the papers is really good.”
 The organizing committee was selective in the papers it accepted. Valenzuela says, “We didn’t want a competition [with previous UNITECRs] on quantity of papers, but on quality. We wanted new subjects, new investigations, and technological advances.”

OWENS CORNING TO ACQUIRE PAROC GROUP, A LEADING EUROPEAN MINERAL WOOL MANUFACTURER

    Owens Corning  announced that it has signed an agreement with CVC Capital Partners to acquire Paroc Group (“Paroc”), a leading producer of mineral wool insulation for building and technical applications in Europe, for an enterprise value of approximately €900 million. The transaction, which is subject to regulatory approvals and other customary conditions, is anticipatedto close in early 2018.
   Paroc is a leading European manufacturer of high-performance mineral wool insulation solutions for a variety of end markets. Paroc manufactures building insulation for thermal, fire and acoustic applications in residential and commercial construction. The company also manufactures technical insulation for HVAC systems; industrial processes; and the marine, offshore and original equipment manufacturer industries. Mineral wool products are customarily known as stonewool in Europe.

BJS Ceramics and Fraunhofer expand SiC ceramic fiber pilot plant

The Fraunhofer Center for High temperature Lightweight Construction location in Bayreuth, Germany, will be expanded by a ceramic fiber pilot plant for oxydic and non-oxydic ceramic fibers. The ceramic fiber plant will start up in January 2019. BJS Ceramics GmbH from Gersthofen, Germany, is a key partner.
  Non-oxydic ceramic fibers, so-called silicon carbide (SiC) fibers are used in SiC-fiber-reinforced composite materials. Fiber-reinforced composite materials uniquely combine important characteristics such as high-temperature resistance, high mechanical strength, high resistance against aggressive media like acids or salts – while being light-weight. Many industries rely on this highperformance material, e.g. the aviation industry. This composite material enables more efficient turbines for airplanes that will meet the future regulatory limits for emissions.

Laser melting initiated deeper structural heterogeneity in oxide ceramics

Lu Song1*, Jing Ma1, Yafei Wang1, Qinghua Zhang1, Ben Xu1, Zhijian Shen1,2 1 School of Materials Science and Engineering, Tsinghua University, Beijing 100084, P. R. China           

   Selective laser melting, as a kind of additive manufacturing process, has proven itself a powerful method in manufacturing of customized parts, made especially of metals and alloys. Besides the success in 3D net-shape forming, this process has been recognized by its dynamic and non-equilibrium characteristics, which has enabled the formation of amorphous metals and high-entropy alloys.

New microscope technology provides a detailed look at structure and composition of materials

 At their core, electron microscopes work a lot like a movie projectors. A high-powered beam passes through a material and it projects something — usually something we really want to see — onto a screen on the other side. With most electron microscopes, however, capturing data is like trying to project a movie onto a dirty screen that is too small to see the whole projection. But a new camera technology, tested by researchers at Drexel University, is enabling the microscopes to present a clearer, more complete and detailed look at their featured presentation.
 Using a direct detection camera and an image filter, the group discovered that it can obtain a crisper picture of chemical structure and composition, and to obtain this data quite rapidly. It is also sensitive enough to operate the microscope in a way that allows scientists to study fragile, biological samples without damaging them. Drexel is the first to combine the use of these technologies to give researchers a detailed, clear look at the mechanisms behind chemical and physical reactions almost as quickly as they occur.

NO CEMENT CASTABLE - AN INNOVATIVE SOLUTION FOR ENERGY SAVING FROM HÖGANÄS BJUF AB.

Dr. Sankar Kannabiran and Minghua Zhang
Refractory Research Centre, Höganäs Bjuf AB,  Bjuv, Sweden Tato e-mailová adresa je chráněna před spamboty. Pro její zobrazení musíte mít povolen Javascript.

Abstract:
In industrial conditions, very often, the cost of drying of refractory linings is many folds higher than castable refractories being used as lining materials.  Faster drying of cement bonded refractory castables often leads to explosions due to the  lower permeability that leads to pressure development inside the lining material. There have been several attempts to overcome this issue in industrial conditions. Most of these attempts have focused on replacing calcium aluminate cement by alternative binders such as colloidal silica, liquid phosphates, forsterite etc,.  with potential advantages as well as disadvantages. This work has tried to develop an innovative no cement solid  binder for castable which results in excellent permeability and hence fast drying in nature.

Introducing Emulsion Detonation Synthesis (EDS)

Creating the Next-Generation of Ceramic Powders
 
   There is a huge demand for innovative materials in the ever demanding, high-tech world. Reduced weight, increased durability, greater strength, and improved wear- and temperature-resistance are all highly sought after material characteristics that are desired across a wide range of industries.  With these improved properties comes the ability to: save costs while increasing efficiency; produce coatings, components and devices capable of greater performance; and improve production and manufacturing processes.
  Production processes that allow the design and discovery of novel materials with unique or improved properties are essential to keep driving innovation forward. An example of such a process is Emulsion Detonation Synthesis (EDS) from Innovnano.
  A unique route is provided by this proprietary manufacturing process for the large-scale production of nanostructured ceramic powders, such as aluminum-doped zinc oxide(AZO), monoclinic zirconia and yttria-stabilised zirconia.
  It is also possible to use EDS for the design and development of innovative materials by controlling the precursors used, varying the conditions (example, pressure and temperature), and modifying the kinetics of the reaction.
 


Figure 1. 
Schematic representation of the Emulsion Detonation Synthesis (EDS) method.

Producing Nanostructured Ceramic Powders

  In addition to new and innovative materials, EDS plays a significant role in the production of nanostructured ceramic powders. Innovnano used EDS to develop a variety of powders with improved properties for application in a wide range of industries, such as manufacturing, refractories, and aerospace.
EDS ensures the production of uniform nanostructured ceramics with smaller grain sizes and an even chemical distribution. Therefore, they benefit from resistance to thermal shock, flexural strength and increased hardness, resulting in advanced end-products.
  A range of zirconia powders are available, doped with varied concentrations of yttria (from 0 - 8 mol % yttria stabilized zirconia (YSZ)). The zirconia is fully or partially stabilized by doping the powders with yttria at room temperature, so that its beneficial properties, such as toughness, high bending strength, and hardness can be exploited. All of these properties are improved at a specific yttria content. Close control of dopant concentration by EDS helps to optimize the powder to a particular end application.

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Kalendář

30.05.2018 - 2.06.2018
Ceramics China 2018
Guangzhou/CN
11.06.2018 - 15.06.2018
ACHEMA 2018
Frankfurt/Main
9.07.2018 - 12.07.2018
16.Electroceramics Conference
Hasselt / Belgium
9.10.2018 - 10.10.2018
SUROVINY
Praha/CZ