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Preparation of multiphase materials with spark plasma sintering
Mušálek, Radek; Dlabáček, Zdeněk; Vilémová, Monika; Pala, Zdeněk; Matějíček, Jiří; Chráska, Tomáš
2013 - English
Spark plasma sintering (SPS), also called Field Assisted Sintering Technique (FAST), represents a novel method of preparation of sintered materials from powders. The main advantage of the SPS method is a high achievable heat rate (>200 °C/min) and high sintering temperatures (up to 2200 °C in our laboratory). Combination of high heating rate, rather high pressures (up to 80 MPa) and electric field fluctuations leads to an effective sintering and significant reduction of sintering time for both coarse-grained and nanocrystalline powders. Composite materials may be easily obtained by mixing or layering of different powders. The paper will introduce several examples of multiphase materials sintered by SPS at our institute and the establishment of procedures for routine testing of sub-sized specimens.
Keywords:
spark plasma sintering; powder metallurgy; composites; multiphase materials; FeAl matrix
Available at various institutes of the ASCR
Preparation of multiphase materials with spark plasma sintering
Spark plasma sintering (SPS), also called Field Assisted Sintering Technique (FAST), represents a novel method of preparation of sintered materials from powders. The main advantage of the SPS method ...
Development of large aperture elements for active and adaptive optics
Kmetík, Viliam; Nemcová, S.; Jiran, L.; Stranakova, E.; Inneman, A.
2012 - English
Large-aperture elements for laser active and adaptive optics are investigated in collaboration within IOP AcSci CR, FEng CTU and 5M. A bimorph deformable mirror for high-power lasers based on a lightweight structure with a composite core is currently in development. In order to realize a sufficiently large working aperture we are using new technologies for production of core, bimorph actuator and DM reflector. Detailed simulation of components and structure is validated by measurement and testing. A research of DM actuation and response of a complicated mirror structure needed for an accurate control of a deformation is performed. Testing of samples and subscale measurements are currently performed, measurement of a complete structureis in preparation
Keywords:
laser active and adaptive optics
Available at various institutes of the ASCR
Development of large aperture elements for active and adaptive optics
Large-aperture elements for laser active and adaptive optics are investigated in collaboration within IOP AcSci CR, FEng CTU and 5M. A bimorph deformable mirror for high-power lasers based on a ...
Photonometers for coating and sputtering machines
Oupický, Pavel; Jareš, Daniel; Václavík, Jan; Vápenka, David
2012 - English
The concept of photonometers (alternative name of optical monitor of a vacuum deposition process)for coating and sputtering machines is based on photonometers produced by companies like SATIS or HV Dresden. Photometers were developed in the TOPTEC centre and its predecessor VOD (Optical Development Workshop of Institut of Plasma Physics AS CR) for more than 10 years. The article describes current status of the technology and ideas which will be incorporated in next development steps. Hardware and software used on coating machines B63D, VNA600 and sputtering machine UPM810 is presented.
Keywords:
photonometers
Available at various institutes of the ASCR
Photonometers for coating and sputtering machines
The concept of photonometers (alternative name of optical monitor of a vacuum deposition process)for coating and sputtering machines is based on photonometers produced by companies like SATIS or HV ...
Improving Bond Strenght between Carbon Steel and Plasma Sprayed Ceramics by Phosphating Process
Pokorný, P.; Brožek, Vlastimil; Mastný, L.
2012 - English
Phosphating is currently the highest standard of surface treatment before painting in the vehicle industry. Excluded phosphate crystal layer is due to its high porosity absorbing not only paints but also oil and lubricants that can reliably maintain the surface. Improved bond strenght in the case of coatings exposed in the humid atmospheres in comparison with multiple non-coated surface. Focus of this work is an effort to improve the bond strenght between the diferent plasma-sprayed coatings materials and carbon steel using different phosphate coatings. Because most of the eliminated phosphate crystallizes with four crystal waters the samples was covered by zinc-calcium phosphate, which crystallizes with only two waters [scholzite: Zn2Ca(PO4)2 . 2H2O] and coated from bath of „three-cationts“ phosphate due to the large thickness of the coating and compaction [fosfofylit: Zn2Fe(PO4)2 . 4 H2O]. They decided test for measuring the quality of bond strebght between coating and steel
Keywords:
surface treatments; phosphating coatings; bond strenght; plasma spraying; ceramic coatings
Available at various institutes of the ASCR
Improving Bond Strenght between Carbon Steel and Plasma Sprayed Ceramics by Phosphating Process
Phosphating is currently the highest standard of surface treatment before painting in the vehicle industry. Excluded phosphate crystal layer is due to its high porosity absorbing not only paints but ...
Digital holographic setup for measurement of asymmetric temperature field and tomographic reconstruction
Doleček, Roman; Kopecký, V.; Psota, Pavel; Lédl, Vít
2012 - English
This paper presents a digital holographic multidirectional interferometric method for measurement of periodic asymmetric temperature fields. This method uses a modified Twymann-Green setup having double sensitivity. The setup employs one precisely synchronized and triggered CCD camera with a measured coherent phenomenon. That allows a large number of the phenomenon’s different projections capturing which are used for 3D tomographic reconstruction.
Keywords:
Measurement; asymmetric temperature field; coherent phenomenon; tomographic reconstruction
Available at various institutes of the ASCR
Digital holographic setup for measurement of asymmetric temperature field and tomographic reconstruction
This paper presents a digital holographic multidirectional interferometric method for measurement of periodic asymmetric temperature fields. This method uses a modified Twymann-Green setup having ...
History of development of X-ray optics in Czech Republic
Inneman, A.; Pína, L.; Hudec, René; Černá, D.; Maršíková, V.; Melich, Zbyněk
2012 - English
The summarizing paper sums up more than 40 years of research and development of grazing incidence X-ray optics in the Czech Republic. The origin of astronomical X-ray optics is related to spaceInterkosmos programme Interkosmos. Overall sixty pieces of Wolter I X-ray objectives were manufactured in key cooperation with the Optical Workshop of the Academy of Science in Turnov. Eight of them were used in four different space missions. After the end of Interkosmos project the development of X-ray optics was reoriented to X-ray laboratory tools for crystallography, to Lobster eye systems for wide-angle space monitoring and to Kirkpatrick-Baez imaging system for large X-ray space telescopes. At present, the novel concepts and technologies for X-ray space telescope considered in future ESA, NASA and JAXA missions are being developed
Keywords:
X-ray; Interkosmos; Kirkpatrick-Baez imaging system
Available at various institutes of the ASCR
History of development of X-ray optics in Czech Republic
The summarizing paper sums up more than 40 years of research and development of grazing incidence X-ray optics in the Czech Republic. The origin of astronomical X-ray optics is related to ...
Irregular surfaces - measurements and ZEMAX simulations
Melich, Radek; Psota, Pavel; Lédl, Vít; Václavík, Jan
2012 - English
Surfaces produced on optical elements are loaded by dierent kinds of irregularities whose allowable amplitudes are prescribed by optical tolerances defined by an optical designer. An important feedback between realized and designed surfaces can be achieved using interferometry or profilometry measurements for instance. This article discusses dierent kinds of representation and visualization of those measurements in ZEMAX, enabling optical designer to evaluate an impact of the irregular surface on the optical system performance.
Keywords:
laser; diode-array-radiation; hollow-duct radiation
Available at various institutes of the ASCR
Irregular surfaces - measurements and ZEMAX simulations
Surfaces produced on optical elements are loaded by dierent kinds of irregularities whose allowable amplitudes are prescribed by optical tolerances defined by an optical designer. An important ...
Gallium Phosphide as a material for visible and infrared optics
Václavík, Jan; Vápenka, David
2012 - English
Gallium phosphide is interesting material for optical system working in both visible and MWIR or LWIR spectral ranges. Number of a material available for these applications is limited. They are typically salts, fluorides or sulphides and usually exhibit unfavorable properties like brittleness; softness; solubility in water and small chemical resistance. Although GaP has do not offer best optical parameters excels over most other material in mechanical and chemical resistance. The article describes its most important characteristics and outlines some applications where GaP should prove useful
Keywords:
Gallium phosphide
Available at various institutes of the ASCR
Gallium Phosphide as a material for visible and infrared optics
Gallium phosphide is interesting material for optical system working in both visible and MWIR or LWIR spectral ranges. Number of a material available for these applications is limited. They are ...
Application of pulsed electric field on bacteria and spores
Kadlec, Tomáš; Babický, Václav; Člupek, Martin
2012 - English
Inactivation of bacteria Lactobacilus plantarum, Bacillus subtilis and spores of Bacillus subtilis in conductive aqueous solutions upon application of pulsed electric field was studied.
Keywords:
pulsed electric field; bacteria; water treatment; sterilization
Available at various institutes of the ASCR
Application of pulsed electric field on bacteria and spores
Inactivation of bacteria Lactobacilus plantarum, Bacillus subtilis and spores of Bacillus subtilis in conductive aqueous solutions upon application of pulsed electric field was studied.
Tungsten-Steel Composites and FGMs Produced by Hot Pressing
Matějíček, Jiří; Boldyryeva, Hanna; Brožek, Vlastimil; Čižmárová, E.; Pala, Zdeněk
2012 - English
Tungsten-steel composites and FGMs are being developed for potential application in plasma facing components of fusion devices. In this study, uniform composites and graded layers produced from tungsten and steel powders by hot pressing were investigated. Formation of dense composites with uniform distribution and good bonding of the phases was observed. A thin layer of intermetallic phase Fe7W6 formed at the interfaces. Thermal and mechanical properties of the composites in the as-produced and annealed state were characterized.
Keywords:
FGM; composite; tungsten; steel; fusion reactor material
Available at various institutes of the ASCR
Tungsten-Steel Composites and FGMs Produced by Hot Pressing
Tungsten-steel composites and FGMs are being developed for potential application in plasma facing components of fusion devices. In this study, uniform composites and graded layers produced from ...
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