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Year 2002 No 3

Ballóková B., Hvizdoš P., Besterci M., Scholl R., Böhm A.
CREEP CHARACTERISTICS OF MOSI2 BASED MATERIALS
Abstract
The creep resistance of two MoSi2 based materials containing SiC and HfO2 particles, respectively, in ambient atmosphere was studied at temperatures 1000 - 1400°C under a stress of 100 MPa. The microstructure and its response to high temperature load were investigated by TEM using thin foil technique. Comparison of the creep resistance of both materials at each particular testing temperature show that the performance of MoSi2 -15 % HfO2 are about one order of magnitude better opposite of MoSi2 - 15 % SiC.
The analysis of the experimental results demonstrate that the creep properties of the both materials (MoSi2 - 15 % HfO2 a MoSi2 - 15 % SiC) confirm relatively good deformation resistance composites during creep testing. The creep resistance of the system MoSi2 - 15 % HfO2 is higher than a creep resistance of the system MoSi2 - 15 % SiC. From the microstructure analysis of the material MoSi2 - HfO2 found, that the structure consists of MoSi2 grains of the matrix (medium-sized ~ 5 ?m), amorphous SiO2 of two kategories (~ 0,5, resp. 1 ?m) and the HfO2 particle (medium-sized 10 resp. 200 nm), which produce clusters mostly on the grain boundary of the matrix. The values of the activation energy (~430 kJ/mol) and analyses of the microstructure demonstrate, that probable majority mechanism of the creep are a diffusion processes.

Keywords: molybdenum disilicide|MoSi2 - SiC and MoSi2 - HfO2|creep behaviour|powder metallurgy|diffusion|
No 3 (2002), p. 235-240
  mag01.pdf (86 kB)
mag01_eng.txt (1 kB)  

Aláčová A., Baláž P.
UTILIZATION OF MECHANICALLY ACTIVATED CALCITE (CaCO3) FOR ZINC SORPTION FROM SOLUTIONS
Keywords: mechanical activation|calcite|sorption|zinc|
No 3 (2002), p. 241-246
mag02_eng.txt (1 kB)  

Kostúr K., Terpák J.
THE HEATING OPTIMISATION WITH SCALE MINIMISATION
Keywords: mathematical model|creating of scale|optimisation|optimal heating trajectories|scale minimisation|
No 3 (2002), p. 247-260
  mag03.pdf (244 kB)
mag03_eng.txt (2 kB)  

Srnka M.
INFLUENCE OF DECARBURISATION REACTION VELOCITY IN EAF ON HYDROGEN AND NITROGEN CONTENT IN STEEL
Keywords: decarburization reaction|nitrogen|hydrogen|steel|
No 3 (2002), p. 261-266
mag04_eng.txt (943 B)  

Plešingerová B., Klapáč M., Kovalčíková M.
GLAZE CRACKING ON THE FIRED POROUS BODY
Keywords: glaze thermal expansion coefficient|glaze stress|crack|Haarriss crack|
No 3 (2002), p. 267-276
mag05_eng.txt (2 kB)  

Omar A.A., Hegazy M.M., Afifi S.E., Abdel Fattah A.
CHARACTERIZATION OF DIFFERENT ELECTROLYTIC IRON POWDERS
Keywords: iron powder|electrolysis|ferrous sulphate|particle size|particle shape|surface texture|apparent density|compressibility|sinterability|
No 3 (2002), p. 277-286
  mag06.pdf (132 kB)
mag06_eng.txt (1 kB)  

Weagová Z., Kucková A., Hudec S., Fröhlichová M.
DUST EMISSIONS FROM ELECTRIC ARC FURNACES AND ITS CONGLOMERATION
Keywords: dust|pellets|mechanical properties of pellets|
No 3 (2002), p. 287-294
  mag07.pdf (240 kB)
mag07_eng.txt (2 kB)  

Bálintová M.
POSSIBILITIES OF THE WEAR CONTAMINATION DECREASING OF THE MILLED SILICON POWDER
Keywords: silicon|milling|wear|contamination|powder purification|
No 3 (2002), p. 295-299
  mag08.pdf (144 kB)
mag08_eng.txt (618 B)  

Cengel P.
KINETICS OF THE STEEL MELTING PROCESS IN THE IRON MELTING
Keywords: steel dissolution|steel dissolution kinetic|
No 3 (2002), p. 300-307
  mag09.pdf (159 kB)
mag09_eng.txt (849 B)  

Kochubey A.A., Syasev A.V., Vesselovskiy V.B., Mamuzych I., Makarenkov E.A., Scherbina E.A.
MATHEMATICAL MODELLING OF METALLURGICAL PROCESSES WITH USAGE OF THE THEORY OF INCREASING BODIES
Keywords: theory of increasing bodies|mathematical model|rolls of hot-rolled steel is conducted|tight strained state|
No 3 (2002), p. 308-320
  mag10.pdf (348 kB)
mag10_eng.txt (476 B)  

Veselovskiy V.B., Kochubey A.A., Syasev A.V., Mamuzych I., Klim E.A.V.G., Syasev V.A.
APPROXIMATE METHODS OF THE SOLUTION OF NON-LINEAR PROBLEMS THERMOMECANICS WITH DRIVING BORDER
Keywords: diphasic bodies|thermoexchange|heat conducting|law of moving of border|
No 3 (2002), p. 321-335
  mag11.pdf (399 kB)
mag11_eng.txt (1 kB)