H. Safabinesh, A. Arab Fatideh, M. Navidirad, M. Ghassemi Kakroudi,
Volume 11, Issue 3 (9-2014)
Abstract
In order to improve the corrosion resistance of aluminosilicate refractories by molten aluminum, alkaline
fluoride NaF and cryolite Na3AlF6 powders were studied. Both physical and chemical properties are known to
influence wetting and corrosion behavior. This paper devoted to determine the influence of alkaline fluoride and
cryolite added to andalusite based castable on the reaction with aluminum alloys. These additives led to the in-situ
formation of celsian phases within the refractory matrix that led to improved corrosion resistance at 1300°C. Phase
analysis revealed that celsian formation suppressed the formation of mullite within refractories, thereby reducing
Penetration
M. Heydari Nasab, R. Naghizadeh, H. Samadi, A. Nemati,
Volume 12, Issue 1 (3-2015)
Abstract
Ceramic-matrix composites containing TiC-TiN have been used in a variety of application because of their
superior properties such as high hardness, good wear resistance and high chemical stability. In this research, effect of
coke and coke/calcium beds in synthesis of Al
2O3-Ti(C, N) composites using alumino-carbothermic reduction of TiO
2
has been investigated. Al, TiO
2
and active carbon with additives of extra carbon and NaCl and without additives, in
separate procedures, have been mixed. Afterwards, mixtures were pressed and synthesized in 1200oC for 4hrs, in coke
and coke/calcium beds, separately. Al
2O3-Ti(C,N) composite was synthesized in ternary system of Al-TiO
2
-C with
excess carbon and NaCl additives in calcium/coke bed in 1200 . X-ray diffraction patterns (XRD) results showed that
existence of calcium in bed resulted in intensification of reduction atmosphere in samples and formation of Ti(C,N)
phase enriched from carbon was accelerated. Crystallite sizes of synthesis Ti(C,N) at 1200 °C in reducing conditions
were 22-28 nm.
