چكيده به لاتين
Abstract:
In the present research the effects of zirconim Silicate (ZrSiO4) addition in magnesia-based ceramics in order to initiate reaction sintering will be studied. Magnesia and dolomite based ceramics have numerous applications in steel and cement industries due to their higher melting temperature, however their shortcomings in thermo mechanical and thermo chemical properties have decreased their usage dramatically. Therefore, using appropriate additions is a necessary, For example improving thermal shock behavior, chemical stability and alkali resistance were achieved by zirconia (ZrO2) addition. This addition causes ZrO2 grains distributed uniformly throughout magnesia microstructure, resulting in better fracture toughness and hot strength by crack arresting mechanism. On the other hand, reaction sintering improves magnesia bricks densification which protects Magnesia grains from hydration, better corrosion behavior and improved hot mechanical strength. to overcome magnesia disadvantages, Forsterite (Mg2SiO4) is one of the secondary phases which have been recently attracted attention,which is directly developed by using SiO2 in the form of micro or nano-sized silica additions. It can be synthesized through reaction between magnesia and silica. Forsterite can increase bonding strength of magnesia grains through the reaction sintering,Thus causes great improvements on thermo mechanical properties and thermal shock behavior of Magnesia-based refractories. Higher resistance against alkali slags as well as improvements in refractory properties have been noted in recent studies. The major purpose of this study is to carefully investigate the important factors and effects in cooperated with the addition of zircon (ZrSiO4) and recrystallization of forsterite in a magnesia refractory. Chemical reaction between magnesia and zircon in high temperatures will result in forsterite formation,which improves chemical bonding between magnesia grains. Amount of Zirconia,optimum parameters for forsterite phase formation, microstructural evolution and refractoriness will be given in details. The texture of forsterite bonded magnesia refractory also be monitored and optimum content of Zirconia will be reported.
Keywords: Magnesia; Forsterite; Reaction Sintering; Zircon
