Microstructure of Free MgO Powder

The aim of this research is to study the Microstructure behavior of pure MgO free (uncompacted) powders and MgO added to magnesium chloride ( ) 2 MgCl free powders with different doping rates (1% , 38% , 44% , and50%) . The sintering temperatures were taken from700 oC to 1600oC in 100 oC steps. The sintering times were taken 3 hr, 24 hr, and 48 hr The essential contribution of this work consists of new results in microstructure development . First , increasing the concentration of magnesium chloride (~50%) led to obtain single ultrafine grains at low temperatures . secondly , the formation of a new structure that is the fiber structure at sintering conditions (temperature and time) ; 1100 oC ,48hr for magnesium oxide added to 44% magnesium chloride powders . while reducing the ratio of the additive material ; magnesium chloride to (~1%) led to decrease the sintering temperature and sintering time to 1000 oC and 3hr , respectively which is required to the fiber formation . An important structure is recognized at the intermediate stage of sintering, this is the Kelvin s tetrakaidecahedron. This occurred at sintering temperature1100 oC , 24 hr sintering time for 44% magnesium chloride added with magnesium oxide powders.