The magnesium oxide belongs to the cubic system, the melting point is about 2800℃. The theoretical density is 3．56～3．65g/cm^3, Moh’s hardness is from 5 to 6. Under the high temperature, the resistance value of specific volume is high and has good electrical insulation.
Because the magnesium oxide is easy to volatile when the temperature is in 2300℃, the magnesium oxide ceramics should used in the condition temperature below 2200℃. Due to it has a strong alkali resistance and slagging resistance, the magnesium oxide crucible products manufactured by this special method has a lot of advantages. This kind of product has excellent thermochemical property and resist the metal stability. It can used for smelt nonferrous metals and precious metal, such as platinum, rhodium, iridium and uranium, thorium alloy, iron and other vacuum melting of alloy. What’s more, it can be used for high temperature thermocouple protection tube and the crucible material of high temperature furnace. The magnesium oxide crucible products manufactured by this method also has excellent hydrate resistance property, and can be manufactured in special fields.