Effects of additives on sintering of CVD-MgO powders

The effects of a large number of sintering aids for the densification of magnesia were examined. Al2O3, BaO, Fe2O3, P2O5, SiO2, TiO2, Y2O3 and ZrO2 are effective for the sintering of CVD-MgO powders at low doping levels. The effects of TiO2 and ZrO2 are significant. Heavy doping is harmful for densification. The eight oxides above are also effective for the sintering of seawater MgO, but the degree of effectiveness is smaller than for CVD-MgO. In the doping of BaO, P2O5, SiO2 and TiO2, which form eutectic liquids with MgO below 1600°C, there is an optimum firing temperature for densification. Vickers hardness of doped MgO is proportional to the relative density and is unaffected by doping. Corrosion resistance of MgO ceramics for liquid PbO is also unaffected by dopants, except for P2O5.