Electrical conductivity of hot-pressed magnesia: Effect of the addition of LiF

The effect of the addition of LiF on the electrical conductivity of hot-pressed magnesia was investigated in the temperature range 200-875°C. The investigated samples had a density higher than 99% of theoretical density. The addition of 1.5-3 wt.% LiF increases the electrical conductivity at 850°C of the as-pressed samples by two orders of magnitude. The electrical conductivity of the as-pressed samples is characterized by an activation energy of 1.2 eV in the temperature range 300-500°C. Heat treatment at 1350°C markedly decreases the electrical conductivity, reducting it the value of pure heat-treated hot-pressed magnesia.