# Does aluminium oxide ionize after melting point?

My chem is very basic but I would like to know is there a temperature after melting point where aluminium oxide can ionize enough to pass electrical current through? Is there a temperature where the resistance of aluminium oxide deteriorates?

I'm going to try and answer a bit of confusion in the original question "Does aluminium oxide ionize after melting point?". Aluminium Oxide is already ionised in the solid, or more pedantically the ionic model fits Aluminium Oxide sufficiently well that we can think of it comprised of $\ce{Al^{3+}}$ and $\ce{O^{2-}}$ ions and make reasonable predictions. The point is that in most solids, ionic or not, the constituent atoms and molecules are energetically constrained to vibrate about their "normal", so called equilibrium, position, and so never move very far, whereas in liquids they can move about reasonably freely. Now as conductivity involves the nett movement of charges most ionic solids are not conducting while the liquids are, as in the liquid the charged ions are free to move toward the appropriate electrode while in the solid they are not.