The resulting
superheated steam will dissociate into hydrogen and oxygen on contact with the liquid metal.
The development of this precursor exactly at the interface between the liquid metal and the refractory surface is largely the result of the natural exodus of water vapor in the form of
superheated steam from the refractory.
Herman of the University of Rochester (N.Y.) showed that the lead (111) surface can be substantially
superheated (SN: 9/12/92, p.164).
This creates
superheated steam driving off the hydrogen, leaving oxides to form at the channel.
The
superheated liquid in a bubble chamber is physically quite different from a supersaturated liquid -- in this case, beer saturated with carbon dioxide.
As
superheated molten metal is discharged from the channels, the most severe temperature gradient is created between the refractory hot face and the steel shell cold face.
But ice always melts at 0 [deg.] C; it can't be "
superheated." One possible explanation is that solids begin to melt before they reach their melting points.