Neil Gerace wrote:
Pat Flannery wrote:

Okay, I'm in 166 pages so far... and _this_ is interesting.
The fact that the titanium would actually _burn_ and not just melt
was very unexpected.

Titanium is in fact one of the more reactive metals. It can be used as
a structural metal (unlike e.g. sodium) because any cut face reacts
quickly with atmospheric oxygen. The oxide layer is tightly bound to
the metal underneath. This prevents oxygen from further attacking the
metal. Same thing happens with aluminium. It also happens with iron,
but in that case the oxide doesn't bond very strongly with the metal,
allowing oxygen to further corrode it.

Check up on my later posting regrading when the aluminum versus titanium
ignited when the Columbia orbiter broke apart.
Surprisingly, it was the titanium, not aluminum, that first ignited
after the whole orbiter first started going to pieces.

Pat