Yes, but it's just an inch - and we need a continuous extruded wire at least a dozen meters long. Even on the scale of an inch, thermal expansion coefficient mi

Yes, but it's just an inch - and we need a continuous extruded wire at least a dozen meters long. Even on the scale of an inch, thermal expansion coefficient mismatch problems exist - this was a notorious issue with manufacturability of early vacuum tubes. Turns out it's rather tricky to make glass bond to metal well enough.