High Temperature Conductor in Air

Question

I am trying to determine what the best material is for a high temperature conductor. It is for distributing power inside a furnace. I need to run at around 1000 celsius (the furnace is hotter but this is how hot the conductors might get). The lower the resistance, the better. Platinum is not an option for me.

It seems most refractory metals (all besides platinum?) are problematic in the open air with oxidization at these temperatures - even tungsten will rapidly oxidize at 1000C and above. I can coat the wire to protect it, but have not been able to determine what could be reliably used.

Answer 1

The oxide should protect the material for a while- so if your conductors are thick they may last long enough. Nickel superalloys last fairly well, but they have high resistivity, which might be a problem in your application.

If your maximum current is modest, I would suggest a superalloy-clad mineral insulated cable. For example, Hastelloy. Check the manufacturer's data for lifetime estimates.

If you have high voltages, beware that many insulating materials become rather leaky at such temperatures.