Tantalum is one of the refractory metals. Its melting point of 5425°F (2996° C) is exceeded only by tungsten, rhenium and carbon.
Due to its workability, high temperature strength, corrosion resistance, and excellent thermal conductivity, tantalum tubing can be a good choice for thermocouple protection tubes for many applications from room temperature to over 5000°F, depending upon the atmosphere. Continuous operation in air should be limited to a maximum temperature of about 750°F. In vacuum, tantalum can be safely used to 5000°F.