Tantalum targets, tantalum rod manfuacturers should told you these things.

Chemical formula of tantalum niobium ores is AB2O6, both referred to as Ta-Nb ores. A is Fe, Mn, B is niobium, tantalum. Susceptibility of niobium tantalum is (22.1 ~ 37.2) × 10-6. Niobite dielectric coefficient is between 10 and 12, tantalite is 7-8. Mineral density is between 5.15 and 8.20(increased by tantalum content).

Tantalum tube manufacturer should know these things.

Tantalum tube can not be processed by conventional methods as generally metal.Normally the initial step is a forging heat treatment,with a hammer and punch, 2 ways, made tantalum material into small flat slab or circular blank.