... wire, NRC91 or 10% tungsten, 90% tantalum alloy. (or 7.5% tungsten, 90% Ta) Tantaloy Inlet Spring is made of tantaloy "61" metal ... wire, NRC91 or 10% tungsten, 90% tantalum alloy, ... which can provide a lifetime warranteed main regulating spring in the vacuum regulator, tantallum ...