波门杜尔铁钴合金（Permendur）是铁钴的软磁合金，其中铁和钴的比例相同，1920年在美国发明。其俄语名称为пермендюр (49К2ФА) 。

标准的波门杜尔铁钴合金称为Fe-Co 50/50或50Fe-50Co，其中最多会含有1%的碳。但1932年有一种已注册的合金，称为Vanadium Permendur及Permendur 2V，最近由Goodfellow公司提供，名称为Permendur 49 （其成份都是49Fe-49Co-2V），含有2%的钒以提升机械性质及加工性。Carpenter科技有生产类似的合金，称为Supermendur及V-Permendur，最近更名为Hiperco 50，最新的成份中，铁、钴、钒的比例不变，但加入了痕量的铌、硅及锰以提升可锻性及冷加工的可加工性。Vacuumschmelze生产了48%...50% 钴合金，名称为VACOFLUX及VACODUR。

Permendur is a cobalt-iron soft magnetic alloy with equal parts of cobalt and iron . The alloy was invented in the United States around 1920 . Standard permendur compositions coined Fe-Co 50/50 or 50Fe-50Co may contain carbon up to 1% while a composition patented in 1932 named Vanadium Permendur, Permendur 2V and recently offered by Goodfellow Corp. under the name Permendur 49 (all of which are 49Fe-49Co-2V) contains 2% vanadium for better mechanical properties and ease of machinability. Carpenter Technologies produced a similar alloy formerly coined Supermendur and 2V-Permendur renamed recently Hiperco 50, and its latest formulation comprises typically same amounts of cobalt, iron and vanadium but with additional trace amounts of niobium, silicon and manganese for even better ease of forgeability and cold forming. Vacuumschmelze produces 48%...50% Cobalt alloys, named VACOFLUX(R) and VACODUR(R). 50Fe-50Co and 49Fe-49Co-2V alloys all have high permeability with little loss and highest flux densities at saturation point (saturation induction is around 23000-24000 Gauss) available amongst commercial soft magnetic alloys. Its magnetic transition temperature is 980 °С . Its name in Russian is пермендюр (49К2ФА).