Patent ID: 6129890
Filing Date: 2000-10-10
Classification: B22F,C22B,C22C,H01K

Abstract:
A method of making non-sag tungsten wire comprising the steps of:(a) wet doping tungsten blue oxide with an aqueous solution containing potassium, silicon and aluminum and drying to form a singly doped tungsten blue oxide;(b) dry doping the singly doped tungsten blue oxide with an amount of potassium nitrate to form a double doped tungsten blue oxide;(c) reducing the double doped tungsten blue oxide to form a potassium-doped tungsten metal powder;(d) acid washing the potassium-doped tungsten powder;(e) pressing and sintering the potassium-doped tungsten metal powder to form an ingot; and(f) mechanically working the ingot to form a non-sag tungsten wire having an increased potassium retention compared to the same non-sag tungsten wire produced without the dry doping step (b).