Analysis of AKS- and lanthana-doped molybdenum wire

Abstract

The lamp industry uses molybdenum wire in many high temperature, structural applications, for which doped molybdenum wire is an important product because it possesses greater high-temperature strength and a higher recrystallization temperature than undoped molybdenum. Prior studies on aluminum–potassium–silicon (AKS) doped tungsten wire have shown that the dispersion which provides the interlocking grain structure in recrystallized tungsten wire is bubbles of elemental potassium; these enhance incandescent lamp filament life. In doped molybdenum the dispersion can be either potassium bubbles, or solid oxide particles, depending on the processing method. Lanthana-doped molybdenum has been reported to have recrystallization temperatures above those obtained through AKS-doping. Lanthana particles are stable within molybdenum to elevated temperatures because lanthanum has very limited solubility in molybdenum. This paper will describe a series of analyses of lanthana-doped and AKS-doped molybdenum wires of a range of sizes.