Ultra-high purity tungsten and its applications

High purity (>99.999 wt.%, 5N) or ultra-high purity (>99,9999 wt.%, 6N) tungsten (W) electrodes are vital to the performance and lifetime of high intensity discharge (HID) lamps. On the other hand, alloys based on high purity (>99.99 wt.% or 99.995 wt.%, 4N or 4N5) Ware used as sputtering targets to deposit the films in semiconductor devices. In this study, a highly efficient and cost-saving method for mass producing 6N W powder has been developed. The 5N and 6N W rods and wires for the electrodes of HID lamps have been manufactured by using this powder. In addition, vacuum hot pressing has been employed to prepare 4N5 tungsten-titanium (W-Ti) and 4N tungsten-silicon (W-Si) sputtering targets successfully. The impurities and microstructures of the developed high purity W products have been investigated and are suitable for lighting, semiconductor and photovoltaic applications. (C) 2015 Elsevier Ltd. All rights reserved.