Experience in Improving the Manufacturing Properties of Semifinished Products and Quality of Thoriated Tungsten Products by the Deposition of Tungsten Coatings with WF6 Hydrogen Reduction

Abstract

Tungsten deposition from a gaseous mixture of its hexafluoride with hydrogen on the surface of a porous billet of thoriated tungsten makes it possible to fasten the particles of peripheral layers and its core between each other, as well as to form a more plastic shell on the surface capable of relaxing stresses appearing during rotary forging, thus preventing the destruction of semifinished products. This procedure makes it possible to perform the rotary forging of a pilot batch of insufficiently sintered billets of thoriated tungsten, which would be destroyed if treated uncoated. The improvement of manufacturing properties can be used when fabricating similar tungsten-based compositions (of W(La₂O₃) and W(Y₂O₃)), as well as for other types of deformation. These results can be applicable for (i) lowering the sintering–welding temperature of bars (and rods) of dispersion-strengthened tungsten-based compositions, thereby reducing power consumption and increasing the overhaul period of equipment; (ii) increasing the sizes of semifinished products using the existing equipment thereby increasing the production process productivity and expanding the range of output products; (iii) producing less environmentally hazardous thoriated tungsten products, multiply reducing the radiation exposure of operators; and (iv) using composite cathodes in arc xenon lamps, thereby increasing their service life by a factor of 2–3.