THE EXPERIENCE OF IMPROVING TECHNOLOGICAL PROPERTIES OF SEMI-FINISHED PRODUCTS AND QUALITY OF THORIATED TUNGSTEN PRODUCTS THROUGH DEPOSITION OF TUNGSTEN COATINGS BY WF₆ HYDROGEN REDUCTION

Tungsten deposition from a gaseous mixture of tungsten hexafluoride and hydrogen on the surface of a porous preform made of thoriated tungsten makes it possible to bond particles of peripheral layers and its core against each other, and create more plastic surface coating capable of relaxing stresses occurring during rotary forging, thus preventing destruction of semi-finished products. The described method made it possible to carry out rotary forging of the pilot batch consisting of insufficiently sintered preforms of thoriated tungsten which were previously destroyed if processed uncoated. The achieved improvement of technological properties may be used in the production of similar tungsten-based compositions (grade VL and VI), as well as for other types of deformation. The results can be applicable for the following: 1) Lowering the sintering-welding temperature of bars (and rods) made of dispersion-strengthened tungsten-based compositions, thus reducing power consumption and increasing the time between equipment overhauls; 2) Increasing the size of semi-finished products produced with the existing equipment, thus increasing the process productivity and expanding the range of output products; 3) Releasing less environmentally hazardous thoriated tungsten products, thus greatly reducing radiation exposure of operators; 4) Using composite cathodes in arc xenon lamps, thus increasing their operational life by 2–3 times.

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