High purity rhenium powder, formed and sintered by carefully selected two-stage reduction of ammonium rhenate, adopts an open pressing mould to ensure that thin rhenium sheet billet with Boson ratio up to 16 can be pressed. After high temperature sintering, the density can reach more than 95% of the theoretical density. Under the condition of strict control of pass deformation, the rhenium sheet with theoretical density of more than 99%, thickness of 0.4mm and size of 320×320mm can be rolled by cold rolling and intermediate annealing process. Compared with the prior art, the invention has the advantages of eliminating the work hardening phenomenon and producing finished rhenium products of different sizes according to the demand.
Metal rhenium with high wear resistance, corrosion resistance, high conductivity, and can maintain high under the condition of high temperature and temperature shock strength and good creep resistance and good thermal performance, often used for emission cathode filament in electronic engineering, kinescope filament, special lamp filament, X - ray target material, high temperature sensor, atomic energy, and many other aspects. In particular, rhenium plays an important role in the rapid development of semiconductor chip production.
However, because of the rapid hardening speed of metal rhenium, its processing, especially deep processing, is difficult. The thermal processing of normally refractory metals is not suitable for rhenium because the rhenium oxide is distributed along the crystal boundaries to form a brittle phase, which cannot be processed.
Usually refractory metals (such as tungsten, molybdenum) are processed at a high temperature of about 150(TC), but the mountain in rhenium in a high temperature without protection atmosphere for processing easy oxidation, and oxide distribution along the grain boundary brittle, can not achieve thermal processing. Therefore, the invention adopts cold rolling processing at room temperature, and strictly controls the amount of pass deformation (8 ~ 15%). Due to work hardening of rhenium speed very fast, even for a time after deformation Hardness multiply rapidly, so the calculation every time after deformation for high temperature annealing treatment in hydrogen (retreat degrees 1500 ~ 1800 ° C, the annealing time is 30 ~ 120 min), make its eliminate the phenomenon of strain hardening and controlled crystallization even close, then rolling for next time. This cycle of processing, heat treatment until reaching the required size, finally after annealing treatment, the finished rhenium sheet.
