Tantalum Rod Research Articles

Electroprecipitation de carbonate d'americycle et de potassium de solutions de carbonate de potassium

Precipitation of potassium americyl carbonate was carried out at multigram scale by oxidizing americium(III) at the platinum anode in 3M K 2CO 3 solutions. Early investigations were conducted on pure americium 241 solutions on the 10 to 40 mg scale, in order to study the different parameters of the electrolysis, and to prove the feasibility of the process. Further experiments were performed on the 20 g scale, in impure americium 241 solutions. Electrolysis performed at 60°C with a platinum grid as the anode, and a tantalum rod immersed in a cathodic compartment, precipitated 20 g of americium 241 with yields above 99% in 2 h. The electroprecipitation process presents the advantage of being clean and suitable for automation techniques in comparison with the chemical oxidation process using potassium persulphate.

Deoxidation of tantalum with liquid calcium

A study has been made of the feasibility of deoxidizing solid tantalum with liquid calcium. The rate of deoxidation of 0.5 cm diameter tantalum rods was measured. As an example, the oxygen content was reduced from 1765 ppm to 100 ppm in 22 hr at 1000°C. The probable rate controlling step is the diffusion of oxygen in tantalum. In extending the study to the deoxidation of sintered and anodized tantalum powder, it was found that the oxygen content could be reduced from 6600 ppm to approximately 300 ppm in a few hours at 1000°C. Capacitors were made from powders deoxidized in calcium without difficulty. The results of electrical property tests on these capacitors are very encouraging.

浮遊帯溶融されたMo, W, Taの二，三の性質

The refining effect of floating zone melting on molybdenum, tungsten and tantalum were investigated from their mechanical properties and chemical analysis. Floating zone melted tungsten and molybdenum rods showed excellent bent ductility at room temperature. By the floating zone melting method, tungsten and molybdenum grew to single crystals rather easily, and their crystal orientations were almost near the (111) direction. By tensile tests, zone melted molybdenum and tantalum rods showed fracturs of the chiseltype break pattern, and no yielding was observed. Compression strain hardening exponents of the floating zone melted molybdenum and tungsten rods were smaller than those of the starting materials, but in the case of the tantalum rod, the strain hardening exponent of the zone melted part was somewhat larger than that of the starting rod. The resistance ratio of the zone melted molybdenum rod was 2.8×10−4 against 4.0×10−2 in the starting rod and 3.2×10−2 in the recrystallization zone.

Interesting Anomaly in the Propagation of 5 Mc Pulses through Tantalum Rod

The propagation of 5 Mc longitudinal waves through tantalum reveals the excitation of a mode having a longitudinal velocity of propagation of 0.052 cm/μsec.