IDEA #1LNN2J Two-Layer Pd-W Diffusion Membranes With High Porous W Coating

APPLIED RESEARCH • METALSRESEARCH TWO(cid:2)(cid:2)LAYER PPDD(cid:2)(cid:2)WW DIFFUSION MEMBRANES WITH HIGH POROUS WW COATING Description Diffusion membranes on the base of palladium or its alloys are used for hydrogen input in different experimental devices and technology processes. But they can not be used as plasma facing component due to low Pd erosion resistance. We pro(cid:2) pose two(cid:2)layer Pd(cid:2)W diffusion membrane with high porous W(cid:2) coating on plasma faced side of membrane and vacuum(cid:2)arc (vacuum(cid:2)plasma) technology for such membrane producing to dissolve this problem. From the one hand such membranes have high erosion resistance similar to bulk dense W due to low W erosion coefficient under plasma impact. From the other hand they can provide high hydrogen isotope flows due to W high porosity (up to 50%). In some regimes hydrogen flow value can be near to that for bare Pd membrane. Any damages were not observed after long time repeated thermo cycles. The pilot sample of Pd(cid:2)W diffusion membrane has been developed and installed in the large plasma machine Uragan(cid:2)3M tor(cid:2) satron and has been tested in the edge plasma conditions. It was shown in the test experiments that the membrane tem(cid:2) perature region 673(cid:2)823K and hydrogen pressure of about 0.5(cid:2)1 atm. are enough to provide sufficient hydrogen flows up to 1.5 cm3/s • cm2 into U(cid:2)3M vacuum chamber for hydrogen recycling control both in discharge cleaning and work regimes. Innovative Aspect and Main Advantages Proposed Pd(cid:2)W diffusion membranes combines both high ero(cid:2) sion resistance (e.g., 0.17 atom W per N+ ion with 1.2 keV energy) under plasma impact and high hydrogen isotope per(cid:2) meability near to bare Pd membrane. Such membranes have higher mechanical strength and high radiation(cid:2)damage stabil(cid:2) ity in compare with bare Pd(cid:2)membrane, high thermo cycles resistance. Different configuration variants can be produced: tube, plane, etc. Direct current or indirect heating methods can be used for membrane heating. Areas ooff Application Pd(cid:2)W two(cid:2)layer diffusion membranes were created to meet needs for the scientific and industrial markets. It could be used for active control of hydrogen isotopes recycling and tri(cid:2) tium extraction in thermonuclear fusion devices. It is suitable for different applications when it is needed to input hydrogen isotopes near plasma volume: various plasma machines, plasma chemistry, etc. Fig.1 Pd(cid:2)W diffusion membrane (Pd(cid:2)tube of 6 mm diameter and 200mm length, W(cid:2)coating of 14 μm thickness). 12 Fig. 2. Pd(cid:2)W diffusion membrane (Pd(cid:2)tube of 10 mm diameter and 200 mm length, W(cid:2)coating of 14 μm thickness) in the Uragan(cid:2)3M torsatron. Fig. 3. Hydrogen permeation rate at 973K temperature ver(cid:2) sus pressure for diffusion membranes of 6 mm diameter and 200 mm length: bare palladium (•); high porous 14 μm W film on Pd (•); 4 μm dense VPD W film on Pd (•). Stage ooff Development Pilot sample of the two(cid:2)layer Pd(cid:2)W diffusion membrane with high porous W(cid:2)coating has been produced and installed in plasma machine. This sample has been tested in edge plasma conditions. Contact Details Contact person: Gennadiy Glazunov National Science Center “Kharkov Institute of Physics and Technology” Address: Akademicheskaya str., 1, 61108 Kharkov, Ukraine Tel: (380(cid:2)57) 335 65 71; Fax: (380(cid:2)57) 335 26 64 Mob.: 8(0(cid:2)66)(cid:2)305 38 09 E(cid:2)mail: glazunov@ipp.kharkov.ua