DPB progress report: Hydrogen uptake capacity for a particular sample of DPB

[摘要] The authors have performed hydrogen uptake to measure the remaining capacity for two DPB pellet samples. The measurements were made with a Cahn microbalance operating at room temperature. The DPB samples were placed inside a quartz boat and the microbalance was then evacuated to a base pressure of 10{sup -4} Torr overnight. This overnight pumping removed volatile contaminants from the DPB pellets prior to the introduction of 600 Torr of N{sub 2} into the microbalance chamber. Next, a leak valve connecting the microbalance with a research grade source of H{sub 2} was opened to add 100 Torr of H{sub 2} on top of the 600 Torr of N{sub 2} already in the microbalance. When the total pressure in the microbalance reached 700 Torr, the H{sub 2} leak valve was not completely shut off but reduced to a very small positive rate. An automatic gate valve connecting the microbalance to a turbo molecular pump was programmed by a controller to keep the total pressure in the microbalance at 700 {+-} 3 Torr. The balance between H{sub 2} consumption due to DPB uptake and H{sub 2} leak rate into the microbalance was such that the gate valve to the turbo molecular pump was only slightly opened by the controller once in a while (a few seconds per few hours) to keep the total pressure constant at 700 Torr.

[发布日期] 2004-11-09 [发布机构] Lawrence Livermore National Laboratory

[关键词] Pumping;Capacity;08 Hydrogen;36 Materials Science;Microbalances