James R. Young

Purity of Hydrogen Permeating Through Pd, Pd‐25% Ag, and Ni

Hydrogen permeating Pd and Pd‐25% Ag has been found to have an impurity content as low as a few parts in 1010. A technique is described that allows a determination of the impurity content in hydrogen to be made quite easily.

Palladium‐Diaphragm Hydrogen Pump

It has been found possible to evacuate hydrogen from a container into the air by the use of a heated Pd or PdAg alloy diaphragm. This effect is not the expected diffusion of hydrogen from a region of high hydrogen pressure to a region of lower hydrogen pressure, but a true pumping from a region of low hydrogen concentration to a region of higher hydrogen concentration. This pumping occurs only if the region of higher hydrogen concentration is in an oxidizing atmosphere and the region of lower hydrogen concentration is in a reducing atmosphere or a good vacuum. Pumping speeds for hydrogen up to 0.25 liter/sec per cm2 of diaphragm have been observed for Pd and Pd‐25% Ag alloy 0.004 in. thick while operating between 500 and 600°C. It has been found possible to pump down to a hydrogen pressure of 10−9 mm Hg while the hot Pd diaphragm was exposed to air. Ti and Ni diaphragms were found to exhibit similar pumping characteristics, but much lower pumping speeds were observed.

Ultrahigh Vacuum Leak Sealing Material

A silicon resin GE SR-82 is shown to be capable of sealing metal and glass systems with bakeout temperatures up to 400 deg C and with 10⁻¹⁰ torr. Examples of its use and favorable results are given. (R.E.U.)