RU168280U1 - HETTER DEVICE FOR MOLECULAR HYDROGEN SELECTIVE PUMPING - Google Patents

Abstract

A getter device for the selective pumping of molecular hydrogen from a mixture of gases, including a forming body in the form of a plate or cylinder made of metal and an absorbing layer of palladium covering the entire surface of the hydrogen-binding metal, characterized in that the microparticles of the hydrogen-binding metal are distributed in the volume of the non-porous forming body (matrix) made of palladium metal, which simultaneously absorbs hydrogen.

Description

A device is known, which is a porous getter made of titanium, used to realize two functional properties - decomposition of hydrogen molecules into atoms on the getter surface and chemical strong-energy bonding of hydrogen atoms by the volume of porous titanium metal. A porous titanium getter shows selectivity for hydrogen uptake only at relatively low temperatures. The known device does not fully satisfy the requirements for selectivity of pumping molecular hydrogen due to operation in the temperature range that is technically difficult to use in gas-discharge devices. In this case, with the presence of oxygen-containing components in the medium, the titanium surface is passivated, which leads to a decrease in its sorption characteristics for hydrogen. (Korenovsky NL and others. Composite material based on porous titanium for selective absorption of hydrogen from gas mixtures. University proceedings. ELECTRONICS No. 2 (100), 2013, from 9-16)

Closest to the proposed device is a device for pumping molecular hydrogen containing a forming body of porous titanium, hydrogen bonding in the form of a plate or cylinder, and an absorbing film of palladium deposited on it, and the film of palladium covers the surface of the porous body in its entirety .

In this device, to create the effect of selective pumping out of hydrogen, the titanium surface is modified by applying a palladium film to realize the effect of selective diffusion transparency to hydrogen atoms, which ensures the penetration of a hydrogen flow through the palladium film without chemical bonding, and the required specific sorption capacity of the getter is achieved due to the high-energy chemical bonding of titanium with hydrogen at the palladium-titanium interface. (Korenovsky N.L. et al. Getter device for selective pumping of molecular hydrogen. RF patent for utility model No. 81488. Publ. March 20, 2009 Bull. No. 8)

The disadvantage of this device is the low mechanical strength and ductility of the forming porous material (titanium) even with a thin surface coating of palladium, which does not allow the use of this getter under vibrational loads (up to 10 g).

The development of the proposed device is based on the task of creating an effective selective getter for hydrogen with a high value of specific sorption capacity and at the same time with high strength characteristics.

This problem is solved by creating a getter device for the selective pumping out of molecular hydrogen, including a shaping body in the form of a plate or a cylinder of metal and an absorbing layer of palladium covering the entire surface of the metal that binds hydrogen, characterized in that the microparticles of the metal that binds hydrogen are distributed in a non-porous volume a forming body (matrix) made of palladium metal, which simultaneously absorbs hydrogen.

In a two-layer device, the thermodynamic instability of the palladium-hydrogen system is a positive factor contributing to the creation of a diffusion-transparent medium for hydrogen atoms that penetrate through the palladium layer without chemical bonding and chemically bind to the palladium-hydride-forming metal at the interface.

In the claimed embodiment, we have a dispersed matrix structure of a composite material (in the prototype, a sandwich structure), which is capable of sequentially performing two sorption functions - selectively capture hydrogen atoms from a mixture of gases and effectively bind them in the volume of a hydride-forming metal. In this case, the forming body is a monolithic (in the prototype - porous) matrix of palladium (in the prototype - from hydride-forming titanium), covering the entire surface of the hydride-forming getter microparticles distributed in it with a highly developed surface. Thus, at the same time, we have a dispersion hardened composite material that ensures the mechanical strength of the device.

The selectivity with respect to the bonding of hydrogen atoms occurs in a relatively wide temperature range that is technically suitable for the operation of a gas-discharge device, while atoms of other gases either adsorb on the surface of the membrane (frame) or undergo gas-dynamic reflection from the surface without penetrating into the volume of the membrane metal.

This is achieved by the fact that the proposed device is carried out in several successive technological stages. For example, at the first stage, on the surface of titanium microparticles selected as a hydrogen metal binder, magnetron sputtering under the conditions of a vibro-boiling layer of hydride-forming titanium microparticles is coated with a palladium layer. In the next step, the coated particles are pressed into a specific product shape and sintered under isostatic pressing to form a monolithic palladium matrix with titanium microparticles dispersed in it.

In this case, a composite tape with geometric dimensions was obtained, length 20 mm, thickness 0.2 mm, width 2 mm

Similar operations were carried out with titanium-niobium alloy powder (50/50) to obtain a compact getter device of the above-mentioned geometry.

According to the results of comparative tests of the proposed device and prototype in the same geometric form based on thermogravimetric analysis, a sample of a porous selective getter for hydrogen at 200 ° C and at a hydrogen pressure of 0.1 Pa is characterized by the following parameters of gettering and strength.

Comparative Test Results Suggested device Prototype titanium titanium niobium titanium hydrogen absorption stream (l / s) 5.1 5.7 3.9 maximum specific sorption capacity (m3 Pa / g) 0.3 0.3 0.1 vibration tests samples maintained integrity shedding

From the presented results it follows that the proposed device allows to achieve the goal.

Claims (1)

A getter device for the selective pumping of molecular hydrogen from a gas mixture, including a metal forming body and a palladium absorbing layer covering the surface of the hydrogen binding metal, characterized in that the microparticles of the hydrogen binding metal are distributed in the volume of the non-porous forming body (matrix) made from metallic palladium, simultaneously absorbing hydrogen.

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