Gas sorbents on the basis of intermetallic compounds and a method for producing the same

Abstract

The present invention relates to new gas sorbents on the basis of intermetallic compounds and a method for producing the same. The method comprises the following steps: mixing and melting of initial metals and homogenization of the melt under negative pressure of inert gas, manufacturing of cast shot by quenching of melted droplets under positive pressure, obtaining of skeleton-type granules by evaporation of the excess of the component A from cast shot under vacuum.

Description

CROSS-REFERENCE TO RELATED APPLICATION [0001] This application claims the priority benefits of U.S. provisional application filed on Apr. 11, 2005, Ser. No. 60 / 670,071. All disclosure of this application is incorporated herein by reference.BACKGROUND OF THE INVENTION [0002] 1. Field of the Invention [0003] The present invention relates to the field of gas sorbents, more precisely of metallic gas sorbents used at room temperature for gas purification and for improvement of vacuum in sealed devices and pumped down chambers. [0004] 2. Description of Related Art [0005] Modern metallic sorbents, also called getters, can be divided conventionally according to their chemical nature into two groups: getters, containing mainly alkaline-earth metals, and getters based on transition metals. The sorption capacity of the former is in average by three orders of magnitude higher than of the latter [J. J. B. Fransen, H. J. R. Perdijk. Vacuum, 10 (1960)199; B. Ferrario. Vacuum, 47 (1996) 363; P. del...

AI Technical Summary

Benefits of technology

The present invention relates to new gas sorbents based on intermetallic compounds with high surface area. The invention provides a method for producing these gas sorbents by melting and homogenizing metals under negative pressure, followed by evaporation of the volatile component. The resulting gas sorbents have a unique structure consisting of a dendritic carcass and an eutectic. The invention also provides an apparatus for carrying out the method. The new gas sorbents have high purity and can be used in various applications.

Problems solved by technology

Vacuum, 47(1996)771], but it turned out that it is technically very difficult to achieve high rates of chemical pumping with the help of active metals like calcium, strontium or barium in spite of the fact that the sticking coefficient of these metals for most important gaseous species is by many times higher than that of the transition metals.

All these methods showed themselves to be of advantage in the case of transitional metals but they are absolutely inapplicable for alkaline-earth metals due to the extremely high reactivity of these metals in the dispersed state.

Independent of the scale of usage of this product, from the technical view point it is not a breakthrough.

In fact, the procedure of crushing an ingot with a pestle and a mortar described in these two patents can not be considered a new technology, and the ability of barium-containing alloys to bind many gases including atmospheric air is well-known [see G. Rocktäschel et al. Z. anorg. allg.

However, experience has shown that the given method has a number of drawbacks:

Argon as quenching medium is more preferable than alkanes, but liquefication of gaseous argon under low pressure in quantities sufficient for quenching several tens of grams of melted metal droplets appeared to be a problem difficult to solve.

This allowed producing small quantities of high purity super active powders in a regime of injection of thin jets of melt but did not provide a possibility to obtain cast shot of diameter 2-3 mm.

Though the properties of the pure powders of alkaline-earth metals obtained by quenching in pure argon are unique, the products are of little use for vacuum applications, and for the time being no methods for their binding into a conglomerate of particles have been developed.

At the same time cast shot of diameter 2-3 mm obtained by quenching in a liquid alkane have limitations in the concentration of an active component, and their specific surface area is not large.

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