JPS6167739A - Hydrogen occluding alloy - Google Patents

Abstract

PURPOSE:To obtain a hydrogen occluding alloy enabling the occlusion and release of hydrogen in a medium temp. range by adding a specified percentage of Ca to Ni or further adding other metal. CONSTITUTION:An Ni alloy contg. 11.5-12.0wt% Ca and 0-20wt% one or more among Al, Fe, Mn, Cr, Co and Cu is refined and pulverized to obtain a hydrogen occluding alloy which occludes and releases hydrogen in the medium temp. range of 50-100 deg.C. The alloy occludes a relatively large amount of hydrogen.

Description

[Detailed description of the invention] [Industrial application field] The present invention stores hydrogen in a medium temperature range of 50 to 100°C.

This relates to hydrogen storage alloys that emit hydrogen.

[Conventional technology]

Hydrogen storage alloys are being researched for use in hydrogen storage, transportation, separation, purification, heat pumps, compressors, etc. Among the above-mentioned applications, in applications where thermal energy is exchanged, such as heat pumps and compressors, the mainstream is a system in which two or more types of hydrogen storage alloys are combined and hydrogen is exchanged between the alloys. In the above-mentioned combination of hydrogen storage alloys, it is necessary to have a pressure difference between the alloys to release hydrogen in order to exchange hydrogen between the alloys. It is necessary to combine it with an alloy that releases hydrogen.

Conventionally, MgzNi has been used as this type of hydrogen storage alloy.

FeTi + TiMn1. s*LaNi5 etc. have been developed.

[Problem that the invention seeks to solve]

Among the above alloys, the Mg2Ni alloy has a hydrogen release pressure of several atmospheres at high temperatures around 300°C, and the FeTi
The hydrogen release pressure of alloys, TiMn't, and s alloys is several atmospheres at room temperature. Therefore, MgzNi alloy and FeTi alloy or TiMn1. When combined with s-alloy, a heat source is required to heat the system to around 300°C.

-The LaNi5 alloy exhibits a hydrogen release pressure of several atmospheres at a temperature of several tens of degrees Celsius, so if you combine the LaNi5 alloy with a FeTi alloy or a TiMnt5 alloy, the system can be improved by at most 1
It is sufficient to use a heat source for heating to 00°C. However, the LaNi5 alloy has the disadvantages of being expensive and having a small amount of hydrogen storage per unit weight.

[Failure to solve the problem]

As a means to solve the above conventional problems, the present invention provides Ni
, Ca, Ae, Fe+ Mn l Cr l C
o l It is an alloy consisting of one or more metals selected from the group consisting of Cu, and Ca is 11.5 to 1
Contained in the range of 20% by weight, Al + Fe + 1V
One or more metals selected from the group consisting of Iln + Cr + Co + C'u provide a hydrogen storage alloy in which the content ranges from O to 20% by weight.

CaNi5 alloy has been provided as a hydrogen storage alloy that has a hydrogen release pressure approximately equivalent to that of LaNi5 alloy (Japanese Patent Publication No. 34316/1973), and CaN1x (x = 8.8 to 4.99) has been proposed as a further improvement of this alloy. ) alloy (Special Publication No. 55-35457) or CaN1x (x=3
8-6.3) alloy (Japanese Patent Publication No. 56-33321) is provided. However, as a result of further detailed research by the present inventors on the CaNi-based alloy, the maximum effective hydrogen content of the CaNi-based alloy is not within the above range (Ca is 11.5
They found that it was in the range of 12.0% by weight. By the way, the Ca content in CaNi5 alloy is 12.01
% by weight, CaNi, :r (Z = 8.8~6
3) The alloy has a Ca content of 12.03 to 15.23 tons, which is clearly outside the above range of the present invention.

The CaNi alloy of the present invention further contains An, Fe, Mn.
.

One or more metals selected from the group consisting of Cr, Co, and Cu may be added. The amount of the metal added is limited to 20% by weight or more.

〔experiment〕

In order to clarify the reason for limiting the composition range of the CaNi-based alloy in the present invention, the following experiment will be conducted. A CaNi alloy having a Ca content was produced. The alloy is pulverized and filled into a reaction tube, and hydrogen gas is passed through the reaction tube at 75°C. 1- Pressurize and depressurize the hydrogen scum to be passed through, and use the pressure-volume method to find the C hydrogen pressure car alloy composition cross line, and use the isotherm line to determine the relationship between the effective hydrogen amount and the Ca content in the alloy. I asked for The above relationship is shown in FIG. According to FIG. 1, it is clear that the maximum value of the effective hydrogen amount is in the range of 11.5 to 120% Ca content. □ Experiment 2 ″ In the CaNi alloy, All, Fe '+
' An alloy to which Mn + Cr + Co I Ct + was added was melted in the same manner as in Experiment 1, and 75
℃', and the effective hydrogen amount and release pressure were calculated using the isotherm line. The results are shown in Table 1. □ Table 1 According to Table 1, Al in CaNi alloys.

Alloys A2 to A7 of the present invention, in which the content of Fe + Mn + Cr + 'Co + Cu is up to 20i mass %, show a decrease in discharge pressure, but in terms of effective hydrogen amount, they are abbreviated as alloys AI that do not contain these metals. are equivalent. Also C.

Alloy 8, which contains 20% by weight or more of
It is clear that alloy A9, which contains Ca in a range below the heavy weight plate but above 12.0 weight coefficient, is also inferior to alloys 1 to A7 in terms of effective hydrogen content.

〔effect〕

The hydrogen storage alloy of the present invention has a large effective hydrogen content, with 15
This makes it possible to provide heat pumps and compressors that can operate satisfactorily at temperatures down to 0°C.
Thus, the hydrogen storage alloy of the present invention has a wide range of applications, both industrial and consumer.

[Brief explanation of drawings]

FIG. 1 is a graph in which the horizontal axis represents the Ca content (by weight) of the CaNi alloy and the vertical axis represents the effective hydrogen amount (by weight).

Claims (1)

[Claims] Ni, Ca, Al, Fe, Mn, Cr, Co, Cu
An alloy consisting of one or more metals selected from the group consisting of 11.5 to 12.0% by weight of Ca.
Al, Fe, Mn, Cr, Co, C
A hydrogen storage alloy, characterized in that one or more metals selected from the group consisting of u are contained in a range of 0 to 20% by weight.