CA1243491A - Method of manufacturing a hydrogen-storing alloy - Google Patents
Method of manufacturing a hydrogen-storing alloyInfo
- Publication number
- CA1243491A CA1243491A CA000489097A CA489097A CA1243491A CA 1243491 A CA1243491 A CA 1243491A CA 000489097 A CA000489097 A CA 000489097A CA 489097 A CA489097 A CA 489097A CA 1243491 A CA1243491 A CA 1243491A
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- Canada
- Prior art keywords
- melt
- terms
- titanium
- zirconium
- cerium
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- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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Classifications
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- B—PERFORMING OPERATIONS; TRANSPORTING
- B82—NANOTECHNOLOGY
- B82Y—SPECIFIC USES OR APPLICATIONS OF NANOSTRUCTURES; MEASUREMENT OR ANALYSIS OF NANOSTRUCTURES; MANUFACTURE OR TREATMENT OF NANOSTRUCTURES
- B82Y30/00—Nanotechnology for materials or surface science, e.g. nanocomposites
-
- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/02—Making non-ferrous alloys by melting
Abstract
ABSTRACT
The invention relates to a method of manufacturing a hydrogen-storing alloy based on the Laves phases AB2, where A is titanium and/or zirconium, and B is one or more elements from the remainder of the transition metal series, wherewith the ratio of the atomic radii of A and B, rA/rB, is between 1.05 and 1.68. This is run by melting in vacuum or under a protective gas.
In order to achieve maximal hydrogen storing capacity, it is provided according to the invention:
that the melting is carried out in a heating apparatus with a vessel lined with calcium oxide: further, that in a first step a partial alloy is produced comprising the selected elements with the exception of titanium, zirconium, and cerium; that in a second step the partial alloy is deoxidized with titanium and/or zirconium added in an amount of ca. 0.1-0.2 wt.% (of the weight of the entire melt); that in a third step, following a holding time (at temperature) of at least 10 min, the remainder of the prescribed amount of the titanium and/or zirconium is added to the melt; and that the melt is thereafter abruptly cooled.
The invention relates to a method of manufacturing a hydrogen-storing alloy based on the Laves phases AB2, where A is titanium and/or zirconium, and B is one or more elements from the remainder of the transition metal series, wherewith the ratio of the atomic radii of A and B, rA/rB, is between 1.05 and 1.68. This is run by melting in vacuum or under a protective gas.
In order to achieve maximal hydrogen storing capacity, it is provided according to the invention:
that the melting is carried out in a heating apparatus with a vessel lined with calcium oxide: further, that in a first step a partial alloy is produced comprising the selected elements with the exception of titanium, zirconium, and cerium; that in a second step the partial alloy is deoxidized with titanium and/or zirconium added in an amount of ca. 0.1-0.2 wt.% (of the weight of the entire melt); that in a third step, following a holding time (at temperature) of at least 10 min, the remainder of the prescribed amount of the titanium and/or zirconium is added to the melt; and that the melt is thereafter abruptly cooled.
Description
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The invention relates to a method of manufacturing a hydrogen-storing alloy and a hydrogen storing alloy produced by the method.
Hydrogen-storing alloys are composed of intermetallic phases, i.e., chemical compounds of the base components out of which these alloys are made. The stoichiometric ratio of the components are represented adequately by the formula AB2, where A
is an element at or near the beginning of the transition metal series, and B represents one or more elements from the remainder of the transition metal series. A condition which must be satis-fied by A and B is that the ratio of the atomic radii, rA/rB, is between 1.05 and 1.68. Such compounds crystallize in the so-called C14 structure, which is distinguished by an especially dense packing of the atoms. The C14, C15, and C36 structures are designated "Laves phase" structures (for intermetallic compounds).
The elementary (unit) cell of the C14 structure is hexagonal, having 4 A-atoms and 8 B-atoms. The relative density of these metallic, very brittle compounds is about 6 g/cm3.
Numerous examples of such alloys are known from the literature. In addition to titanium and manganese they may be comprised o~, preferably, zirconium, chromium, vanadium, iron, cobalt, nickel, copper, and aluminum (in the appropriate combina-tions). Their "hydrogen storing capacity" is ~ 2 wt.~. The "hydrogen storing capacity" is defined as the difference in weight between the hydrogen uptake at room temperature with hydrogen pressure 50 bar and the hydrogen content at 60 C with a hydrogen pressure of 1 bar, divided by the weight of the storing material.
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German Offenlegungsschrift No. 30 23 77 disclose~ examples of such hydrogen-storing alloys, and a method for the molten metallurgical preparation of these alloys i.e., by smelting. In this method, the powdered components of the alloy are mixed together roughly, and melted in the water-cooled copper crucible of an arc furnace, under vacuum or under a protective gas. The alloy is solidified, comminuted, and remelted in vacuum or under a protective gas, to achieve increased uniformity. These operations may be repeated a number of times.
In order to further improve uniformity, annealing of the hydrogen-storing alloy for several days at 1000C, under vacuum or under a protective gas, has been proposed.
A disadvantage of this known process is that, as a rule, small amounts of oxygen and oxides remain in the hydrogen-storing alloy. These oxygen and oxides appreciably reduce the storing capacity. Further, it is very costly in terms of labor and energy to manufacture the alloy by repeated melting, cooling, and commin-uting, in addition to heat treating. Finally, the melting is often accompanied by reactions between the melt and the crucible material: to counteract this, crucible-free melting methods have been proposed, but these are costly.
It is therefore the object of the invention to provide a method which makes it possible to manufacture hydrogen-storing alloys based on the Laves phases of the formula AB2 with as high a storing capacity as possible and which overcomes the aforesaid disadvantages.
The invention relates to a method of manufacturing a hydrogen-storing alloy and a hydrogen storing alloy produced by the method.
Hydrogen-storing alloys are composed of intermetallic phases, i.e., chemical compounds of the base components out of which these alloys are made. The stoichiometric ratio of the components are represented adequately by the formula AB2, where A
is an element at or near the beginning of the transition metal series, and B represents one or more elements from the remainder of the transition metal series. A condition which must be satis-fied by A and B is that the ratio of the atomic radii, rA/rB, is between 1.05 and 1.68. Such compounds crystallize in the so-called C14 structure, which is distinguished by an especially dense packing of the atoms. The C14, C15, and C36 structures are designated "Laves phase" structures (for intermetallic compounds).
The elementary (unit) cell of the C14 structure is hexagonal, having 4 A-atoms and 8 B-atoms. The relative density of these metallic, very brittle compounds is about 6 g/cm3.
Numerous examples of such alloys are known from the literature. In addition to titanium and manganese they may be comprised o~, preferably, zirconium, chromium, vanadium, iron, cobalt, nickel, copper, and aluminum (in the appropriate combina-tions). Their "hydrogen storing capacity" is ~ 2 wt.~. The "hydrogen storing capacity" is defined as the difference in weight between the hydrogen uptake at room temperature with hydrogen pressure 50 bar and the hydrogen content at 60 C with a hydrogen pressure of 1 bar, divided by the weight of the storing material.
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German Offenlegungsschrift No. 30 23 77 disclose~ examples of such hydrogen-storing alloys, and a method for the molten metallurgical preparation of these alloys i.e., by smelting. In this method, the powdered components of the alloy are mixed together roughly, and melted in the water-cooled copper crucible of an arc furnace, under vacuum or under a protective gas. The alloy is solidified, comminuted, and remelted in vacuum or under a protective gas, to achieve increased uniformity. These operations may be repeated a number of times.
In order to further improve uniformity, annealing of the hydrogen-storing alloy for several days at 1000C, under vacuum or under a protective gas, has been proposed.
A disadvantage of this known process is that, as a rule, small amounts of oxygen and oxides remain in the hydrogen-storing alloy. These oxygen and oxides appreciably reduce the storing capacity. Further, it is very costly in terms of labor and energy to manufacture the alloy by repeated melting, cooling, and commin-uting, in addition to heat treating. Finally, the melting is often accompanied by reactions between the melt and the crucible material: to counteract this, crucible-free melting methods have been proposed, but these are costly.
It is therefore the object of the invention to provide a method which makes it possible to manufacture hydrogen-storing alloys based on the Laves phases of the formula AB2 with as high a storing capacity as possible and which overcomes the aforesaid disadvantages.
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~ , Thus the present invention provides a method for manu-facturing a hydrogen-storing alloy based on the Laves phases AB2, wherein A is titanium or zirconium, and B i9 at least two elements selected from the remainder of the transition metal series, and wherein the ratio of the atomic radii of A and B, rA/rB, is between 1.05 and 1.68, by melting in vacuum or under a protective gas in a heating vessel having a lining made from the oxide or oxides of one or more metals having a strong affinity for oxygen, said method comprising:
a first step, in which a partial alloy is produced by melting elements B comprising the elements selected from the transition metal series with the exception of titanium, zirconium and cerium, if cerium is to be employed as an alloy element;
a second step, in which the partial alloy is deoxidized by adding at least one member selected from the group consisting of titanium, zirconium and aluminum in the amount corresponding to the amount of oxygen introduced in the first step together with the alloy elements;
a third step, in which, following a resting time in which oxide particles resulting from the deoxidation are deposited as completely as possible in the slag, the remainder of the pre-scribed amount of the member selected from the group consistlng of titanium and zirconium is added to the melt; and the said melt is thereafter abruptly cooled.
The present invention also provides a novel hydrogen storing alloy which is made by the above method.
: As component A of the alloy, titanium or zirconium or a ~ _ 3 _ -
~ , Thus the present invention provides a method for manu-facturing a hydrogen-storing alloy based on the Laves phases AB2, wherein A is titanium or zirconium, and B i9 at least two elements selected from the remainder of the transition metal series, and wherein the ratio of the atomic radii of A and B, rA/rB, is between 1.05 and 1.68, by melting in vacuum or under a protective gas in a heating vessel having a lining made from the oxide or oxides of one or more metals having a strong affinity for oxygen, said method comprising:
a first step, in which a partial alloy is produced by melting elements B comprising the elements selected from the transition metal series with the exception of titanium, zirconium and cerium, if cerium is to be employed as an alloy element;
a second step, in which the partial alloy is deoxidized by adding at least one member selected from the group consisting of titanium, zirconium and aluminum in the amount corresponding to the amount of oxygen introduced in the first step together with the alloy elements;
a third step, in which, following a resting time in which oxide particles resulting from the deoxidation are deposited as completely as possible in the slag, the remainder of the pre-scribed amount of the member selected from the group consistlng of titanium and zirconium is added to the melt; and the said melt is thereafter abruptly cooled.
The present invention also provides a novel hydrogen storing alloy which is made by the above method.
: As component A of the alloy, titanium or zirconium or a ~ _ 3 _ -
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mixture thereof may be employed. Titanium alone or in admixture with zirconium i5 preferred.
As component B of the alloy, at least two transition metals which meet the above-described criterion may be employed.
Preferred are vanadium (V), iron (Fe), chromium (Cr), manganese (Mn) and cerium (Ce) and mixtures thereof. In a particularly preferred embodiment, component B comprises all of the above individually named elements.
Where cerium is employed`as an element of the alloy, preferably it is added to the melt resulting from the third step as a final component.
It has been found that it is preferred that the deoxida-tion of the metal (the second step) is carried out in a plurality of partial steps comprising a first partial step in which more than half of the prescribed amount of the deoxidizing agent (that is titanium, zirconium or aluminum) is added.
Examples of the oxides of metals having a high affinity for oxygen, which are used as a lining of the vessel in a heating apparatus according to the present invention, include calcium oxide (CaO), cerium oxide (Ce2O3), zirconium oxide (ZrO2) and aluminum oxide (A12O3), among which preferred is calcium oxide.
One of the essential criteria of the invention is that the hydrogen-storing alloy is manufactured in a heating vessel, e.g. an induction furnace, preferably in a single melting process in which the melt is protected from the outside atmosphere by a vacuum or a protective gas. It is of course also possible to melt together individual alloy constituents beforehand in the form of
mixture thereof may be employed. Titanium alone or in admixture with zirconium i5 preferred.
As component B of the alloy, at least two transition metals which meet the above-described criterion may be employed.
Preferred are vanadium (V), iron (Fe), chromium (Cr), manganese (Mn) and cerium (Ce) and mixtures thereof. In a particularly preferred embodiment, component B comprises all of the above individually named elements.
Where cerium is employed`as an element of the alloy, preferably it is added to the melt resulting from the third step as a final component.
It has been found that it is preferred that the deoxida-tion of the metal (the second step) is carried out in a plurality of partial steps comprising a first partial step in which more than half of the prescribed amount of the deoxidizing agent (that is titanium, zirconium or aluminum) is added.
Examples of the oxides of metals having a high affinity for oxygen, which are used as a lining of the vessel in a heating apparatus according to the present invention, include calcium oxide (CaO), cerium oxide (Ce2O3), zirconium oxide (ZrO2) and aluminum oxide (A12O3), among which preferred is calcium oxide.
One of the essential criteria of the invention is that the hydrogen-storing alloy is manufactured in a heating vessel, e.g. an induction furnace, preferably in a single melting process in which the melt is protected from the outside atmosphere by a vacuum or a protective gas. It is of course also possible to melt together individual alloy constituents beforehand in the form of
- 4 -1243~91 .~ ~
intermediate alloys. In order to prevent reactions o~ the melt with the crucible material, the invention provides that the melt-ing be carried out in a vessel having a lining made of one or more oxides of one or more metals which have a high affinity for oxygen, particularly calcium, cerium, aluminum or zirconium. A
benefit of this is that the melt can be kept molten over a rela~
tively long time without hazard to the vessel, and without large energy losses due to crucible cooling. The choice of lining, moreover, avoids reduction of the vessel lining and thus the otherwisa possible addition of oxygen to the melt despite the presence of the protective gas or vacuum.
The first step of the inventive method is to produce a partial alloy in the melt, using the constituent elements of the ; desired hydrogen-storing alloy with the exception of the pre-scribed amounts of titanium and/or zlrconium and (if any) of cerium. To achieve a uniform intermixing of the components and separation out of any oxide components which may have been intro-duced with the added components, it is recommended that this ; partial alloy be held at a melt temperature for a length of time in terms of minutes which is equal to or exceeds the value in term of centimeters of the bath glass level of the melt.
In a second step, this partial alloy is deoxidized by the addition of at least one metal selected from the group con-sisting of titanium, zirconium and aluminum in an amount corrP-sponding to the amount of oxygen introduced in the first step together with the alloy elements into the melt. This is accom-panied by removing the oxygen amounts still in solution and separ-
intermediate alloys. In order to prevent reactions o~ the melt with the crucible material, the invention provides that the melt-ing be carried out in a vessel having a lining made of one or more oxides of one or more metals which have a high affinity for oxygen, particularly calcium, cerium, aluminum or zirconium. A
benefit of this is that the melt can be kept molten over a rela~
tively long time without hazard to the vessel, and without large energy losses due to crucible cooling. The choice of lining, moreover, avoids reduction of the vessel lining and thus the otherwisa possible addition of oxygen to the melt despite the presence of the protective gas or vacuum.
The first step of the inventive method is to produce a partial alloy in the melt, using the constituent elements of the ; desired hydrogen-storing alloy with the exception of the pre-scribed amounts of titanium and/or zlrconium and (if any) of cerium. To achieve a uniform intermixing of the components and separation out of any oxide components which may have been intro-duced with the added components, it is recommended that this ; partial alloy be held at a melt temperature for a length of time in terms of minutes which is equal to or exceeds the value in term of centimeters of the bath glass level of the melt.
In a second step, this partial alloy is deoxidized by the addition of at least one metal selected from the group con-sisting of titanium, zirconium and aluminum in an amount corrP-sponding to the amount of oxygen introduced in the first step together with the alloy elements into the melt. This is accom-panied by removing the oxygen amounts still in solution and separ-
- 5 -lZ~34''31 ating out the resulting oxide particles. The titanium and/or zirconium are added in these small amounts, rather than in the entire amount also sufficient Eor the alloy content striven Eor, to act as a deoxidizing agent which form relatively large oxide particles which rise rapidly into the slag and are thereby separ-ated out. Fine oxide particles, in contrast, would to a large extent remain in the melt. When using aluminum as the deoxidizing agent it is advisable, since aluminum itself is not an alloy con-stituent, to limit even more the amount added, carrying out only the main portion of the deoxidatlon with aluminum and using titan-ium and/or zirconium for the remaining deoxidation. It is also advantageous to carry out the deoxidation step in more than one partial step, whereby in the first partial step more than half (e.g. 80%) of the prescribed amount of the deoxidizing agent is added.
To make it possible to adequately separate out the oxide particles, the melt must be kept at a melt temperature for a ~ certain time after the addition of the deoxidizing agent. The ; required resting time depends on the type, shape and size of the ; 20 oxide particles as well as on the bath level of the melt (see:
Knuppel - Desoxidation und Vakuumbehandlung von Stahlschmelzen [Deoxidation and Vacuum Treatment of Steel Melts], Dusseldorf, 1970). Good results are achieved if this resting time in terms of minutes is equal to or exceeds the value in terms of centimeters of the bath glass level. Only thereafter is the remaining amount of titanium and/or zirconium added in a third step. It has proven advantageous to also insert a resting period after this for a time
To make it possible to adequately separate out the oxide particles, the melt must be kept at a melt temperature for a ~ certain time after the addition of the deoxidizing agent. The ; required resting time depends on the type, shape and size of the ; 20 oxide particles as well as on the bath level of the melt (see:
Knuppel - Desoxidation und Vakuumbehandlung von Stahlschmelzen [Deoxidation and Vacuum Treatment of Steel Melts], Dusseldorf, 1970). Good results are achieved if this resting time in terms of minutes is equal to or exceeds the value in terms of centimeters of the bath glass level. Only thereafter is the remaining amount of titanium and/or zirconium added in a third step. It has proven advantageous to also insert a resting period after this for a time
6 -1~434~
which in terms of minutes is equal to or exceeds the value in terms of centimeters of the bath glass level.
In a particularly preferred embodiment of the invention, the remaining amount of titan1um and/or zirconium is added in at least two partial amounts, whereby a resting period is added after each addition for a time which in terms of minutes is equal to or exceeds the value of the bath glass level in terms of centimeters.
This promotes uniform composition and further deoxidation of the melt.
Where cerium (generally as cerium misch metal) is em-ployed as an alloy elemen-t,~ lt should be added to the melt after the deoxidation, preferably as the final element, i.e. after the addition of the remaining amount of titanium and/or zirconium, in order to bind any remaining small amounts of oxygen in the melt.
Some of the cerium may be added preliminarily, in order to bind the oxygen present in the melt to cerium, which has the highest affinity for oxygen of any of the components present in the melt.
In this way, already-formed titanium and/or zirconium oxides may be re-reduced.
Cerium oxide has the disadvantage over titanium and/or zirconium oxide that it is denser (relative density ca. 7 g/cm3), and therefore more readily remains in suspension to pervade the hydrogen-storing alloy mass as a detrimental oxide.
To achieve as favourable a crystalline structure as possible, the molten hydrogen-storing alloy should be abruptly cooled in the final step while continuing to shield it ~rom the surrounding air. Preferably, a liquid-cooled metal chill form is
which in terms of minutes is equal to or exceeds the value in terms of centimeters of the bath glass level.
In a particularly preferred embodiment of the invention, the remaining amount of titan1um and/or zirconium is added in at least two partial amounts, whereby a resting period is added after each addition for a time which in terms of minutes is equal to or exceeds the value of the bath glass level in terms of centimeters.
This promotes uniform composition and further deoxidation of the melt.
Where cerium (generally as cerium misch metal) is em-ployed as an alloy elemen-t,~ lt should be added to the melt after the deoxidation, preferably as the final element, i.e. after the addition of the remaining amount of titanium and/or zirconium, in order to bind any remaining small amounts of oxygen in the melt.
Some of the cerium may be added preliminarily, in order to bind the oxygen present in the melt to cerium, which has the highest affinity for oxygen of any of the components present in the melt.
In this way, already-formed titanium and/or zirconium oxides may be re-reduced.
Cerium oxide has the disadvantage over titanium and/or zirconium oxide that it is denser (relative density ca. 7 g/cm3), and therefore more readily remains in suspension to pervade the hydrogen-storing alloy mass as a detrimental oxide.
To achieve as favourable a crystalline structure as possible, the molten hydrogen-storing alloy should be abruptly cooled in the final step while continuing to shield it ~rom the surrounding air. Preferably, a liquid-cooled metal chill form is
- 7 -~%434~1 employed Eor this cooling, for example, a water-cooled steel or copper chill form. It has proven to be advantageous to use the chill forms having an inner surface which is in terms of centi-meters at least to 40 times, preferably 60 times the value in terms o~ kilograms of the melt weight.
Two exemplary embodiments of the invention are given herebelow.
Example 1 A hydrogen-storing alloy with the following composition was desired:
Til.0 V0.4 Feo.07 Cr0,0s Mnl.5 Based on calculatlons of atomlc weights and an expected vapor loss of Mn in an amount of 7.5~, the following formulation was provided for a melt of about 30 kg: Ti = 8.86 kg; V = 3.74 kg;
Fe = 0.71 kg; Cr = 0.48 kg; Mn = 16.27 kg; and Ce (misch metal) =
0.40 kg-In the first step, the prescribed amounts of Fe, Cr, Mn,and V were melted together at 1400C in an induction furnace with a CaO lining and a diameter of 16 cm, under a protective gas. The resulting partial alloy was then deoxidized with 60 g of titanium.
After a waiting time of 20 min, the remainder of the prescribed amount of titanium was added. After an additional 20 min, the prescribed amount of Ce misch metal was added.
Finally, the melt, still under a protective gas, was poured at 1380C into a water-cooled steel mold and abruptly cooled to room temperature. The hydrogen-storing alloy produced had an oxygen content of ~ 0.001 wt.~.
Two exemplary embodiments of the invention are given herebelow.
Example 1 A hydrogen-storing alloy with the following composition was desired:
Til.0 V0.4 Feo.07 Cr0,0s Mnl.5 Based on calculatlons of atomlc weights and an expected vapor loss of Mn in an amount of 7.5~, the following formulation was provided for a melt of about 30 kg: Ti = 8.86 kg; V = 3.74 kg;
Fe = 0.71 kg; Cr = 0.48 kg; Mn = 16.27 kg; and Ce (misch metal) =
0.40 kg-In the first step, the prescribed amounts of Fe, Cr, Mn,and V were melted together at 1400C in an induction furnace with a CaO lining and a diameter of 16 cm, under a protective gas. The resulting partial alloy was then deoxidized with 60 g of titanium.
After a waiting time of 20 min, the remainder of the prescribed amount of titanium was added. After an additional 20 min, the prescribed amount of Ce misch metal was added.
Finally, the melt, still under a protective gas, was poured at 1380C into a water-cooled steel mold and abruptly cooled to room temperature. The hydrogen-storing alloy produced had an oxygen content of ~ 0.001 wt.~.
- 8 -- -1~3~91 Example 2 A hydrogen-storing alloy comprised of Ti, Zr, Fe, Mn, V, and Ce was desired. In the first step, the prescribed amount~ of ~In, V, and ferrovanadium were melted together at 1400C in an induction furnace with a CaO lining, under argon, similarly to Example 1. The melt was held for 30 min at this temperature and then deoxidized with 0.2 wt.% titanium, which was followed by another-30 min holding period. Then about half the prescribed amount of titanium was added, and the melt was held at temperature for 10 min. ~ext, the remainder of the prescribed amount of the titanium, and the zirconium, were added, and the melt was held at temperature for an additional 30 min. Finally, the prescribsd amount of the cerium misch metal was added to the melt, and the resulting melt was tapped at 1380C into a water-cooled mold, where it was cooled.
Again the oxygen content of the alloy was ~ 0.001 wt.%.
In the least favorable case at 0C, the usable hydrogen storing capacity of the alloy was 1.95 wt.% (based on the weight of the alloy3, for a loading pressure of 50 bar and an unloading pressure of 1-2 bar of hydrogen.
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Again the oxygen content of the alloy was ~ 0.001 wt.%.
In the least favorable case at 0C, the usable hydrogen storing capacity of the alloy was 1.95 wt.% (based on the weight of the alloy3, for a loading pressure of 50 bar and an unloading pressure of 1-2 bar of hydrogen.
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Claims (34)
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A method for manufacturing a hydrogen-storing alloy based on the Laves phases AB2, wherein A is titanium or zirconium, and B is one or more elements selected from the remainder of the transition metal series, and the ratio of the atomic radii of A
and B, rA/rB, is between 1.05 and 1.68, by melting in vacuum or under a protective gas in a heating vessel having a lining made from the oxide or oxides of one or more metals having a strong affinity for oxygen, said method comprising:
a first step, in which a partial alloy is produced by melting elements B comprising the elements selected from the transition metal series with the exception of titanium and zircon-ium, and if cerium is to be employed as an alloy element, without cerium;
a second step, in which the partial alloy is deoxidized by adding at least one member selected from the group consisting of titanium, zirconium and aluminum in an amount corresponding to the amount of oxygen introduced in the first step together with the alloy elements, the second step being followed by a rest period in which the oxide particles created by the deoxidation are deposited as completely as possible in the slag;
a third step, in which the remaining quantity of titanium or zirconium is added to the melt; and where cerium is to be used, it is added only after deoxidation and the said melt is thereafter abruptly cooled.
and B, rA/rB, is between 1.05 and 1.68, by melting in vacuum or under a protective gas in a heating vessel having a lining made from the oxide or oxides of one or more metals having a strong affinity for oxygen, said method comprising:
a first step, in which a partial alloy is produced by melting elements B comprising the elements selected from the transition metal series with the exception of titanium and zircon-ium, and if cerium is to be employed as an alloy element, without cerium;
a second step, in which the partial alloy is deoxidized by adding at least one member selected from the group consisting of titanium, zirconium and aluminum in an amount corresponding to the amount of oxygen introduced in the first step together with the alloy elements, the second step being followed by a rest period in which the oxide particles created by the deoxidation are deposited as completely as possible in the slag;
a third step, in which the remaining quantity of titanium or zirconium is added to the melt; and where cerium is to be used, it is added only after deoxidation and the said melt is thereafter abruptly cooled.
2. The method according to claim 1, which further comprises before the abrupt cooling, a fourth step in which cerium is added to the melt as a final alloying component.
3. The method according to claim 1, wherein the deoxidation of the melt is carried out in a plurality of partial steps, com-prising a first partial step in which more than half of the pre-scribed amount of the deoxidizing agent is added.
4. The method according to claim 1, wherein after the addi-tion of the deoxidizing agent the rest period has a length in terms of minutes which is equal to or exceeds the value in terms of centimeters of the bath glass height of the melt.
5. The method according to claim 2 or 3, wherein after the addition of the deoxidizing agent the rest period has a length in terms of minutes which is equal to or exceeds the value in terms of centimeters of the bath glass height of the melt.
6. The method according to claim 1, wherein after the addi-tion of the remaining amount of a member selected from the group consisting of titanium and zirconium, the melt is rested for an additional rest period, the length of which in terms of minutes is equal to or exceeds the value in terms of centimeters of the bath glass level of the melt.
7. The method according to claim 2, 3 or 4, wherein after the addition of the remaining amount of a member selected from the group consisting of titanium and zirconium, the melt is rested for an additional rest period, the length of which in terms of minutes is equal to or exceeds the value in terms of centimeters of the bath glass level of the melt.
8. The method according to claim 1, wherein the remaining quantity of a member selected from the group consisting of titan-ium and zirconium is added in at least two portions, and after the addition of each such portion the melt is rested for a length of time in terms of minutes which is equal to or exceeds the value in terms of centimeters of the bath glass level of the melt.
9. The method according to claim 2 or 3, wherein the remaining quantity of a member selected from the group consisting of titanium and zirconium is added in at least two portions, and after the addition of each such portion the melt is rested for a length of time in terms of minutes which is equal to or exceeds the value in terms of centimeters of the bath glass level of the melt.
10. The method according to claim 4 or 6, wherein the remaining quantity of a member selected from the group consisting of titanium and zirconium is added in at least two portions, and after the addition of each such portion the melt is rested for a length of time in terms of minutes which is equal to or exceeds the value in terms of centimeters of the bath glass level of the melt.
11. The method according to claim 1, 2 or 3, wherein calcium oxide (CaO) is used for the lining.
12. The method according to claim 4, 6 or 8, wherein calcium oxide (CaO) is used for the lining.
13. The method according to claim 1, 2 or 3, wherein cerium oxide (Ce203) is used for the lining.
14. The method according to claim 4, 6 or 3, wherein cerium oxide (Ce203) is used for the lining.
15. The method according to claim 17 2 or 3, wherein zirconium oxide (ZrO2) is used for the lining.
16. The method according to claim 4, 6 or 8, wherein zirconium oxide (ZrO2) is used for the lining.
17. The method according to claim 1, 2 or 3, wherein aluminium oxide (A1203) is used for the lining.
18. The method according to claim 4, 6 or 8, wherein aluminium oxide (A1203) is used for the lining.
19. The method according to claim 1, 2 or 3, wherein the cooling is carried out in a liquid-cooled metal chill form.
20. The method according to claim 4, 6 or 8, wherein the cooling is carried out in a liquid-cooled metal chill form.
21. The method according to claim 1, 2 or 3, wherein the cooling is carried out in a water-cooled steel or copper chill form.
22. The method according to claim 4, 6 or 8, wherein the cooling is carried out in a water-cooled steel or copper chill form.
23. The method according to claim 1, 2 or 3, wherein for the cooling a chill form is used, wherein the chill form has an inner surface in terms of cm2, which is at least 40 times the value in terms of kilograms of the melt weight.
24. The method according to claim 4, 6 or 8, wherein for the cooling a chill form is used, wherein the chill form has an inner surface in terms of cm2, which is at least 40 times the value in terms of kilograms of the melt weight.
25. The method according to claim 1, 2 or 3, wherein for the cooling a chill form is used, wherein the chill form has an inner surface in terms of cm2, which is at least 60 times the value in terms of kilograms of the melt weight.
26. The method according to claim 4, 6 or 8, wherein for the cooling a chill form is used, wherein the chill form has an inner surface in terms of cm2, which is at least 60 times the value in terms of kilograms of the melt weight.
27. The method according to claim 1, 2 or 3, wherein compon-ent B comprises at least two elements selected from the group consisting of vanadium, iron,chromium, manganese and cerium.
28. The method according to claim 1, 2 or 3, wherein compon-ent B comprises vanadium, iron, chromium manganese and cerium wherein AB2 is Til.0 V0.4 Fe0.07Cr0.05Mn1.5
29. The method according to claim 1, 2 or 3, wherein com-ponent A comprises titanium.
30. The method according to claim 1, 2 or 3, wherein com-ponent A comprises titanium and zirconium.
31. The method according to claim 1, 2 or 3, wherein com-ponent B comprises at least two elements selected from the group consisting of vanadium, iron, chromium, manganese and cerium;
calcium oxide (CaO) is used for the lining, and titanium is used as the deoxidizing agent in the second step and as component B
added in the third step.
calcium oxide (CaO) is used for the lining, and titanium is used as the deoxidizing agent in the second step and as component B
added in the third step.
32. The method according to claim 1, 2 or 3, wherein com-ponent B comprises at least two elements selected from the group consisting of vanadium, iron, chromium, manganese and cerium;
calcium oxide (CaO) is used for the lining; titanium is used as the deoxidizing agent in the second step; and titanium and zirconium are added to the melt in the third step.
calcium oxide (CaO) is used for the lining; titanium is used as the deoxidizing agent in the second step; and titanium and zirconium are added to the melt in the third step.
33. A hydrogen-storing alloy based on the Laves phases AB2, wherein A is titanium or zirconium, and B is one or more elements selected from the remainder of the transition metal series, and the ratio of the atomic radii of A and B, rA/rB, is between 1.05 and 1.68, by melting in vacuum or under a protective gas in a heating vessel having a lining made from the oxide or oxides of one or more metals having a strong affinity for oxygen, said alloy being produced by the process of claim 1.
34. The alloy according to claim 33, which contains cerium as element B.
Applications Claiming Priority (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| EP85730075 | 1985-06-05 | ||
| EP85730075.0 | 1985-06-05 | ||
| EP85730105.5 | 1985-08-07 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1243491A true CA1243491A (en) | 1988-10-25 |
Family
ID=8194611
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000489097A Expired CA1243491A (en) | 1985-06-05 | 1985-08-20 | Method of manufacturing a hydrogen-storing alloy |
Country Status (4)
| Country | Link |
|---|---|
| EP (1) | EP0204055B1 (en) |
| JP (1) | JPS61279643A (en) |
| CA (1) | CA1243491A (en) |
| DE (1) | DE3585090D1 (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0210659A (en) * | 1988-06-28 | 1990-01-16 | Matsushita Electric Ind Co Ltd | Manufacture of hydrogen storage alloy |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4079523A (en) * | 1976-11-08 | 1978-03-21 | The International Nickel Company, Inc. | Iron-titanium-mischmetal alloys for hydrogen storage |
| DE3023770C2 (en) * | 1980-06-25 | 1985-08-22 | Daimler-Benz Ag, 7000 Stuttgart | Alloy for storing hydrogen |
-
1985
- 1985-08-07 DE DE8585730105T patent/DE3585090D1/en not_active Expired - Lifetime
- 1985-08-07 EP EP19850730105 patent/EP0204055B1/en not_active Expired - Lifetime
- 1985-08-20 CA CA000489097A patent/CA1243491A/en not_active Expired
- 1985-08-21 JP JP18376485A patent/JPS61279643A/en active Pending
Also Published As
| Publication number | Publication date |
|---|---|
| DE3585090D1 (en) | 1992-02-13 |
| EP0204055A2 (en) | 1986-12-10 |
| EP0204055B1 (en) | 1992-01-02 |
| JPS61279643A (en) | 1986-12-10 |
| EP0204055A3 (en) | 1988-07-27 |
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