CA1200529A - Raney metal surface electrode with nickel-molybdenum-titanium core - Google Patents
Raney metal surface electrode with nickel-molybdenum-titanium coreInfo
- Publication number
- CA1200529A CA1200529A CA000413568A CA413568A CA1200529A CA 1200529 A CA1200529 A CA 1200529A CA 000413568 A CA000413568 A CA 000413568A CA 413568 A CA413568 A CA 413568A CA 1200529 A CA1200529 A CA 1200529A
- Authority
- CA
- Canada
- Prior art keywords
- percent
- alloy
- raney
- range
- molybdenum
- Prior art date
- 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.)
- Expired
Links
Classifications
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02E—REDUCTION OF GREENHOUSE GAS [GHG] EMISSIONS, RELATED TO ENERGY GENERATION, TRANSMISSION OR DISTRIBUTION
- Y02E60/00—Enabling technologies; Technologies with a potential or indirect contribution to GHG emissions mitigation
- Y02E60/30—Hydrogen technology
- Y02E60/36—Hydrogen production from non-carbon containing sources, e.g. by water electrolysis
Landscapes
- Electrodes For Compound Or Non-Metal Manufacture (AREA)
Abstract
IMPROVED CATHODE FOR CHLOR-ALKALI CELLS
Abstract of the Disclosure An improved cathode with a conductive metal core and a Raney-type catalytic surface predominantly derived from an adherent ternary aluminide intermetallic crystalline precursory outer portion of the metal core is disclosed The precursory outer portion preferably has molybdenum and titanium added to give a precursor alloy having the formula NixMoyTizAl3 where x is within the range of from about 79 to about 94 weight percent, y is within the range of from about 5 to about 20 weight percent and z is within the range of from about 1 to about 5 weight percent of the Ni-Mo-Ti portion of the alloy. Also disclosed is a method of producing a low overvoltage cathode. The method includes the steps of taking a Ni-Mo-Ti core or substrate having about 5-20 weight percentage of Mo and about 1-5 weigh-t percent Ti and coating it with aluminum then heat treating to form a Ni-Mo-Ti-Al ternary alloy with mostly NiAl3 (ordered orthorhombic) crystal structure and then leaching out the Al to produce a ternary NiMoTi alloy Raney surface.
Abstract of the Disclosure An improved cathode with a conductive metal core and a Raney-type catalytic surface predominantly derived from an adherent ternary aluminide intermetallic crystalline precursory outer portion of the metal core is disclosed The precursory outer portion preferably has molybdenum and titanium added to give a precursor alloy having the formula NixMoyTizAl3 where x is within the range of from about 79 to about 94 weight percent, y is within the range of from about 5 to about 20 weight percent and z is within the range of from about 1 to about 5 weight percent of the Ni-Mo-Ti portion of the alloy. Also disclosed is a method of producing a low overvoltage cathode. The method includes the steps of taking a Ni-Mo-Ti core or substrate having about 5-20 weight percentage of Mo and about 1-5 weigh-t percent Ti and coating it with aluminum then heat treating to form a Ni-Mo-Ti-Al ternary alloy with mostly NiAl3 (ordered orthorhombic) crystal structure and then leaching out the Al to produce a ternary NiMoTi alloy Raney surface.
Description
~;~4~5;2~3 RANEY METAL SURFACE ELECTRODE WITH
NICKEL-MOLYBDENUM-TITANIUM CORE
Field of Invention The invention relates to an improved Raneyized hydrogen evolution cathode for chlor-alkali electro-lytic cells.
Prior Art Statement The pertinent prior art has been discussed in great detail in U.S. Patent No. 4,240,895 which has become reissue No. 31,410.
Summary of the Invention One solution is the present invention which pro-vides an improved low overvoltage electrode for use as a hydrogen evolution cathode i.n an electrolytic cell, the electrode being of the type that has a Raney metal surface layer in electrical contact wi-th a conductive metal core, wherein said improvement comprises: said Raney metal surface is predominantly derived from an adherent Ni-Mo-Ti-Al quaternary crystalline precursory outer portion of said metal core.
95'~
Another solution provided by the invention is an improved low overvoltage electrode for use as a hydro-gen evolution cathode in an electrolytic cell, the el-ectrode being of the type that has a Raney metal sur-face layer in electrical contact with a conductive met-al core, wherein the improvement comprises: said Raney metal surface layer is predominantly derived from ad-herent (NixMoyTiz)Al3 crystalline precursory sur~ace layer, where x is within -the range of from about 79 to about 94 weight percent, y is within the range of from about 5 to about 20 weight percent, and z is within the range of from about 1 to about 5 weight percen-t of the Ni-Mo-~i portion of the alloy.
A still further solution provided by the inven-tion is an improved low overvoltage electrode for use in a hydrogen evolution cathode in an electrolytic cell, the electrode being of the type that has a ~aney metal surface layer in electrical contact with a conductive metal core, wherein the improvement comprises: said Raney metal surface is derived from an adherent Ni-Mo-Ti-Al quaternary crystalline intermetallic layer stab-ilized by substitution of a stabilizing amount of moly-bdenum and titanium for some of the nickel in the cry-stalline structure of said crystalline layer.
Yet another solution provided by the invention is a method of producing a low overvoltage electrode for use as a hydrogen evolution cathode in an electrolytic cell which comprises the steps of:
a) coating with aluminum the surface of a clean non-porous conductive base metal structure of an alloy of about 5-20 weight percent molyb-denum, about 1-5 weight percent Ti and 79-94 percent nickel;
b) hea-t treating said coated surface by maintain-ing said surface at a temperature of from 660 to 750C for a time sufficient to diffuse a portion of said aluminum into outer portions of said structure to produce an integral 5~9 nickel-molybdenum-titanium-aluminum alloy layer in said outer portions consisting predominantly of NiA13 type grains but insufficient to create a predominance of Ni2A13 type grainsin said outer portions; and c) leaching out residual aluminum and inter-metallics from the alloy layer until a Raney nickel-molybdenum-titanium layer is formed integral with said structure.
~Brief Description of the Drawing The invention will be better understood by reference to the attached drawing which is provided by way of illustration and in which the FIG~RE is a graph of pol-arization potential versus time for a Raney NiMoTi cathode of the present invention as compared with a Raney NiMo cathode prepared according to the disclosure of U.S. Patent NQ. 4,240,895.
Detailed Description of Preferred Embodiments The FIGURE shows the overpotential curves versus current density for two catalytically coated cathodes, that of the present invention and that of the invention o~.S. Patent Np. 4,240,~5 both prepared similarly from Beta phase precursor. Each has identical percent by weight of molybdenum (12%) and the same method (dipping) of depositing-the aluminum prior to identical heat treatment for two hours at 725C. ~owever; the cathode of the present invention has 2 percent by weight added titanium. The addition of two (2) percent Ti was found to produce, upon subsequent Raney treatment, a ~-Raney Ni-12Mo-2Ti cathode coating having about 50 millivolts less cathode overvoltage than that exhibited by a ~-Raney Ni-12Mo cathode coating. The test me~hod was the same as in U.S. Patent No. 4,240,895~ The reason fox this startling di~ference is no~ known,although the result was confirmed. It is, however, clear that the difference in titanium content was responsible for the difference in potential since all other parameters were held identical.
It is also noted that, as with added molybdenum alone, an unexpected and surprising result is achieved when both molybdenum anc~ titanium are added to a Beta phase (NiA13) intermetallic. The Beta phase formation is stabilized by the addition of molybdenum and titanium in the amount of about 5-20 percent by weight and about 1-5 percent by weight, respectively, of the total weight of nickel, titanium and molybdenum. That is, the titanium does not harm this "Beta-stabilizing"
effect of the molybdenum. Both molybdenum and titanium are apparently captured in the ordered orthorhombic Beta phase crystal structure such that the Beta phase can be represented by the formula NixMoyTizAl3 where x, y, and z are the weight percent nickel, molybdenum and titanium, respectively, in the total weight of nickel, titanium and molybdenum. By "stabilized" is meant that once the seta phase forms it has less of a tendency to transform to a Gamma phase (Ni2A13) crystal structure and thus the elevated heat treatment temperature can last longer without as much undesirable Gamma phase being formed. In fact, the heat treatment at the optimum 725C can last for 2 hours, or 4 hours or even 6 hours with a ~-Raney Ni-Mo-Ti cathode still being produced.
In fact, two hours was used on the samples in the FIGURE.
Since it was shown in the '153 application that the Beta phase is the intermetallic of choice, this is an important advantage of the Ni-Mo-Ti-Al quaternary alloy over Ni-A1 binary alloys.
One preferred electrode is a monolithic structure of a Ni-Mo-Ti alloy of 5-20 percent and most preferably from about 12-18 percent by weight molybdenum and about 80-95 percent and most preferably 82-88 percent by weight nickel with from about 1-5 percent by weight titanium which has heen given a Raney treatment by ~Z~ SZ9 dipping in molten aluminum and heating for about 1-360 minutes in an inert atmosphere at a temperature of from about 660C to about 855C to produce a Beta phase cry-stal structure. A temperature of about 660C to about 750C and a time of about 1-30 or even 5-15 minutes are more preferred because this gives sufficient time for enough aluminum to interdiffuse into the nickel to pro-vide maximum preponderance of NiA13 or Beta phase over Gamma phase (Ni2A13) but does not allow enought time for the diffusion to result in the preponderance of un-desirable Gamma phase (Ni2A13) as is specifically called for in U.S. Patent No~ 4,116,804.
Contrary to the disclosure of U.S. Patent No. 4, 116,804, it has been surprisingly found that the Beta phase NiA13, with molybdenum and titanium added thereto, is not lost during leaching and in fact experiences no appreciable thinning during subsequent use in a chlor-alkali cell.
The inclusion of from about 1 to about 5 percent by weight titanium in the Ni-Mo alloy in order to pro-duce a NiMoTi ternary alloy has given rise to a further surprise in that a further reduction of 50 millivolts overvoltage (at 200 ma/cm2) in cathode overvoltage is achieved. Since the Raney NiMo alloy coating already exhibited such a low overvoltage it is most surprising that any additional lowering occurred from added tit-anium.
Advantageous use can be made of the electrodes of the invention, especially as hydrogen-evolution cathodes of cells intended for the electrolysis of brine, water or the like. The electrodes are particularly preferred for use in brine electrolysis cells, wherein the high electrochemical activity of the ~-Raney nickel-titanium-molybdenum surface remains constant for long periods of extended continuous use. When the electrode is intended for use in a brine-electrolysis diaphragm cell, the di-aphragm can be applied directly to the porous nickel surface of the electrode as noted in U.S~ Patent No.
4,240,895.
. . .
~20~5~
The various parameters associated with the present invention were measured by the techniques described in U.S. Patent No. 4,240,895.
NICKEL-MOLYBDENUM-TITANIUM CORE
Field of Invention The invention relates to an improved Raneyized hydrogen evolution cathode for chlor-alkali electro-lytic cells.
Prior Art Statement The pertinent prior art has been discussed in great detail in U.S. Patent No. 4,240,895 which has become reissue No. 31,410.
Summary of the Invention One solution is the present invention which pro-vides an improved low overvoltage electrode for use as a hydrogen evolution cathode i.n an electrolytic cell, the electrode being of the type that has a Raney metal surface layer in electrical contact wi-th a conductive metal core, wherein said improvement comprises: said Raney metal surface is predominantly derived from an adherent Ni-Mo-Ti-Al quaternary crystalline precursory outer portion of said metal core.
95'~
Another solution provided by the invention is an improved low overvoltage electrode for use as a hydro-gen evolution cathode in an electrolytic cell, the el-ectrode being of the type that has a Raney metal sur-face layer in electrical contact with a conductive met-al core, wherein the improvement comprises: said Raney metal surface layer is predominantly derived from ad-herent (NixMoyTiz)Al3 crystalline precursory sur~ace layer, where x is within -the range of from about 79 to about 94 weight percent, y is within the range of from about 5 to about 20 weight percent, and z is within the range of from about 1 to about 5 weight percen-t of the Ni-Mo-~i portion of the alloy.
A still further solution provided by the inven-tion is an improved low overvoltage electrode for use in a hydrogen evolution cathode in an electrolytic cell, the electrode being of the type that has a ~aney metal surface layer in electrical contact with a conductive metal core, wherein the improvement comprises: said Raney metal surface is derived from an adherent Ni-Mo-Ti-Al quaternary crystalline intermetallic layer stab-ilized by substitution of a stabilizing amount of moly-bdenum and titanium for some of the nickel in the cry-stalline structure of said crystalline layer.
Yet another solution provided by the invention is a method of producing a low overvoltage electrode for use as a hydrogen evolution cathode in an electrolytic cell which comprises the steps of:
a) coating with aluminum the surface of a clean non-porous conductive base metal structure of an alloy of about 5-20 weight percent molyb-denum, about 1-5 weight percent Ti and 79-94 percent nickel;
b) hea-t treating said coated surface by maintain-ing said surface at a temperature of from 660 to 750C for a time sufficient to diffuse a portion of said aluminum into outer portions of said structure to produce an integral 5~9 nickel-molybdenum-titanium-aluminum alloy layer in said outer portions consisting predominantly of NiA13 type grains but insufficient to create a predominance of Ni2A13 type grainsin said outer portions; and c) leaching out residual aluminum and inter-metallics from the alloy layer until a Raney nickel-molybdenum-titanium layer is formed integral with said structure.
~Brief Description of the Drawing The invention will be better understood by reference to the attached drawing which is provided by way of illustration and in which the FIG~RE is a graph of pol-arization potential versus time for a Raney NiMoTi cathode of the present invention as compared with a Raney NiMo cathode prepared according to the disclosure of U.S. Patent NQ. 4,240,895.
Detailed Description of Preferred Embodiments The FIGURE shows the overpotential curves versus current density for two catalytically coated cathodes, that of the present invention and that of the invention o~.S. Patent Np. 4,240,~5 both prepared similarly from Beta phase precursor. Each has identical percent by weight of molybdenum (12%) and the same method (dipping) of depositing-the aluminum prior to identical heat treatment for two hours at 725C. ~owever; the cathode of the present invention has 2 percent by weight added titanium. The addition of two (2) percent Ti was found to produce, upon subsequent Raney treatment, a ~-Raney Ni-12Mo-2Ti cathode coating having about 50 millivolts less cathode overvoltage than that exhibited by a ~-Raney Ni-12Mo cathode coating. The test me~hod was the same as in U.S. Patent No. 4,240,895~ The reason fox this startling di~ference is no~ known,although the result was confirmed. It is, however, clear that the difference in titanium content was responsible for the difference in potential since all other parameters were held identical.
It is also noted that, as with added molybdenum alone, an unexpected and surprising result is achieved when both molybdenum anc~ titanium are added to a Beta phase (NiA13) intermetallic. The Beta phase formation is stabilized by the addition of molybdenum and titanium in the amount of about 5-20 percent by weight and about 1-5 percent by weight, respectively, of the total weight of nickel, titanium and molybdenum. That is, the titanium does not harm this "Beta-stabilizing"
effect of the molybdenum. Both molybdenum and titanium are apparently captured in the ordered orthorhombic Beta phase crystal structure such that the Beta phase can be represented by the formula NixMoyTizAl3 where x, y, and z are the weight percent nickel, molybdenum and titanium, respectively, in the total weight of nickel, titanium and molybdenum. By "stabilized" is meant that once the seta phase forms it has less of a tendency to transform to a Gamma phase (Ni2A13) crystal structure and thus the elevated heat treatment temperature can last longer without as much undesirable Gamma phase being formed. In fact, the heat treatment at the optimum 725C can last for 2 hours, or 4 hours or even 6 hours with a ~-Raney Ni-Mo-Ti cathode still being produced.
In fact, two hours was used on the samples in the FIGURE.
Since it was shown in the '153 application that the Beta phase is the intermetallic of choice, this is an important advantage of the Ni-Mo-Ti-Al quaternary alloy over Ni-A1 binary alloys.
One preferred electrode is a monolithic structure of a Ni-Mo-Ti alloy of 5-20 percent and most preferably from about 12-18 percent by weight molybdenum and about 80-95 percent and most preferably 82-88 percent by weight nickel with from about 1-5 percent by weight titanium which has heen given a Raney treatment by ~Z~ SZ9 dipping in molten aluminum and heating for about 1-360 minutes in an inert atmosphere at a temperature of from about 660C to about 855C to produce a Beta phase cry-stal structure. A temperature of about 660C to about 750C and a time of about 1-30 or even 5-15 minutes are more preferred because this gives sufficient time for enough aluminum to interdiffuse into the nickel to pro-vide maximum preponderance of NiA13 or Beta phase over Gamma phase (Ni2A13) but does not allow enought time for the diffusion to result in the preponderance of un-desirable Gamma phase (Ni2A13) as is specifically called for in U.S. Patent No~ 4,116,804.
Contrary to the disclosure of U.S. Patent No. 4, 116,804, it has been surprisingly found that the Beta phase NiA13, with molybdenum and titanium added thereto, is not lost during leaching and in fact experiences no appreciable thinning during subsequent use in a chlor-alkali cell.
The inclusion of from about 1 to about 5 percent by weight titanium in the Ni-Mo alloy in order to pro-duce a NiMoTi ternary alloy has given rise to a further surprise in that a further reduction of 50 millivolts overvoltage (at 200 ma/cm2) in cathode overvoltage is achieved. Since the Raney NiMo alloy coating already exhibited such a low overvoltage it is most surprising that any additional lowering occurred from added tit-anium.
Advantageous use can be made of the electrodes of the invention, especially as hydrogen-evolution cathodes of cells intended for the electrolysis of brine, water or the like. The electrodes are particularly preferred for use in brine electrolysis cells, wherein the high electrochemical activity of the ~-Raney nickel-titanium-molybdenum surface remains constant for long periods of extended continuous use. When the electrode is intended for use in a brine-electrolysis diaphragm cell, the di-aphragm can be applied directly to the porous nickel surface of the electrode as noted in U.S~ Patent No.
4,240,895.
. . .
~20~5~
The various parameters associated with the present invention were measured by the techniques described in U.S. Patent No. 4,240,895.
Claims (3)
1. An improved low overvoltage electrode for use as a hydrogen evolution cathode in an electro-lytic cell, the electrode being of the type that has a Raney metal surface layer in electrical contact with a conductive metal core, wherein said improve-ment comprises: said Raney metal surface layer is predominantly derived from a monolithic structure having an integral adherent quaternary intermetallic crystalline precursory outer portion of said metal core of the formula (NixMoyTiz)Al3, where x is within the range of from about 79 to about 94 weight percent, y is within the range of from about 5 to about 20 weight percent, and z is within the range of from about 1 to about 5 weight percent of the Ni-Mo-Ti portion of the alloy.
2. The electrode of claim 1 wherein said con-ductive metal core is an alloy containing from about 82 to about 88 percent nickel, from about 12 to about 18 percent molybdenum and from about 1 to about 5 percent titanium.
3. The electrode of claim 1 or 2 wherein the thickness of said Raney metal surface is less than about 7.5 x 10-5 meters (i.e., 75 microns or 3 mils).
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000413568A CA1200529A (en) | 1982-10-15 | 1982-10-15 | Raney metal surface electrode with nickel-molybdenum-titanium core |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CA000413568A CA1200529A (en) | 1982-10-15 | 1982-10-15 | Raney metal surface electrode with nickel-molybdenum-titanium core |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1200529A true CA1200529A (en) | 1986-02-11 |
Family
ID=4123778
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000413568A Expired CA1200529A (en) | 1982-10-15 | 1982-10-15 | Raney metal surface electrode with nickel-molybdenum-titanium core |
Country Status (1)
| Country | Link |
|---|---|
| CA (1) | CA1200529A (en) |
-
1982
- 1982-10-15 CA CA000413568A patent/CA1200529A/en not_active Expired
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US4554176A (en) | Durable electrode for electrolysis and process for production thereof | |
| EP0090425B1 (en) | Electrolysis electrode and production method thereof | |
| US4941953A (en) | Durable electrodes having a plated tinor tin oxide intermediate layer for electrolysis and process for producing the same | |
| US4584084A (en) | Durable electrode for electrolysis and process for production thereof | |
| US4581117A (en) | Durable electrode for electrolysis and process for production thereof | |
| US4162204A (en) | Plated metallic cathode | |
| US4536259A (en) | Cathode having high durability and low hydrogen overvoltage and process for the production thereof | |
| JP2505563B2 (en) | Electrode for electrolysis | |
| US4310391A (en) | Electrolytic gold plating | |
| US4240895A (en) | Raney alloy coated cathode for chlor-alkali cells | |
| JP2505560B2 (en) | Electrode for electrolysis | |
| USRE28820E (en) | Method of making an electrode having a coating containing a platinum metal oxide thereon | |
| JPH0575840B2 (en) | ||
| US4289650A (en) | Cathode for chlor-alkali cells | |
| US5665218A (en) | Method of producing an oxygen generating electrode | |
| Podestá et al. | The influence of iridium, ruthenium and palladium on the electrochemical behaviour of Co-P and Ni-Co-P base amorphous alloys for water electrolysis in KOH aqueous solutions | |
| CA1200529A (en) | Raney metal surface electrode with nickel-molybdenum-titanium core | |
| US4214954A (en) | Plated metallic cathode with porous copper subplating | |
| CN1014726B (en) | Electrolytic metal etching method | |
| US4357227A (en) | Cathode for chlor-alkali cells | |
| JP2528294B2 (en) | Electrode for electrolysis and method of manufacturing the same | |
| JPH0499294A (en) | Oxygen generating anode and its production | |
| JPH02179891A (en) | Anode for generate oxygen and production thereof | |
| JPH0647749B2 (en) | Durable electrode for electrolysis and method of manufacturing the same | |
| US5391280A (en) | Electrolytic electrode and method of production thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry | ||
| MKEX | Expiry |
Effective date: 20030211 |