Classifications

• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C38/00—Ferrous alloys, e.g. steel alloys
  • C22C38/18—Ferrous alloys, e.g. steel alloys containing chromium
  • C22C38/40—Ferrous alloys, e.g. steel alloys containing chromium with nickel
  • C22C38/50—Ferrous alloys, e.g. steel alloys containing chromium with nickel with titanium or zirconium
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C45/00—Amorphous alloys
  • C22C45/003—Amorphous alloys with one or more of the noble metals as major constituent
• • C—CHEMISTRY; METALLURGY
  • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
  • C25B—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES FOR THE PRODUCTION OF COMPOUNDS OR NON-METALS; APPARATUS THEREFOR
  • C25B11/00—Electrodes; Manufacture thereof not otherwise provided for
  • C25B11/04—Electrodes; Manufacture thereof not otherwise provided for characterised by the material
  • C25B11/051—Electrodes formed of electrocatalysts on a substrate or carrier
  • C25B11/073—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material
  • C25B11/091—Electrodes formed of electrocatalysts on a substrate or carrier characterised by the electrocatalyst material consisting of at least one catalytic element and at least one catalytic compound; consisting of two or more catalytic elements or catalytic compounds

Definitions

• the present invention is directed toward novel amorphous metal alloys which can be considered metallic and are electrically conductive.
• Amorphous metal alloy materials have become of interest in recent years due to their unique combinations of mechanical, chemical and electrical properties which are specially well suited for newly emerging applications.
• Amorphous metal materials have compositionally variable properties, high hardness and strength, flexibility, soft magnetic and ferroelectronic properties, very high resistance to corrosion and wear, unusual alloy compositions, and high resistance to radiation damage. These characteristics are desirable for applic­cations such as low temperature welding alloys, magnetic bubble memories, high field superconducting devices and soft magnetic materials for power transformer cores.
• the amorphous metal alloys of the present invention are particularly useful as electrodes in halogen evolution processes, as set forth in our copending application, U.S. Ser. No. 705,687.
• Other uses as electrodes include the production of fluorine, chlorate, perchlorate, and electrochemical fluorination of organic compounds. These alloys can also be employed as hydrogen permeable membranes.
• amorphous metal alloy materials may be attributed to the disordered atomic structure of amorphous materials which ensures that the material is chemically homogeneous and free from the extended defects that are known to limit the performance of crystalline materials.
• amorphous materials are formed by rapidly cooling the material from a molten state. Such cooling occurs at rates on the order of 106 ° C/second. Processes that provide such cooling rates include sput­tering, vacuum evaporation, plasma spraying and direct quenching from the liquid state. Direct quenching from the liquid state has found the greatest commercial success inasmuch as a variety of alloys are known that can be manu­factured by this technique in various forms such as thin films, ribbons and wires.
• U.S. Pat. No. 3,856,513 describes novel metal alloy compositions obtained by direct quenching from the melt and includes a general discussion of this process.
• the patent describes magnetic amorphous metal alloys formed by subjecting the alloy composition to rapid cooling from a temperature above its melting temperature. A stream of the molten metal was directed into the nip of rotating double rolls maintained at room temperature.
• the quenched metal, obtained in the form of a ribbon was substantially amor­phous as indicated by X-ray diffraction measurements, was ductile, and had a tensile strength of about 350,000 psi (2415 MPa).
• U.S. Pat. No. 4,036,638 describes binary amorphous alloys of iron or cobalt and boron.
• the claimed amorphous alloys were formed by a vacuum melt-casting process wherein molten alloy was ejected through an orifice and against a rotating cylinder in a partial vacuum of about 100 milli­torr. Such amorphous alloys were obtained as continuous ribbons and all exhibited high mechanical hardness and ductility.
• amorphous metal alloys described hereinabove have not been suggested for usage as electrodes in electro­lytic processes in distinction from the alloys utilized for practice of the present invention.
• certain palladium-phosphorus based metal alloys have been prepared and described in U.S. Pat. No. 4,339,270 which discloses a variety of ternary amorphous metal alloys con­sisting of 10 to 40 atomic percent phosphorus and/or silicon and 90 to 60 atomic percent of two or more of palladium, rhodium and platinum.
• Additional elements that can be present include titanium, zirconium, niobium, tantalum and/or iridium.
• the alloys can be used as electrodes for electrolysis and the patent reports high corrosion resis­tance in the electrolysis of halide solutions.
• DSA dimensionally stable anodes
• U.S. Pat. No. 3,234,110 calls for an electrode comprising titanium or a titanium alloy core, coated at least partially with titanium oxide which coating is, in turn, provided with a noble metal coating such as platinum, rhodium, iridium and alloys thereof.
• U.S. Pat. No. 3,236,756 discloses an electrode comprising a titanium core, a porous coating thereon of platinum and/or rhodium and a layer of titanium oxide on the core at the places where the coating is porous.
• U.S. Pat. No. 3,771,385 is directed toward elec­trodes comprising a core of a film forming metal consisting of titanium, tantalum, zirconium, niobium and tungsten, carrying an outside layer of a metal oxide of at least one platinum metal from the group consisting of platinum, iridium, rhodium, palladium, ruthenium and osmium.
• novel amorphous metal alloys are employed as anodes in a process for the electrolysis of halide-containing electrolyte solutions.
• the metal alloys can be binary or ternary, in the former instance certain ternary elements are optional.
• amorphous metal alloys herein refers to amorphous metal-containing alloys that may also comprise one or more of the foregoing non-metallic elements.
• Amor­phous metal alloys may thus include non-metallic elements such as boron, silicon, phosphorus, and carbon.
• Several preferred combinations of elements include Rh/P; Rh/B; Rh/As; Rh/P/B; Rh/B/Pd; Rh/B/Ru and Rh/B/Ti.
• Rh/P Rh/B
• Rh/As Rh/P/B
• Rh/B/Pd Rh/B/Ru and Rh/B/Ti.
• the alloys of the present invention are not palla­dium based, although palladium can be present as a minor component. Moreover, being amorphous, the alloys are not restricted to a particular geometry, or to eutectic composi­tions.
• amorphous metal alloys of the present inven­tion are novel in part because the relative amounts of the component elements are unique.
• Existing amorphous alloys have either not contained the identical elements or have not contained the same atomic percentages thereof. It is believed that the electrochemical activity and corrosion resistance which characterize these alloys are attributable to the unique combination of elements and their respective amounts.
• These alloys can be prepared by any of the stan­dard techniques for fabricating amorphous metal alloys.
• any physical or chemical method such as evaporation, chemical and/or physical decomposition, ion-cluster elec­tron-beam or sputtering process can be utilized.
• the amorphous alloy can be either solid, powder or thin film form, either free standing or attached to a substrate. Trace impurities such as O, N, S, Se, Te and Ar are not expected to be seriously detrimental to the preparation and performance of the materials.
• the only restriction on the environment in which the materials are prepared or operated is that the temperature during both stages be lower than the crystallization temperature of the amorphous metal alloy.
• the amorphous metal alloys of the present inven­tion are particularly suitable as coatings on substrate metals which will ultimately be employed as anodes in various electrochemical processes for the generation of halogens.
• At least one preferred substrate for use as an electrode is titanium although other metals and various non-­metals are also suitable depending upon intended uses.
• the substrate is useful primarily to provide support for the amorphous metal alloys and therefore can also be a non-­conductor or semi-conductor material.
• the coating is readily deposited upon the substrate by sputtering, as is exemplified hereinbelow. Coating thicknesses are not crucial and may range broadly, for example, up to about 100 microns although other thicknesses are not necessarily precluded so long as they are practical for their intended use.
• a useful thickness, exemplified in the work herein­below is 3000 ⁇ .
• a free-­standing or non-supported electrode as prepared by liquid quenching, may have a thickness of approximately 100 microns.
• an amorphous alloy electrode can be prepared by pressing the amorphous alloy, in powder form, into a pre-­determined shape and can also be thick enough to be free-­standing.
• rela­tively thin layers can be deposited and these would be preferably supported by a suitable substrate, as noted hereinabove.
• the actual electrode of the present invention is the amorphous metal alloy whether supported or unsupported. Where a very thin layer is employed, a support may be convenient or even necessary to provide integrity.
• the alloys are substantially amorphous.
• the term "substantially” as used herein in reference to the amorphous metal alloy means that the metal alloys are at least fifty percent amorphous.
• the metal alloy is at least eighty percent amor­phous and most preferably about one hundred percent amor­phous, as indicated by X-ray diffraction analysis.
• the present invention also provides a process for the generation of halogens from halide-containing solutions which employs the novel amorphous metal alloys described herein as anodes.
• a specific reaction that can occur at the anode in the process for chlorine evolution is as follows: 2Cl ⁇ - 2e ⁇ Cl2 Similarly, at the cathode the corresponding reaction can be but is not necessarily limited to: 2H2O + 2e ⁇ H2 + 2OH ⁇
• the amorphous metal alloys employed herein are substantially 100 percent selective to chlorine as compared to about 97 percent for DSA materials. This increased activity has two significant consequences. First, the chlorine evolution efficiency (per unit electrical energy input) is almost 100 percent, an improvement of about 3 percent or better. Second, separation steps may be obviated due to the neglible oxygen content.
• halide-containing solutions can be sub­stituted for sodium chloride such as, for instance, potas­sium chloride, lithium chloride, cesium chloride, hydrogen chloride, iron chloride, zinc chloride, copper chloride and the like.
• Products in addition to chlorine can also include, for instance, chlorates, perchlorates and other chlorine oxides.
• other halides can be present, in lieu of chlorides, and thus, other products generated. The present invention is, therefore, not limited by use in any specific halide-containing solution.
• the process of electrolysis can be conducted at standard conditions known to those skilled in the art. These include temperatures between about 0° to 100° C with about 60° to 90° C being preferred; voltages in the range of from about 1.10 to 1.70 and, current densities of from about 10 to 1000 mA/cm2. Electrolyte solutions (aqueous) are generally at a pH of 1 to 6 and molar concentrations of from about 0.5 to 4M. The cell configuration is not crucial to practice of the process and therefore is not a limitation of the present invention.
• rhodium based amorphous metal alloys were prepared via radio frequency sputtering in argon gas.
• a 2" Research S-Gun, manufactured by Sputtered Films, Inc. was employed.
• DC sputtering can also be employed.
• a titanium substrate was positioned to receive the deposi­tion of the sputtered amorphous alloy. The distance between the target and the substrate in each instance was approxi­mately 10 cm. The composition of each alloy was verified by X-ray analysis and was amorphous thereto.
• the foregoing examples demonstrate the composition and use of novel rhodium based amorphous metal alloys.
• the amor­phous alloys of the present invention have utility as electrodes in various electrochemical processes.
• the superior resistance of other amorphous alloys to corrosion when so employed, has been demonstrated in aforementioned copending patent application, U.S. Ser. No. 705,687, the subject matter of which is incorporated herein by reference. From this it can be extrapolated that electrodes comprising amorphous alloys of the present invention will also be highly resistant to corrosion in electrolytic processes.
• the alloys of this invention were prepared by a sputtering technique which is a useful means for depositing the alloy onto a metal substrate such as titanium, it is to be understood that neither the process of sputtering nor the coating of substrates are to be construed as limitations of the present invention, inasmuch as the alloys can be prepared by other processes and have other forms. Similarly, the composition of the amorphous metal alloys of the present invention can be varied within the scope of the total specification disclosure and therefore neither the particular components nor the relative amounts thereof in the alloys exemplified herein shall be construed as limitations of the invention.
• amorphous metal anodes exemplified herein have been utilized in conjunction with the evolution of chlorine gas from sodium chloride solutions such as brine and sea water
• chlorine gas from sodium chloride solutions
• sodium chloride solutions such as brine and sea water
• other chlorine containing compounds could also be produced via known electrolysis techniques by substituting the amorphous metal anodes of the present invention for the conventional DSA materials of other electrodes.
• other halide-­containing electrolyte solutions could be substituted for the sodium chloride reported herein with a variety of products being obtained.
• these anodes could find utility in any other conventional electroytic cell.

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• Chemical & Material Sciences (AREA)
• Organic Chemistry (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Metallurgy (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Mechanical Engineering (AREA)
• Electrochemistry (AREA)
• Electrodes For Compound Or Non-Metal Manufacture (AREA)
• Electrolytic Production Of Non-Metals, Compounds, Apparatuses Therefor (AREA)
• Inorganic Compounds Of Heavy Metals (AREA)
• Electrolytic Production Of Metals (AREA)
• Secondary Cells (AREA)

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Citations (3)

• 1985
  • 1985-06-23 CN CN198686105607A patent/CN86105607A/zh active Pending
• 1986
  • 1986-06-23 ZA ZA864667A patent/ZA864667B/xx unknown
  • 1986-06-23 NO NO862524A patent/NO862524L/no unknown
  • 1986-06-23 AU AU59197/86A patent/AU5919786A/en not_active Abandoned
  • 1986-06-23 EP EP86304802A patent/EP0209264A1/fr not_active Ceased
  • 1986-06-23 ES ES556440A patent/ES8706852A1/es not_active Expired
  • 1986-06-24 IN IN547/DEL/86A patent/IN171851B/en unknown
  • 1986-06-24 KR KR1019860005044A patent/KR870000445A/ko not_active Application Discontinuation
  • 1986-06-24 BR BR8602910A patent/BR8602910A/pt unknown
  • 1986-06-24 JP JP61147998A patent/JPS6254094A/ja active Pending

Patent Citations (3)

Non-Patent Citations (1)

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