US3859176A - Method for making thin film tungsten-thorium alloy - Google Patents

Method for making thin film tungsten-thorium alloy Download PDF

Info

Publication number
US3859176A
US3859176A US335199A US33519973A US3859176A US 3859176 A US3859176 A US 3859176A US 335199 A US335199 A US 335199A US 33519973 A US33519973 A US 33519973A US 3859176 A US3859176 A US 3859176A
Authority
US
United States
Prior art keywords
alloy
substrate
thin film
bath
solution
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 - Lifetime
Application number
US335199A
Other languages
English (en)
Inventor
David C T Shang
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
International Business Machines Corp
Original Assignee
International Business Machines Corp
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by International Business Machines Corp filed Critical International Business Machines Corp
Priority to US335199A priority Critical patent/US3859176A/en
Priority to IT29337/73A priority patent/IT993936B/it
Priority to GB4743973A priority patent/GB1424252A/en
Priority to FR7338165A priority patent/FR2190944B1/fr
Priority to JP48116449A priority patent/JPS49115937A/ja
Priority to CA184,353A priority patent/CA1037414A/fr
Priority to DE2356958A priority patent/DE2356958A1/de
Application granted granted Critical
Publication of US3859176A publication Critical patent/US3859176A/en
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • C—CHEMISTRY; METALLURGY
    • C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
    • C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
    • C25D3/00—Electroplating: Baths therefor
    • C25D3/02—Electroplating: Baths therefor from solutions
    • C25D3/56—Electroplating: Baths therefor from solutions of alloys

Definitions

  • tungstenthorium alloy As wire filaments for incandescent lamps, displays and the like because it can be made in a single crystal state.
  • a thermal compression extruding method is used in the prior art for making these devices. It requires the providing of a powdery mixture of the tungsten and thorium ingredients, concurrently subjecting the mixture to high temperature, circa 2,000C., and high pressure conditions, and extruding the mixture under these conditions through a wire forming die. As such, the extruded wire is in a polycrystal state. In order to make it a single crystal, the wire is subsequently annealed at an elevated temperature, e.g., 1,800C., for approximately 2 hours. As is well known to those skilled in the art, a single crystal tungstenthorium alloy filament has an extended life expectancy as compared to a polycrystal one.
  • the aforedescribed prior art extrusion method is not conducive to making thin film WTh alloys such as thin film plates and sheets, or layers, and particularly thin films of microns or less.
  • it is not conducive to making a thin film WTh alloy in the form of a protective layer or coating used for antithermal, anti-corrosive, and/or wear resistance purposes.
  • this prior art method cannot be employed for making WTh alloy components used in printed and/or integrated circuits.
  • Another object of this invention is to provide a method for making thin film WTh alloys as incandescent filaments.
  • Still another object of this invention is to provide a method of making thin film WTh alloys as components for printed circuits and/or integrated circuits.
  • Still another object of this invention is to provide a method for making thin film WTh alloy bodies and in particular bodies which are substantially planar such as plates or sheets and the like.
  • Another object of this invention is to provide a method for making thin film WTh alloy bodies as a coating or layer for an object and in particular protective coating used for anti-thermal, anti-corrosive and- /or wear resistance purposes.
  • the method for making a thin film tungsten-thorium alloy includes providing a plating bath comprised of a first aqueous solution of W0 NaPO and H 0 at a predetermined temperature.
  • the bath has immersed in it predetermined cathode and anode electrode means.
  • the cathode and anode electrode means are energized to provide a predetermined current density for a predetermined time period.
  • another aqueous solution of a predetermined concentration of Th(SO is added to the bath at a predetermined rate to produce plating of the thin film tungsten-thorium alloy on an appropriate substrate which may be part of the cathode electrode means.
  • FIG. 1 is a perspective view of a member used to apply thereto a thin film WTh alloy according to the method of the present invention
  • FIG. 2 is a perspective view of the WTh alloy layer or coating applied to the member of FIG. 1;
  • FIG. 3 is a perspective view of a thin film W-Th alloy body after the member of FIG. 1 has been removed from the structure of FIG. 2;
  • FIG. 4 is an enlarged partial perspective view of another member useful in applying thereto a WTh alloy according to the method of the present invention
  • FIG. 5 is an enlarged partial front view of the member of FIG. 4 at a different stage of its formation
  • FIG. 6 is an enlarged partial cross-sectional view of the member of FIG. 5 taken along the line 6-6 thereof;
  • FIG. 7 is an enlarged partial cross-sectional view of a thin film WTh alloy filament formed on the member of FIGS. 5 6 according to the method of the present invention.
  • FIG. 8 is an enlarged front view, shown partially in schematic, of a WTh alloy filament display of FIG. 7.
  • the method for making a thin film tungsten-thorium alloy broadly contemplates electrodepositing, i.e., electroplating, a W-Th alloy by passing an electric current through a heated bath consisting essentially of an aqueous solution of W and Na PO and to which is added at a controlled rate a second aqueous solution of Th(SO
  • the aqueous solution of W0 Na PO and H 0 is in the ratio of the order of about 35:l00:200 parts by weight, respectively; a percent concentration of Th(SO is used in the second aqueous solution; and the bath is heated to a temperature of about 80C.
  • the WTh alloy is deposited on a substrate which is immersed in the bath.
  • the substrate is conductive and may be permanent, temporary or partially temporary depending on the particular application.
  • the WTh alloy is to be used as a protective type coating such as a thermal, anti-corrosive and/or anti-abrasive type for an object
  • the object would be immersed in the bath.
  • the object acts as the substrate and is of the permanent type.
  • an WTh alloy body such as WTh sheet it can be deposited on a planar substrate which substrate is subsequently removed by, for example, a suitable etchant or other means. Since the substrate is conductive, it also acts as the cathode electrode of the electroplating system.
  • member 1 is a planar conductive body of, for example, Cu.
  • Asspme for example, it is desired to coat surface la of member 1 with a thin film WTh alloy.
  • An appropriate antiplating masking process is used to mask the opposite surface and edges of member 1.
  • a suitable lead-in conductor is attached to the member 1 in nonobstructing relationship with surface la so that member 1 will also serve as the cathode electrode.
  • the anode electrode, not shown, and cathode electrode are immersed in the aforedescribed heated bath and connected to a suitable electrical supply that passes the plating current through the bath at the same time, i.e., concurrently, the Th(SO aqueoussolution is being added.
  • the WTh alloy coating 2 cf. FIG. 2 is deposited on the surface la of member 1.
  • the member 1 is retained after the electrodepositing such as, for example, the aforementioned applications where the coating 2 is a protective type coating.
  • the member 1 is removed by any suitable means such as etching with a compatible etchant that removes the member 1 without adverse effects to the W--Th alloy.
  • the etchant may, for example, be FeCl
  • the WTh alloy member 2, cf. FIG. 3 becomes an independent body which is substantially rigid and of high strength even at thicknesses of 10 microns or less.
  • the WTh alloy is annealed after the electrodepositing process.
  • One such application is for use of the WTh alloy as an incandescent filament where annealing changes the WTh alloy to a single crystal state.
  • the annealing may be done with or without the member 1 being attached to the WTh alloy film 2.
  • the annealing is done below the melting point of the member 1 when it is attached to the film 2.
  • the annealing temperature may be 900C, for example. If the member 1 is not attached, then the film 2 may be annealed at higher temperatures, e.g., 1,800C.
  • the substrate 3 includes a ceramic planar member 4.
  • a preferred and suitable ceramic for this purpose is A1 0 Imbedded in the ceramic member are an array of conductive posts 5 of a suitable material.
  • posts 5 are high temperature materials such as Au.
  • posts 5 may be of W.
  • the posts 5 may be formed, for example, by drilling holes in the ceramic member 4 at spatial locations corresponding to the desired post array. Next, the insides and around the periphery of the holes so formed are electroplated with gold using well known sensitizing and electroplating techniques.
  • Substrate 3 also includes a conductive layer 6 which is different from the material of the posts 5.
  • the layer 6 is copper. It is formed on the face of the ceramic member 4 by printed circuit deposition techniques. The exposed surface of the layer 6 is co-planar with the end surfaces of the posts 5 which protrude above the front surface 4a, as viewed in FIG. 4. This can be done, for example, by controlling the thickness of the layer 6 during its deposition and/or by subsequent lapping.
  • the copper layer 6 is next processed using well known printed circuit techniques to form a composite conductive pattern 6 made up of individual conductive segments formed between mutually exclusive pairs of posts 5.
  • One such technique which is preferred is to form the pattern using photoresist methods.
  • the composite pattern corresponds to the pattern desired for the WTh alloy filament to be formed on the substrate 3 and more particularly on the members 5, 6 thereof.
  • the pattern 6' comprises a rectangular array of individual segments each of which is square waveshaped in form and only one segment of which is shown in FIGS. 5 and 6 for sake of clarity.
  • a typical array includes 35 such segments arranged in a 5X7 matrix as will be apparent hereinafter.
  • the ends of post 5 protruding outwardly from the rear surface 4b of member 4 are coated with a suitable masking material to prevent depositing of the WTh alloy thereat in the subsequent electroplating, i.e., electrodepositing, process.
  • an aqueous solution of W0 Na PO and B 0 is provided as part of the plating bath.
  • the bath is heated to an elevated temperature of approximately C. Immersed in the bath is the substrate 3 of FIG.
  • the copper segments 6' and gold posts 5 act as the cathode of the electroplating system.
  • a platinum anode is also immersed into the solution and a plating current density of approximately milliamperes per square inch is conducted between the electrodes and through the bath.
  • An appropriate electrical supply is provided for this purpose.
  • a plating time of between 15 to 30 minutes is utilized.
  • an aqueous solution having a concentration of about 10 percent of Th(SO is added to and is part of the plating bath at the rate of approximately 20 drops per minute.
  • the tungsten-thorium alloy film 7 is deposited at the completion of the plating process on the exposed copper pattern 6 and exposed gold end surfaces of the posts 5 of the substrate 3 and thus, has the desired display pattern configuration.
  • an etching process takes place with an etchant that attacks only the conductive segments 6' but does not effect the ceramic member 4, WTh alloy film 7, or posts 5.
  • an etchant such as the aforementioned FeCl is preferred.
  • the film 7 is annealed to place the film 7 in a single crystal state.
  • a temperature is utilized which is below the temperature associated with the material of the members 4, 5 and 7 having the lowest melting point.
  • a suitable annealing temperature is 900C., for example.
  • a preferred way of annealing the W-Th filament pattern 7 is to pass an electrical current through it while it is located in a vacuum or inert atmosphere.
  • the relative high resistance WTh generates heats and incandesces.
  • the WTh is thus at a very high tempera ture which is controlled by the amount of current being passed.
  • the temperature is about 1,800C.
  • the material of posts 5 may have a melting point below this temperature, they will not be adversely affected if they are judiciously selected to have a low resistance, i.e., be a good conductor such as gold, so that the heat generated therein by the current passing through the posts 5 is at a temperature well below their melting point.
  • This operation may be performed prior to mounting the WTh filament pattern 7 in its associated display housing, or alternatively may be preformed after it is mounted in the housing and the housing is evacuated.
  • a suitable printed circuit conductive pattern may be provided on the rear surface 4b of the ceramic member 4 to provide lead-in electrode connections to the individual filament segments located on the front face 4a, cf. FIG. 8.
  • the filament segments via their respective electrode connections are selectively energized to provide the desired character to be read out.
  • the reference numbers 5' indicate the WTh alloy plated end surfaces of the posts 5 for sake of clarity.
  • An example of the plating bath suitable for use in the present method is as follows:
  • the pattern 7 is formed using printed circuit techniques.
  • a conventional photoresist is applied to the exposed surface of the deposited WTh film. Photoresist is exposed through a mask containing the desired conductive display pattern and developed. Thereafter, subsequent etching processes are employed to remove the unwanted portions of the WTh alloy film and to remove the temporary copper layer 6.
  • a mixture of K Fe(Cl ⁇ and NaOH is a suitable etchant for removing the WTh alloy and FeCl is a suitable etchant for removing the copper layer 6.
  • the remaining W-Th filament pattern is annealed to place the WTh alloy in a single crystal state. As a result, a W-Th alloy filament display identical to the one shown in FIGS. 7 8 is provided.
  • the WTh alloy in some applications remains on the object on which it is deposited, cf. FIG. 2. In other applications, it is completely removed from the object, cf. FIG. 3. Still in other applications, it is only partially removed, cf. FIGS. 7 8.
  • said cathode electrode means comprising a substrate on which the WTh film is to be formed

Landscapes

  • Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Electrochemistry (AREA)
  • Materials Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • Electroplating Methods And Accessories (AREA)
  • Electroplating And Plating Baths Therefor (AREA)
  • Manufacturing Of Printed Wiring (AREA)
US335199A 1973-02-23 1973-02-23 Method for making thin film tungsten-thorium alloy Expired - Lifetime US3859176A (en)

Priority Applications (7)

Application Number Priority Date Filing Date Title
US335199A US3859176A (en) 1973-02-23 1973-02-23 Method for making thin film tungsten-thorium alloy
IT29337/73A IT993936B (it) 1973-02-23 1973-09-25 Procedimento per la formazione di leghe a base di tungsteno torio sotto forma di sottili pellicole
GB4743973A GB1424252A (en) 1973-02-23 1973-10-11 Electrolytic method for making thin film tungsten-thorium alloy
FR7338165A FR2190944B1 (fr) 1973-02-23 1973-10-15
JP48116449A JPS49115937A (fr) 1973-02-23 1973-10-18
CA184,353A CA1037414A (fr) 1973-02-23 1973-10-26 Mode de fabrication d'une mince pellicule d'alliage tungtene-thorium
DE2356958A DE2356958A1 (de) 1973-02-23 1973-11-15 Verfahren zum herstellen eines aus einer wolfram-thorium-legierung bestehenden films

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US335199A US3859176A (en) 1973-02-23 1973-02-23 Method for making thin film tungsten-thorium alloy

Publications (1)

Publication Number Publication Date
US3859176A true US3859176A (en) 1975-01-07

Family

ID=23310700

Family Applications (1)

Application Number Title Priority Date Filing Date
US335199A Expired - Lifetime US3859176A (en) 1973-02-23 1973-02-23 Method for making thin film tungsten-thorium alloy

Country Status (7)

Country Link
US (1) US3859176A (fr)
JP (1) JPS49115937A (fr)
CA (1) CA1037414A (fr)
DE (1) DE2356958A1 (fr)
FR (1) FR2190944B1 (fr)
GB (1) GB1424252A (fr)
IT (1) IT993936B (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4218744A (en) * 1978-08-08 1980-08-19 Avicon Development Group Fuel flow consumption monitoring system
US4432839A (en) * 1981-06-18 1984-02-21 Diamond Shamrock Corporation Method for making metallided foils
US6200453B1 (en) * 1997-10-20 2001-03-13 Rajev R. Agarrwal Monolith electroplating process

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB2117957B (en) * 1982-02-22 1986-06-04 British Aerospace Testing of infra-red sensitive equipment

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2160321A (en) * 1936-02-06 1939-05-30 Tungsten Electrodeposit Corp Electrodeposition of tungsten alloys
US2160322A (en) * 1934-09-18 1939-05-30 Tungsten Electrodeposit Corp Electrodeposition of tungsten alloys
US3322653A (en) * 1958-03-17 1967-05-30 Rca Corp Method of making a two sided storage electrode

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2160322A (en) * 1934-09-18 1939-05-30 Tungsten Electrodeposit Corp Electrodeposition of tungsten alloys
US2160321A (en) * 1936-02-06 1939-05-30 Tungsten Electrodeposit Corp Electrodeposition of tungsten alloys
US3322653A (en) * 1958-03-17 1967-05-30 Rca Corp Method of making a two sided storage electrode

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4218744A (en) * 1978-08-08 1980-08-19 Avicon Development Group Fuel flow consumption monitoring system
US4432839A (en) * 1981-06-18 1984-02-21 Diamond Shamrock Corporation Method for making metallided foils
US6200453B1 (en) * 1997-10-20 2001-03-13 Rajev R. Agarrwal Monolith electroplating process

Also Published As

Publication number Publication date
JPS49115937A (fr) 1974-11-06
IT993936B (it) 1975-09-30
FR2190944B1 (fr) 1976-06-18
CA1037414A (fr) 1978-08-29
FR2190944A1 (fr) 1974-02-01
GB1424252A (en) 1976-02-11
DE2356958A1 (de) 1974-08-29

Similar Documents

Publication Publication Date Title
DE3421989C2 (fr)
US7472650B2 (en) Nickel alloy plated structure
DE69735406T2 (de) Glasschaltungssubstrat und Verfahren zu dessen Herstellung
US3801368A (en) Process of electroless plating and article made thereby
FR2459300A1 (fr) Solution pour la metallisation electrochimique de materiaux dielectriques, procede de metallisation electrochimique de materiaux dielectriques au moyen de ladite solution, et materiaux dielectriques traites conformement audit procede
DE3421988A1 (de) Verfahren zum metallisieren von keramischen oberflaechen
US3884771A (en) Process of producing resinous board having a rough surface usable for firmly supporting thereon a printed circuit
US5689227A (en) Circuit board material with barrier layer
DE3631011A1 (de) Flexible schaltungen
US3522085A (en) Article and method for making resistors in printed circuit board
US3901770A (en) Method for the production of microscopically small metal or metal alloy structures
US2793178A (en) Method of providing insulator with multiplicity of conducting elements
US3859176A (en) Method for making thin film tungsten-thorium alloy
US3984290A (en) Method of forming intralayer junctions in a multilayer structure
KR100362866B1 (ko) 반도체장치의 제조방법
US4407860A (en) Process for producing an improved quality electrolessly deposited nickel layer
US3421985A (en) Method of producing semiconductor devices having connecting leads attached thereto
US3540988A (en) Coating method
US2712521A (en) Process of making bismuth resistances
US3679472A (en) Method for bonding a metal pattern to a substrate
EP0423947B1 (fr) Procédé de dépôt électrolytique sur des polymères électroactifs et articles obtenus avec ce procédé
US3392053A (en) Memory fabrication method
US4382977A (en) Method of producing smooth metallic layers on a substrate
US3292164A (en) Coating product
US3514379A (en) Electrodeposition of metals on selected areas of a base