US3906617A - Method of preventing braze and diffusion flow - Google Patents
Method of preventing braze and diffusion flow Download PDFInfo
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- US3906617A US3906617A US141351A US14135171A US3906617A US 3906617 A US3906617 A US 3906617A US 141351 A US141351 A US 141351A US 14135171 A US14135171 A US 14135171A US 3906617 A US3906617 A US 3906617A
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- 238000000034 method Methods 0.000 title claims description 12
- 238000009792 diffusion process Methods 0.000 title abstract description 29
- 239000000203 mixture Substances 0.000 claims abstract description 27
- 229910052761 rare earth metal Inorganic materials 0.000 claims abstract description 23
- -1 rare earth compound Chemical class 0.000 claims abstract description 19
- 239000011343 solid material Substances 0.000 claims abstract description 15
- 239000000725 suspension Substances 0.000 claims abstract description 9
- 229910044991 metal oxide Inorganic materials 0.000 claims abstract description 8
- 150000004706 metal oxides Chemical class 0.000 claims abstract description 8
- 238000005219 brazing Methods 0.000 claims description 16
- 239000000956 alloy Substances 0.000 claims description 14
- 229910045601 alloy Inorganic materials 0.000 claims description 14
- 239000000945 filler Substances 0.000 claims description 13
- 229910001404 rare earth metal oxide Inorganic materials 0.000 claims description 6
- 239000002253 acid Substances 0.000 claims description 4
- 150000007513 acids Chemical class 0.000 claims description 4
- 230000001680 brushing effect Effects 0.000 claims description 4
- 229910052500 inorganic mineral Inorganic materials 0.000 claims description 3
- 239000011707 mineral Substances 0.000 claims description 3
- 150000002910 rare earth metals Chemical class 0.000 claims description 3
- 239000000463 material Substances 0.000 abstract description 7
- 239000003870 refractory metal Substances 0.000 abstract description 7
- 150000001875 compounds Chemical class 0.000 abstract description 5
- 238000007796 conventional method Methods 0.000 abstract description 3
- 238000000576 coating method Methods 0.000 description 28
- 239000011248 coating agent Substances 0.000 description 24
- SIWVEOZUMHYXCS-UHFFFAOYSA-N oxo(oxoyttriooxy)yttrium Chemical compound O=[Y]O[Y]=O SIWVEOZUMHYXCS-UHFFFAOYSA-N 0.000 description 10
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 8
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N Titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 7
- 229920002689 polyvinyl acetate Polymers 0.000 description 5
- 239000004744 fabric Substances 0.000 description 4
- 239000004922 lacquer Substances 0.000 description 4
- 229910052751 metal Inorganic materials 0.000 description 4
- 239000002184 metal Substances 0.000 description 4
- 229910052727 yttrium Inorganic materials 0.000 description 4
- VWQVUPCCIRVNHF-UHFFFAOYSA-N yttrium atom Chemical compound [Y] VWQVUPCCIRVNHF-UHFFFAOYSA-N 0.000 description 4
- 125000001931 aliphatic group Chemical group 0.000 description 3
- 239000011118 polyvinyl acetate Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- OGIDPMRJRNCKJF-UHFFFAOYSA-N titanium oxide Inorganic materials [Ti]=O OGIDPMRJRNCKJF-UHFFFAOYSA-N 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910052692 Dysprosium Inorganic materials 0.000 description 2
- 229910052691 Erbium Inorganic materials 0.000 description 2
- 229910052688 Gadolinium Inorganic materials 0.000 description 2
- 229910052689 Holmium Inorganic materials 0.000 description 2
- CPLXHLVBOLITMK-UHFFFAOYSA-N Magnesium oxide Chemical compound [Mg]=O CPLXHLVBOLITMK-UHFFFAOYSA-N 0.000 description 2
- 229910052771 Terbium Inorganic materials 0.000 description 2
- 229910052775 Thulium Inorganic materials 0.000 description 2
- 229910052769 Ytterbium Inorganic materials 0.000 description 2
- 238000005269 aluminizing Methods 0.000 description 2
- KBQHZAAAGSGFKK-UHFFFAOYSA-N dysprosium atom Chemical compound [Dy] KBQHZAAAGSGFKK-UHFFFAOYSA-N 0.000 description 2
- UYAHIZSMUZPPFV-UHFFFAOYSA-N erbium Chemical compound [Er] UYAHIZSMUZPPFV-UHFFFAOYSA-N 0.000 description 2
- UIWYJDYFSGRHKR-UHFFFAOYSA-N gadolinium atom Chemical compound [Gd] UIWYJDYFSGRHKR-UHFFFAOYSA-N 0.000 description 2
- 238000000227 grinding Methods 0.000 description 2
- KJZYNXUDTRRSPN-UHFFFAOYSA-N holmium atom Chemical compound [Ho] KJZYNXUDTRRSPN-UHFFFAOYSA-N 0.000 description 2
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 2
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 2
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- GZCRRIHWUXGPOV-UHFFFAOYSA-N terbium atom Chemical compound [Tb] GZCRRIHWUXGPOV-UHFFFAOYSA-N 0.000 description 2
- NAWDYIZEMPQZHO-UHFFFAOYSA-N ytterbium Chemical compound [Yb] NAWDYIZEMPQZHO-UHFFFAOYSA-N 0.000 description 2
- QVOIJBIQBYRBCF-UHFFFAOYSA-H yttrium(3+);tricarbonate Chemical compound [Y+3].[Y+3].[O-]C([O-])=O.[O-]C([O-])=O.[O-]C([O-])=O QVOIJBIQBYRBCF-UHFFFAOYSA-H 0.000 description 2
- 229910052765 Lutetium Inorganic materials 0.000 description 1
- 229910018487 Ni—Cr Inorganic materials 0.000 description 1
- NEIHULKJZQTQKJ-UHFFFAOYSA-N [Cu].[Ag] Chemical compound [Cu].[Ag] NEIHULKJZQTQKJ-UHFFFAOYSA-N 0.000 description 1
- 238000013019 agitation Methods 0.000 description 1
- 125000005250 alkyl acrylate group Chemical group 0.000 description 1
- 238000005275 alloying Methods 0.000 description 1
- 238000000498 ball milling Methods 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000005422 blasting Methods 0.000 description 1
- 239000007767 bonding agent Substances 0.000 description 1
- 125000004432 carbon atom Chemical group C* 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 238000005255 carburizing Methods 0.000 description 1
- 239000000969 carrier Substances 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- VNNRSPGTAMTISX-UHFFFAOYSA-N chromium nickel Chemical compound [Cr].[Ni] VNNRSPGTAMTISX-UHFFFAOYSA-N 0.000 description 1
- 238000001816 cooling Methods 0.000 description 1
- 229920001577 copolymer Polymers 0.000 description 1
- QRJOYPHTNNOAOJ-UHFFFAOYSA-N copper gold Chemical compound [Cu].[Au] QRJOYPHTNNOAOJ-UHFFFAOYSA-N 0.000 description 1
- TVZPLCNGKSPOJA-UHFFFAOYSA-N copper zinc Chemical compound [Cu].[Zn] TVZPLCNGKSPOJA-UHFFFAOYSA-N 0.000 description 1
- 238000000354 decomposition reaction Methods 0.000 description 1
- 238000007598 dipping method Methods 0.000 description 1
- 229910003440 dysprosium oxide Inorganic materials 0.000 description 1
- NLQFUUYNQFMIJW-UHFFFAOYSA-N dysprosium(iii) oxide Chemical compound O=[Dy]O[Dy]=O NLQFUUYNQFMIJW-UHFFFAOYSA-N 0.000 description 1
- 229910001938 gadolinium oxide Inorganic materials 0.000 description 1
- 229940075613 gadolinium oxide Drugs 0.000 description 1
- CMIHHWBVHJVIGI-UHFFFAOYSA-N gadolinium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[Gd+3].[Gd+3] CMIHHWBVHJVIGI-UHFFFAOYSA-N 0.000 description 1
- 229910052737 gold Inorganic materials 0.000 description 1
- 239000010931 gold Substances 0.000 description 1
- 229920001519 homopolymer Polymers 0.000 description 1
- 229910052747 lanthanoid Inorganic materials 0.000 description 1
- 150000002602 lanthanoids Chemical class 0.000 description 1
- OHSVLFRHMCKCQY-UHFFFAOYSA-N lutetium atom Chemical compound [Lu] OHSVLFRHMCKCQY-UHFFFAOYSA-N 0.000 description 1
- 238000010907 mechanical stirring Methods 0.000 description 1
- 150000002734 metacrylic acid derivatives Chemical class 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005121 nitriding Methods 0.000 description 1
- 150000003891 oxalate salts Chemical class 0.000 description 1
- IBSDADOZMZEYKD-UHFFFAOYSA-H oxalate;yttrium(3+) Chemical compound [Y+3].[Y+3].[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O.[O-]C(=O)C([O-])=O IBSDADOZMZEYKD-UHFFFAOYSA-H 0.000 description 1
- TWNQGVIAIRXVLR-UHFFFAOYSA-N oxo(oxoalumanyloxy)alumane Chemical compound O=[Al]O[Al]=O TWNQGVIAIRXVLR-UHFFFAOYSA-N 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 229910052763 palladium Inorganic materials 0.000 description 1
- KDLHZDBZIXYQEI-UHFFFAOYSA-N palladium Substances [Pd] KDLHZDBZIXYQEI-UHFFFAOYSA-N 0.000 description 1
- 239000000049 pigment Substances 0.000 description 1
- 229920002401 polyacrylamide Polymers 0.000 description 1
- 229910003451 terbium oxide Inorganic materials 0.000 description 1
- SCRZPWWVSXWCMC-UHFFFAOYSA-N terbium(iii) oxide Chemical compound [O-2].[O-2].[O-2].[Tb+3].[Tb+3] SCRZPWWVSXWCMC-UHFFFAOYSA-N 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B05—SPRAYING OR ATOMISING IN GENERAL; APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D—PROCESSES FOR APPLYING FLUENT MATERIALS TO SURFACES, IN GENERAL
- B05D1/00—Processes for applying liquids or other fluent materials
- B05D1/32—Processes for applying liquids or other fluent materials using means for protecting parts of a surface not to be coated, e.g. using stencils, resists
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/224—Anti-weld compositions; Braze stop-off compositions
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23C—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; SURFACE TREATMENT OF METALLIC MATERIAL BY DIFFUSION INTO THE SURFACE, BY CHEMICAL CONVERSION OR SUBSTITUTION; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL
- C23C10/00—Solid state diffusion of only metal elements or silicon into metallic material surfaces
- C23C10/04—Diffusion into selected surface areas, e.g. using masks
Definitions
- ABSTRACT A solid material containing a rare earth compound suspended in a fugitive carrier is useful in preventing braze and diffusion flow by applying the slurried compound to the material to be brazed or diffusion coated in a continuous layer by conventional methods.
- Alternative compositions are suspensions of rare earth compounds in a fugitive carrier and refractory metal oxides, admixed with rare earth compounds and mixtures thereof suspended in a fugitive carrier.
- This invention relates to a composition and method for preventing braze and diffusion coating flow. More specifically it relates to a suspension of a rare earth or mixed rare earth compound suspended alone in a fugitive carrier or admixed with refractory metal oxides suspended in a fugitive carrier and applied by conventional methods to the material to be brazed or diffusion coated.
- the refractory oxides are used in diffusion coating applications.
- the refractory oxides are used to control the size of the area to be coated and have had only limited success in diffusion coating process such as carburizing, nitriding, and aluminizing.
- the existent stopoffs do not protect the surfaces and the coatings are able to penetrate the stopoff.
- many of the stopoffs themselves have a residual coating which must be removed by fine grinding to produce a marketable finished piece. Overcoming both problems necessitate additional steps and expense.
- a rare earth compound selected from the group consisting of oxides, salts of lower aliphatic and salts of mineral acids and from about 0 to about 60 weight percent of a refractory metal oxide.
- an improved process for brazing comprising: The parts to be brazed are assembled with a filler alloy between the joint; and the joint and a portion of the parts adjacent to the joint are coated, before being brazed, with a substantially uninterrupted layer of a rare earth compound slurry composition as describedabove.
- an improved process for diffusion coating wherein a continuous substantially uninterrupted layer of the composition is applied to a portion of the parts that are not to be diffusion coated.
- FIG. 1 is a side elevational view of one embodiment of the present invention.
- FIG. 2 is a view of the embodiment of FIG. 1 as taken along the lines 22.
- the first part 10 and second part 12 have a filler alloy 13 disposed between the two parts to form a joint.
- a layer 14 of brazing stop-off composition is applied over the joint and a portion of each of part 10 and part 12 adjacent to the joint.
- the layer of brazing stop-off composition l4 prevents the flow of filler alloy. After the brazing the stop-off composition can be rinsed off of the brazed parts.
- the present invention relates to a rare earth compound slurry composition and a method for preventing braze and diffusion coating fllow. Surprisingly, it has been found that when the aforementioned composition is prepared and applied to parts to be brazed and/or diffusion coated the flow of the filler alloy and/or coatings is controlled, and that the stop-off is easily and readily removed after the brazing and/or coating without any appreciable amount of residue.
- yttrium for purposes of this invention, is to be considered one of the rare earth elements and included in the lanthanide series.
- the useful rare earth compounds are the rare earth oxides and heat decomposable rare earth compounds that decompose to form rare earth oxide.
- Useful heat decomposable compounds include the rare earth salts of lower aliphatic acids and mineral acids. As used herein lower aliphatic acids include those having from 1 to about 5 carbon atoms.
- Preferred compounds are the rare earth oxides, oxalates, carbonates, and mixtures thereof.
- Preferred rare earths are yttrium and the heavy rare earths, that is, those having atomic numbers of 64 through 71, namely, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, llutetium and mixtures thereof.
- yttrium oxide and yttrium carbonate are especially preferred.
- Yttrium and any of the heavy rare earths can be the sole component in the solid material that is suspendedin the fugitive carrier, however, mixtures of these compounds can be used if desired.
- yttrium oxide is one of the especially preferred rare earth compounds and beneficial results have been achieved when yttrium oxide is used in the solid material from about 60 to about 70% by weight along with from about 30 to about 40% of a heavy rare earth oxide.
- the solid material can include refractory metal oxides in conjunction with the rare earth compounds.
- the solid material can contain from about 40% to 100% by weight of the rare earth compound and from about to about 60% by weight of a refractory metal oxide such as alumina (A1 0 titania (TiO magnesia (MgO) and the like.
- Solid materials comprising from about 40% to about 90% by weight of a rare earth compound and from about 10% to about 60% by weight of a refractory metal oxide are preferred for some applications.
- a solid material comprising from about 80 to about 90% by weight of yttrium oxide, from about 5 to about of titanium oxide and from about 5 to about 10% of aluminum oxide.
- the solid material can be suspended in a fugitive carrier by any of the methods generally used for suspending pigments in paints. In practice, ball milling of the solids into the fugitive carrier and physical agitation to suspend the solids into the fugitive carrier are usually used.
- a fugitive or volatile carrier is one that will either volatize or decompose to form volatile decomposition products when heated in air to a temperature of about 150 C.
- fugitive carriers that can be employed are polyacrylamides, polyvinylacetates, polyvinyl pyrrolidone, homopolymers and copolymers of the lower alkyl acrylates and methacrylates (e.g. C through C Especially preferred are polyvinyl acetates such as Lacquer L-18 as supplied by Raffi and Swanson, Inc.
- the concentration of the rare earth compound in the carrier is varied as desired, depending on such factors such as the particular method of applying the coating, such as, for example, brushing, spraying, dipping and extruding the desired thickness of the individual coating, the number of coatings to be applied, the viscosity of the carrier, the desired covering power of the stopoff, the desired viscosity of the slurry, and other influencing factors.
- the solid material is present in the composition in an amount corresponding to about 175 to about 1,500 grams per 100 gms of the carrier.
- composition is applied to the desired areas of the parts to be brazed or diffusion coated by the methods well known to one skilled in the art for example, brushing, spraying, extruding, etc.
- brazing the aforementioned composition is generally applied to the joint and a portion of the parts next to the joint so as to prevent the tiller alloy from running and covering the entire work piece when the work piece is brazed.
- diffusion coating the composition is generally applied to the areas of the work piece not to be coated and which will be subjected to an atmosphere of the coating material.
- the powder-like residue can be readily removed such as for example by wiping the residue off with a damp cloth, washing the work piece with water, and air blasting the work piece.
- EXAMPLE 1 About 500 parts of yttrium oxide is ball milled for about 24 hours using alumina balls. The oxide is dried for about 12 hours at about 130 C and hammermilled. About 300 parts of the dried oxide is suspended in 200 parts of a 10 wt. percent solution of polyvinyl pyrrolidone in water by means of mechanical stirring for 24 hours. The resultant suspension (braze stopoff) is applied by brush to a joint and adjacent area of a metal to be brazed and which has a silver-copper-palladium filler alloy, so that the joint and adjacent area are coated. The metal is heated to above about 1742 C. After coating the braze stopoff is washed off the metal piece with water. The filler alloy is contained within the joint with no overflow.
- EXAMPLE 2 About 200 parts of yttrium oxide is added to about 250 parts of lacquer L-18, a low residue polyvinylacetate supplied by Raffi and Swanson, Inc. is ball milled for about 24 hours using alumina balls. The resultant suspension (diffusion coating stopoff) is applied by brush to parts of a turbine blade prior to aluminzing the blade. After coating the diffusion coating stopoff is wiped off with a damp cloth and the parts of the blade coated with the stopoff are not aluminized.
- EXAMPLE 3 About 45 parts yttrium oxide, about 2.5 parts alumina and about 2.5 parts titania are added to about 250 parts of lacquer L-18, a low residue polyvinylacetate supplied by Raffi and Swanson, Inc. is ball milled for about 24 hours using alumina balls. The resultant suspension (diffusion coating stopoff) is poured into the holes of a honeycomb piece of metal prior to diffusion coating it. After cooling the diffusion coating stopoff is wiped off with a cloth and the filled crevices are not coated.
- EXAMPLE 4 About 50 parts are mixed rare earth oxides, containing about yttrium, about 15% ytterbium, about 7% dysprosium, about 6% erbium, about 0.01% gadolinium, about 1.0% holmium, about 0.01% lanthanium,
- lutetium, about 0.1% terbium, and about 0.1% thulium are added to about 250 parts lacquer L-18, a low residue polyvinylacetate supplied by Raffi and Swanson, Inc. is ball milled for about 12 hours using alumina balls.
- the resultant suspension (diffusion coating stopoff) is applied by brush to parts of a turbine blade prior to aluminizing the blade. After coating the diffusion coating stopoff is wiped off with a cloth and the parts of the blade coated with the stopoff are not aluminized.
- brazing and diffusion coating stopoffs are prepared using yttrium carbonate, yttrium oxalate, yttrium oxide admixed with gadolinium oxide, yttrium oxide admixed with terbium oxide and dysprosium oxide and yttrium oxide admixed with alumina in substantially equivalent amounts to yield a composition having substantially the same solids content.
- brazing wherein a first pan and a second part to be brazed are assembled with a filler alloy between said parts to form a joint and are then heated above the liquidus of the filler alloy, the improvement comprising applying a substantially uninterrupted layer of a brazing stopoff composition to said joint and to a portion of said parts adjacent to said joint, before being brazed, said composition consisting essentially of a suspension of a solid material in a fugisaid braze stopoff composition is applied by brushing.
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- Engineering & Computer Science (AREA)
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Abstract
A solid material containing a rare earth compound suspended in a fugitive carrier is useful in preventing braze and diffusion flow by applying the slurried compound to the material to be brazed or diffusion coated in a continuous layer by conventional methods. Alternative compositions are suspensions of rare earth compounds in a fugitive carrier and refractory metal oxides, admixed with rare earth compounds and mixtures thereof suspended in a fugitive carrier.
Description
United States Patent [191 Behringer et al.
111'] 3,906,617 1451 Sept. 23, 1975 METHOD OF PREVENTING BRAZE AND DIFFUSION FLOW Inventors: Cecil Behringer, Edina, Minn.;
George J. Kamin, Towanda, Pa.
GTE Sylvania Incorporated, Stamford, Conn.
Filed: May 7, 1971 Appl. No.: 141,351
Related US. Application Data Division of Ser. No. 16,583, March 4, 1970, Pat. No. 3,623,921.
Assignee:
US. Cl 228/118; 228/215 Int. Cl B23k 1/04 Field of Search 29/4709 References Cited UNITED STATES PATENTS 8/1958 Sangdahl, Jr. 29/4709 .fimeexmasmx 2,906,006 9/1959 Neel 29/4709 X 3,052,964 9/1962 Heuer 29/470.9 X 3,478,413 11/1969 Gadd 29/490 3,667,109 6/1972 Alceniuso... 2 /4709 X Primary Examiner-Francis S. Husar Assistant Examiner-Carl A. Rowold Attorney, Agent, or- FirmNo rman J. OMalley; Donald R. Castle; William H. McNeill [57] ABSTRACT A solid material containing a rare earth compound suspended in a fugitive carrier is useful in preventing braze and diffusion flow by applying the slurried compound to the material to be brazed or diffusion coated in a continuous layer by conventional methods. Alternative compositions are suspensions of rare earth compounds in a fugitive carrier and refractory metal oxides, admixed with rare earth compounds and mixtures thereof suspended in a fugitive carrier.
2 Claims, 2 Drawing Figures \I US Patent Sept. 23,1975 3,906,617
METHOD OF PREVENTING BRAZE AND DIFFUSION FLOW CROSS REFERENCE TO RELATED APPLICATION This application is a divisional application of Ser. No. 16,583, filed Mar. 4, 1970 and now US. Pat. No. 3,623,921, which is assigned to the assignee of the pres ent invention.
BACKGROUND OF THE INVENTION This invention relates to a composition and method for preventing braze and diffusion coating flow. More specifically it relates to a suspension of a rare earth or mixed rare earth compound suspended alone in a fugitive carrier or admixed with refractory metal oxides suspended in a fugitive carrier and applied by conventional methods to the material to be brazed or diffusion coated.
In brazing applications it is usually necessary to apply a material to the joint and adjacent portion of the work piece to be brazed to prevent the tiller alloy from flowing over the entire work piece. The most commonly used materials in this application are composed of highly refractory oxide such as alumina (A1 titania (TiO and magnesia (MgO). These materials have shown varying degrees of utility with the aluminumsilica, copper-gold, nickel-chromium, and copper-zinc filler alloys used in brazing. However, in brazing with the newer filler alloys such as palladium-nickel-gold and silver-copper palladium, the existent stopoffs do not protect the surfaces and varying degrees of creep, break through, and undesired adhesion occur. Also, in the newer applications the inefficiency of the presently available stopoffs necessitate grinding of the joined surfaces to remove the undesired bonding agent and to produce a clear sharp junction. Overcoming these problems necessitate additional steps and expense.
Generally the same highly refractory oxides are used in diffusion coating applications. In this case, the refractory oxides are used to control the size of the area to be coated and have had only limited success in diffusion coating process such as carburizing, nitriding, and aluminizing. For example, in the diffusion coating of turbine parts such as nozzles, blades, and the like, the existent stopoffs do not protect the surfaces and the coatings are able to penetrate the stopoff. Also, many of the stopoffs themselves have a residual coating which must be removed by fine grinding to produce a marketable finished piece. Overcoming both problems necessitate additional steps and expense.
It is believed, therefore, that a brazing and diffusion coating stopoff which prevents brazing and diffusion coating flow that is easily and readily removed without having an appreciable amount of residue or necessitating costly additional steps is an advancement in the art.
SUMMARY OF THE INVENTION weight percent of a rare earth compound selected from the group consisting of oxides, salts of lower aliphatic and salts of mineral acids and from about 0 to about 60 weight percent of a refractory metal oxide.
In accordance with another aspect of this invention, there is provided an improved process for brazing. The parts to be brazed are assembled with a filler alloy between the joint; and the joint and a portion of the parts adjacent to the joint are coated, before being brazed, with a substantially uninterrupted layer of a rare earth compound slurry composition as describedabove.
In accordance with still another aspect of this invention, there is provided an improved process for diffusion coating wherein a continuous substantially uninterrupted layer of the composition is applied to a portion of the parts that are not to be diffusion coated.
BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a side elevational view of one embodiment of the present invention.
FIG. 2 is a view of the embodiment of FIG. 1 as taken along the lines 22.
Referring to FIG. 1 and FIG. 2 in more particularity, the first part 10 and second part 12 have a filler alloy 13 disposed between the two parts to form a joint. A layer 14 of brazing stop-off composition is applied over the joint and a portion of each of part 10 and part 12 adjacent to the joint. When the filler alloy 13 is heated above its liquidus, the layer of brazing stop-off composition l4 prevents the flow of filler alloy. After the brazing the stop-off composition can be rinsed off of the brazed parts.
DESCRIPTION OF THE PREFERRED EMBODIMENTS For a better understanding of the present invention together with other and further objects, advantages and capabilities thereof, reference is made to the following disclosure and appended claims in connection with the above description of some of the aspects of the invention.
The present invention relates to a rare earth compound slurry composition and a method for preventing braze and diffusion coating fllow. Surprisingly, it has been found that when the aforementioned composition is prepared and applied to parts to be brazed and/or diffusion coated the flow of the filler alloy and/or coatings is controlled, and that the stop-off is easily and readily removed after the brazing and/or coating without any appreciable amount of residue.
Referring now to the invention with greater particularity, yttrium, for purposes of this invention, is to be considered one of the rare earth elements and included in the lanthanide series. The useful rare earth compounds are the rare earth oxides and heat decomposable rare earth compounds that decompose to form rare earth oxide. Useful heat decomposable compounds include the rare earth salts of lower aliphatic acids and mineral acids. As used herein lower aliphatic acids include those having from 1 to about 5 carbon atoms. Preferred compounds are the rare earth oxides, oxalates, carbonates, and mixtures thereof. Preferred rare earths are yttrium and the heavy rare earths, that is, those having atomic numbers of 64 through 71, namely, gadolinium, terbium, dysprosium, holmium, erbium, thulium, ytterbium, llutetium and mixtures thereof. Of these yttrium oxide and yttrium carbonate are especially preferred. Yttrium and any of the heavy rare earths can be the sole component in the solid material that is suspendedin the fugitive carrier, however, mixtures of these compounds can be used if desired.
For example, yttrium oxide is one of the especially preferred rare earth compounds and beneficial results have been achieved when yttrium oxide is used in the solid material from about 60 to about 70% by weight along with from about 30 to about 40% of a heavy rare earth oxide.
As previously mentioned the solid material can include refractory metal oxides in conjunction with the rare earth compounds. The solid material can contain from about 40% to 100% by weight of the rare earth compound and from about to about 60% by weight of a refractory metal oxide such as alumina (A1 0 titania (TiO magnesia (MgO) and the like. Solid materials comprising from about 40% to about 90% by weight of a rare earth compound and from about 10% to about 60% by weight of a refractory metal oxide are preferred for some applications. Especially preferred is a solid material comprising from about 80 to about 90% by weight of yttrium oxide, from about 5 to about of titanium oxide and from about 5 to about 10% of aluminum oxide.
The solid material can be suspended in a fugitive carrier by any of the methods generally used for suspending pigments in paints. In practice, ball milling of the solids into the fugitive carrier and physical agitation to suspend the solids into the fugitive carrier are usually used. As used herein, a fugitive or volatile carrier is one that will either volatize or decompose to form volatile decomposition products when heated in air to a temperature of about 150 C. Examples of fugitive carriers that can be employed are polyacrylamides, polyvinylacetates, polyvinyl pyrrolidone, homopolymers and copolymers of the lower alkyl acrylates and methacrylates (e.g. C through C Especially preferred are polyvinyl acetates such as Lacquer L-18 as supplied by Raffi and Swanson, Inc.
The concentration of the rare earth compound in the carrier is varied as desired, depending on such factors such as the particular method of applying the coating, such as, for example, brushing, spraying, dipping and extruding the desired thickness of the individual coating, the number of coatings to be applied, the viscosity of the carrier, the desired covering power of the stopoff, the desired viscosity of the slurry, and other influencing factors. Typically, the solid material is present in the composition in an amount corresponding to about 175 to about 1,500 grams per 100 gms of the carrier.
The composition is applied to the desired areas of the parts to be brazed or diffusion coated by the methods well known to one skilled in the art for example, brushing, spraying, extruding, etc. In brazing the aforementioned composition is generally applied to the joint and a portion of the parts next to the joint so as to prevent the tiller alloy from running and covering the entire work piece when the work piece is brazed. Whereas in diffusion coating, the composition is generally applied to the areas of the work piece not to be coated and which will be subjected to an atmosphere of the coating material.
After the work piece is brazed or diffusion coated, the powder-like residue can be readily removed such as for example by wiping the residue off with a damp cloth, washing the work piece with water, and air blasting the work piece.
To more fully illustrate the present invention, the following detailed examples are presented. All parts, proportions, and percentages are by weight, unless otherwise given.
EXAMPLE 1 About 500 parts of yttrium oxide is ball milled for about 24 hours using alumina balls. The oxide is dried for about 12 hours at about 130 C and hammermilled. About 300 parts of the dried oxide is suspended in 200 parts of a 10 wt. percent solution of polyvinyl pyrrolidone in water by means of mechanical stirring for 24 hours. The resultant suspension (braze stopoff) is applied by brush to a joint and adjacent area of a metal to be brazed and which has a silver-copper-palladium filler alloy, so that the joint and adjacent area are coated. The metal is heated to above about 1742 C. After coating the braze stopoff is washed off the metal piece with water. The filler alloy is contained within the joint with no overflow.
EXAMPLE 2 About 200 parts of yttrium oxide is added to about 250 parts of lacquer L-18, a low residue polyvinylacetate supplied by Raffi and Swanson, Inc. is ball milled for about 24 hours using alumina balls. The resultant suspension (diffusion coating stopoff) is applied by brush to parts of a turbine blade prior to aluminzing the blade. After coating the diffusion coating stopoff is wiped off with a damp cloth and the parts of the blade coated with the stopoff are not aluminized.
EXAMPLE 3 About 45 parts yttrium oxide, about 2.5 parts alumina and about 2.5 parts titania are added to about 250 parts of lacquer L-18, a low residue polyvinylacetate supplied by Raffi and Swanson, Inc. is ball milled for about 24 hours using alumina balls. The resultant suspension (diffusion coating stopoff) is poured into the holes of a honeycomb piece of metal prior to diffusion coating it. After cooling the diffusion coating stopoff is wiped off with a cloth and the filled crevices are not coated.
EXAMPLE 4 About 50 parts are mixed rare earth oxides, containing about yttrium, about 15% ytterbium, about 7% dysprosium, about 6% erbium, about 0.01% gadolinium, about 1.0% holmium, about 0.01% lanthanium,
about 1.0% lutetium, about 0.1% terbium, and about 0.1% thulium, are added to about 250 parts lacquer L-18, a low residue polyvinylacetate supplied by Raffi and Swanson, Inc. is ball milled for about 12 hours using alumina balls. The resultant suspension (diffusion coating stopoff) is applied by brush to parts of a turbine blade prior to aluminizing the blade. After coating the diffusion coating stopoff is wiped off with a cloth and the parts of the blade coated with the stopoff are not aluminized.
Substantially the same results are obtained when the brazing and diffusion coating stopoffs are prepared using yttrium carbonate, yttrium oxalate, yttrium oxide admixed with gadolinium oxide, yttrium oxide admixed with terbium oxide and dysprosium oxide and yttrium oxide admixed with alumina in substantially equivalent amounts to yield a composition having substantially the same solids content.
While there has been shown and described what are at present considered the preferred embodiments of the invention, it will be obvious to those skilled in the art that various changes and modifications may be made therein without departing from the scope of the invention as defined by the appended claims.
We claim:
1. In the process of brazing, wherein a first pan and a second part to be brazed are assembled with a filler alloy between said parts to form a joint and are then heated above the liquidus of the filler alloy, the improvement comprising applying a substantially uninterrupted layer of a brazing stopoff composition to said joint and to a portion of said parts adjacent to said joint, before being brazed, said composition consisting essentially of a suspension of a solid material in a fugisaid braze stopoff composition is applied by brushing.
Claims (2)
1. IN THE PROCESS OF BRAZING, WHEREIN A FIRST PART AND A SECOND PART TO BE BRAZED ARE ASSEMBLED WITH A FILLER ALLOY BETWEEN SAID PARTS TO FORM A JOINT AND ARE HEATED ABOVE THE LIQUIDUS OF THE FILLER ALLOY, THE IMPROVEMENT COMPRISING APPLYING A SUBSTANTIALLY UNINTERRUPTED LAYER OF A BRAZING STOPOFF COMPOSITION TO SAID JOINT AND TO A PORTION OF SAID PARTS ADJACENT TO SA ID JOINT, BEFORE BEING BRAZED, SAID COMPOSITION CONSISTING ESSENTIALLY OF A SUSPENSION OF A SOLID MATERIAL IN A FUGITIVE CARRIER IN WEIGHT RATIOS OF ABOUT 15:85 TO ABOUT 60:40 RESPECTIVELY, SAID SOLID MATERIAL COMPRISING FROM ABOUT 40 TO ABOUT 100 WEIGHT PERCENT BASED ON THE TOTAL WEIGHT OF SAID SOLID MATERIAL OF A RARE EARTH COMPOUND SELECTED FROM THE GROUP CONSISTING OF RARE EARTH OXIDES, RARE EARTH SALTS OF LOWER ALIPHATIC ACIDS, RARE EARTH SALTS OF MINERAL ACIDS AND MIXTURES THEREOF AND FROM ABOUT 0 TO ABOUT 60 WEIGHT PERCENT BASED UPON THE TOTAL WEIGHT OF SAID SOLID MATERIAL OF A REFACTORY METAL OXIDE.
2. An improvement according to claim 1 wherein said braze stopoff composition is applieD by brushing.
Priority Applications (2)
Application Number | Priority Date | Filing Date | Title |
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US141351A US3906617A (en) | 1970-03-04 | 1971-05-07 | Method of preventing braze and diffusion flow |
US00309367A US3837880A (en) | 1971-05-07 | 1972-11-24 | Method of preventing coating diffusion flow |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US1658370A | 1970-03-04 | 1970-03-04 | |
US141351A US3906617A (en) | 1970-03-04 | 1971-05-07 | Method of preventing braze and diffusion flow |
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US3906617A true US3906617A (en) | 1975-09-23 |
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US141351A Expired - Lifetime US3906617A (en) | 1970-03-04 | 1971-05-07 | Method of preventing braze and diffusion flow |
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US4220276A (en) * | 1978-08-25 | 1980-09-02 | Rockwell International Corporation | Method for fabricating superplastically formed/diffusion bonded structures |
US4293089A (en) * | 1979-05-08 | 1981-10-06 | The United States Of America As Represented By The United States Department Of Energy | Brazing method |
US4303570A (en) * | 1978-08-25 | 1981-12-01 | Rockwell International Corporation | Composition for fabricating superplastically formed/diffusion bonded structures |
US4439250A (en) * | 1983-06-09 | 1984-03-27 | International Business Machines Corporation | Solder/braze-stop composition |
US4722125A (en) * | 1984-05-25 | 1988-02-02 | Peng Da H | Method for producing a tungsten carbide tip punch |
EP0346266A1 (en) * | 1988-06-10 | 1989-12-13 | United Technologies Corporation | Method for applying diffusion coating masks |
US4929284A (en) * | 1988-12-16 | 1990-05-29 | General Electric Company | Water removable solder stop |
US5024368A (en) * | 1989-08-01 | 1991-06-18 | British Aerospace | Stopping-off method for use with diffusion bonding |
US5511721A (en) * | 1994-11-07 | 1996-04-30 | General Electric Company | Braze blocking insert for liquid phase brazing operations |
US5830585A (en) * | 1994-06-09 | 1998-11-03 | Honda Giken Kogyo Kabushiki Kaisha | Article made by joining two members together, and a brazing filler metal |
US6240640B1 (en) * | 1998-11-19 | 2001-06-05 | Showa Aircraft Industry Co., Ltd. | Method for manufacturing honeycomb structures made of titanium |
US6460754B1 (en) * | 2000-08-02 | 2002-10-08 | Gen Electric | Prevention of braze alloy flow and stopoff material therefor |
EP2078578A1 (en) * | 2008-01-10 | 2009-07-15 | Siemens Aktiengesellschaft | Soldering of holes, method for coating and soldered rods |
US20160097691A1 (en) * | 2013-05-17 | 2016-04-07 | Endress+Hauser Gmbh+Co. Kg | Ceramic pressure measurement cell and method for production thereof |
CN107855684A (en) * | 2017-12-01 | 2018-03-30 | 温州宏丰电工合金股份有限公司 | A kind of preparation method for the stop-off gent for being used for gas brazing or fused salt dip brazing |
CN107877036A (en) * | 2017-12-02 | 2018-04-06 | 温州宏丰电工合金股份有限公司 | A kind of stop-off gent that small pore passage structure is protected in vacuum brazing |
CN107984117A (en) * | 2017-12-01 | 2018-05-04 | 温州宏丰电工合金股份有限公司 | A kind of stop-off gent for being used for gas brazing or fused salt dip brazing |
CN108044259A (en) * | 2017-12-01 | 2018-05-18 | 温州宏丰电工合金股份有限公司 | A kind of preparation method of stop-off gent for stainless-steel vacuum soldering |
CN108098093A (en) * | 2017-12-01 | 2018-06-01 | 温州宏丰电工合金股份有限公司 | A kind of stop-off gent for stainless-steel vacuum soldering |
US10307851B2 (en) | 2016-12-14 | 2019-06-04 | Raytheon Company | Techniques for providing stop-offs for brazing materials or other materials on structures being joined |
US11338396B2 (en) * | 2018-03-08 | 2022-05-24 | Rolls-Royce Corporation | Techniques and assemblies for joining components |
US11731218B2 (en) | 2015-02-26 | 2023-08-22 | Rolls-Royce Corporation | Repair of dual walled metallic components using braze material |
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Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US4220276A (en) * | 1978-08-25 | 1980-09-02 | Rockwell International Corporation | Method for fabricating superplastically formed/diffusion bonded structures |
US4303570A (en) * | 1978-08-25 | 1981-12-01 | Rockwell International Corporation | Composition for fabricating superplastically formed/diffusion bonded structures |
US4293089A (en) * | 1979-05-08 | 1981-10-06 | The United States Of America As Represented By The United States Department Of Energy | Brazing method |
US4439250A (en) * | 1983-06-09 | 1984-03-27 | International Business Machines Corporation | Solder/braze-stop composition |
US4722125A (en) * | 1984-05-25 | 1988-02-02 | Peng Da H | Method for producing a tungsten carbide tip punch |
EP0346266A1 (en) * | 1988-06-10 | 1989-12-13 | United Technologies Corporation | Method for applying diffusion coating masks |
US4929284A (en) * | 1988-12-16 | 1990-05-29 | General Electric Company | Water removable solder stop |
US5024368A (en) * | 1989-08-01 | 1991-06-18 | British Aerospace | Stopping-off method for use with diffusion bonding |
US5830585A (en) * | 1994-06-09 | 1998-11-03 | Honda Giken Kogyo Kabushiki Kaisha | Article made by joining two members together, and a brazing filler metal |
US6214480B1 (en) | 1994-06-09 | 2001-04-10 | Honda Giken Kogyo Kabushiki Kaisha | Article made by joining two members together, and a brazing filler metal |
US5511721A (en) * | 1994-11-07 | 1996-04-30 | General Electric Company | Braze blocking insert for liquid phase brazing operations |
US5935718A (en) * | 1994-11-07 | 1999-08-10 | General Electric Company | Braze blocking insert for liquid phase brazing operation |
US6240640B1 (en) * | 1998-11-19 | 2001-06-05 | Showa Aircraft Industry Co., Ltd. | Method for manufacturing honeycomb structures made of titanium |
US6460754B1 (en) * | 2000-08-02 | 2002-10-08 | Gen Electric | Prevention of braze alloy flow and stopoff material therefor |
EP2078578A1 (en) * | 2008-01-10 | 2009-07-15 | Siemens Aktiengesellschaft | Soldering of holes, method for coating and soldered rods |
US20100288823A1 (en) * | 2008-01-10 | 2010-11-18 | Francis-Jurjen Ladru | Application of Solder to Holes, Coating Processes and Small Solder Rods |
US20160097691A1 (en) * | 2013-05-17 | 2016-04-07 | Endress+Hauser Gmbh+Co. Kg | Ceramic pressure measurement cell and method for production thereof |
US10330549B2 (en) * | 2013-05-17 | 2019-06-25 | Endress+Hauser Se+Co.Kg | Ceramic pressure measurement cell and method for production thereof |
US11731218B2 (en) | 2015-02-26 | 2023-08-22 | Rolls-Royce Corporation | Repair of dual walled metallic components using braze material |
US10307851B2 (en) | 2016-12-14 | 2019-06-04 | Raytheon Company | Techniques for providing stop-offs for brazing materials or other materials on structures being joined |
CN108098093B (en) * | 2017-12-01 | 2020-04-03 | 温州宏丰电工合金股份有限公司 | Flow resisting agent for stainless steel vacuum brazing |
CN108098093A (en) * | 2017-12-01 | 2018-06-01 | 温州宏丰电工合金股份有限公司 | A kind of stop-off gent for stainless-steel vacuum soldering |
CN108044259A (en) * | 2017-12-01 | 2018-05-18 | 温州宏丰电工合金股份有限公司 | A kind of preparation method of stop-off gent for stainless-steel vacuum soldering |
CN107984117A (en) * | 2017-12-01 | 2018-05-04 | 温州宏丰电工合金股份有限公司 | A kind of stop-off gent for being used for gas brazing or fused salt dip brazing |
CN108044259B (en) * | 2017-12-01 | 2020-04-03 | 温州宏丰电工合金股份有限公司 | Preparation method of flow resisting agent for stainless steel vacuum brazing |
CN107855684A (en) * | 2017-12-01 | 2018-03-30 | 温州宏丰电工合金股份有限公司 | A kind of preparation method for the stop-off gent for being used for gas brazing or fused salt dip brazing |
CN107877036A (en) * | 2017-12-02 | 2018-04-06 | 温州宏丰电工合金股份有限公司 | A kind of stop-off gent that small pore passage structure is protected in vacuum brazing |
CN107877036B (en) * | 2017-12-02 | 2020-04-03 | 温州宏丰电工合金股份有限公司 | Flow resisting agent for protecting micro-pore structure in vacuum brazing |
US11338396B2 (en) * | 2018-03-08 | 2022-05-24 | Rolls-Royce Corporation | Techniques and assemblies for joining components |
US12036627B2 (en) | 2018-03-08 | 2024-07-16 | Rolls-Royce Corporation | Techniques and assemblies for joining components |
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