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WO1992007110A1 - Bain de decapage et procede servant a decaper des composes de titane sur des metaux de base - Google Patents

Bain de decapage et procede servant a decaper des composes de titane sur des metaux de base Download PDF

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Publication number
WO1992007110A1
WO1992007110A1 PCT/US1991/007505 US9107505W WO9207110A1 WO 1992007110 A1 WO1992007110 A1 WO 1992007110A1 US 9107505 W US9107505 W US 9107505W WO 9207110 A1 WO9207110 A1 WO 9207110A1
Authority
WO
WIPO (PCT)
Prior art keywords
mole
stripping
acid
solution
hydrogen peroxide
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.)
Ceased
Application number
PCT/US1991/007505
Other languages
English (en)
Inventor
Jiinjen Albert Sue
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.)
Praxair ST Technology Inc
Praxair Surface Technologies Inc
Original Assignee
Union Carbide Coatings Service Technology Corp
Union Carbide Coatings Service 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 Union Carbide Coatings Service Technology Corp, Union Carbide Coatings Service Corp filed Critical Union Carbide Coatings Service Technology Corp
Priority to EP91919089A priority Critical patent/EP0506928B1/fr
Priority to DE69113020T priority patent/DE69113020T2/de
Publication of WO1992007110A1 publication Critical patent/WO1992007110A1/fr
Anticipated expiration legal-status Critical
Ceased legal-status Critical Current

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Classifications

    • 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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
    • C23G1/19—Iron or steel
    • 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
    • C23G—CLEANING OR DE-GREASING OF METALLIC MATERIAL BY CHEMICAL METHODS OTHER THAN ELECTROLYSIS
    • C23G1/00—Cleaning or pickling metallic material with solutions or molten salts
    • C23G1/14—Cleaning or pickling metallic material with solutions or molten salts with alkaline solutions
    • C23G1/20—Other heavy metals

Definitions

  • High performance components in aircraft engine turbomachines such as compressor blades, bearings and gears are typically coated with a titanium metal compound such as TiN to improve their wear characteristics and to provide erosion
  • the engine parts are cast or otherwise molded or machined from superalloys, stainless steels or alloy steels and represent very expensive precision components. Removal of the coating from the underlying base metal is necessary if a defect is discovered in the coating and/or for restoring worn components. It is essential to strip the protective coating from the base metal without suffering any detrimental attack to the underlying base metal.
  • stripping solutions containing hydrogen peroxide are known there is no known aqueous based stripping solution using hydrogen peroxide which will permit the removal of a coating of a titanium compound from a solid base metal composed of a superalloy, stainless steel or alloy steel without causing detrimental attack to the underlying base metal.
  • a chemical stripping solution comprising hydrogen peroxide is described in U.S. Patent Nos. 4,554,049, 4,410,396 and
  • the process of the present invention for stripping a coating of a titanium compound from an underlying base metal without suffering chemical attack to the base metal comprises the steps of:
  • the stripping composition of the present invention comprises an aqueous solution including an alkali source of hydroxyl ions, a source of hydrogen peroxide and an acid with the constituents of the solution in a concentration such that the pH of the solution is above 8.
  • Figure 1 is a plot of stripping efficiency versus the content of the preferred acid in mole per liter for removing a TiN coating from an Inconel 718 base metal;
  • Figure 2 is a plot similar to that of Figure 1 showing stripping efficiency as a function of the content of NH 4 OH in mole per liter in the stripping solution of the present invention
  • Figure 3 is another plot similar to that of Figure 1 of stripping efficiency as a function of the content of hydrogen peroxide in mole per liter in the stripping solution of the present invention
  • Figure 4 is a plot of the solution stripping rate for stripping TiN from an Inconel 718 coupon as a function of the solution operating temperature
  • Figure 5 is a plot of the solution active life of a preferred solution composition for removing TiN from Inconel 718 base metal substrates and the stripping efficiency as a function of temperature.
  • any coating composition of a titanium compound can be removed from any base metal substrate by the process of the present invention without detrimentally attacking the base metal.
  • the invention is particularly suited to the removal of TiN or TiB 2 from a base metal composed of stainless steels, superalloys or alloy steels.
  • the stripping solution of the present invention comprises the following three components: a source of hydrogen peroxide, an alkaline source of hydroxyl ions and a suitable acid in various
  • stripping solution is prepared by first combining the source of hydrogen peroxide with water.
  • the source of hydrogen peroxide should be present in a minimum concentration of .29 mole per liter and in a
  • concentration range of between .29 to about 4.71 mole per liter (mole/L).
  • Any source of hydrogen peroxide such as a perborate, as is well known to those skilled in the art, may be used.
  • Other sources of hydrogen peroxide such as a perborate, as is well known to those skilled in the art, may be used.
  • the alkali source of hydroxyl ions is then added to the solution.
  • the hydroxyl ion is preferably added in combination with ammonium ions through the addition of ammonium hydroxide (NH 4 OH).
  • the source of hydroxyl ions should be present in the stripping solution in a concentration of at least 0.29 mole/L and preferably between .29 mole/L and 3.23 mole/L.
  • An acid must also be present in the solution at a concentration of 0.026 mole/L and preferably between 0.026 mole/L and 0.76 mole/L.
  • Any acid which will not corrode the base metal may be used, preferably an organic carboxyl or carboxyl-hydroxyl group acid such as lactic acid, oxalic acid, tartaric acid, formic acid, propionic acid or citric acid.
  • a diluted inorganic acid such as, for example, acetic acid, nitric acid, hydrochloric acid and sulfuric acid may also be used provided it will not chemically attack the base metal and is low enough in
  • the pH of the stripping solution is critical to the present invention and must be above pH 8 to be effective.
  • the preferred pH range is between pH 9-14 with a pH range of 10-12 being optimum.
  • the pH of the solution may be controlled by adjusting the concentration of alkali, peroxide and organic acid relative to one another provided each is held to a concentration within the preferred range.
  • alkali ions such as sodium or potassium ions may be added to the stripping solution by the addition of NaOH and/or KOH to establish the desired mole concentration and/or to adjust the pH of the solution.
  • a minimum stripping efficiency of 1 x 10 -2 g/cm 2 /L and preferably above 2 x 10 -2 g/cm 2 /L is necessary for the stripping solution to be acceptable for commercial practice.
  • the stripping efficiency is determined based on total weight loss of the coating per unit coating surface area for a given volume of stripping solution over a time period until the solution is considered inactive.
  • Inconel 718 is a registered trademark of the
  • Citric acid is the preferred acid component although any of the other acids, as heretofore described, may be substituted for citric acid at equivalent concentration or equivalent pH levels to produce substantially
  • the concentration of citric acid should be above at least about 0.026 mole/L and preferably above 0.052 mole/L.
  • the maximum concentration of citric acid is approximately 0.76 mole/L.
  • Table II should be read in conjunction with Figure 2 which is based on the data of Table II and shows the effect of varying the concentration of ammonium hydroxide (NH 4 OH) in the stripping
  • the minimum concentration of hydrogen peroxide is about 0.29 mole/L and preferably above 0.59 mole/L.
  • the temperature of the solution has an influence on the stripping rate
  • the stripping rate is expressed in terms of the total weight loss (in grams) of the coating per unit area (in cm 2 ) per unit volume (in liters) per unit time (in minutes). As shown in Figure 4 the optimum stripping rate is realized at a solution temperature exceeding 50°C and preferably between 60°C and 85oC.
  • Figure 5 is a plot of the solution active life in minutes as well as stripping efficiency against temperature.
  • a preferred solution of H 2 O + 1.32 mole/L H 2 O 2 + 1.09 mole/L NH 4 OH + 0.16 mole/L citric acid was used to develop the plot.
  • the solution active life was found to decrease exponentially with increasing temperature from about 1000 minutes at 25°C to about 24 minutes at about 95°C.
  • the stripping efficiency also is a preferred solution of H 2 O + 1.32 mole/L H 2 O 2 + 1.09 mole/L NH 4 OH + 0.16 mole/L citric acid.
  • Table IV is a compilation of the data obtained using various alkali ammonium compounds and NaOH at different pH levels for
  • NH 4 OH is the preferred alkali source.
  • the effective concentration for the three critical components, viz., a source of hydrogen peroxide, an alkali source of hydroxyl ions and acid is 0.29 mole/L to 4.71 mole/L, 0.29 mole/L to 3.23 mole/L and 0.026 mole/L to 0.76 mole/L, respectively.
  • H 2 O 2 ; NH 4 OH and citric acid the preferred concentration is 0.59 mole/L to 4.71 mole/L, 0.37 mole/L to 3.23 mole and 0.05 mole/L to 0.66 mole/L, respectively.
  • the base metal in the test coupons were all of Inconel 718 other coupons including TiN coated stainless steels such as AISI44OC and AISI 17-4 PH and alloy steels such as M50, M50NIL and Pyrowear 53 were tested using the preferred stripping solution. All demonstrated similar behavior to the TiN coated Inconel 718 coupons with no deleterious effect on the base metal.
  • the hydrogen peroxide component in the stripping solution of the present invention may be generated in situ from any source of peroxide which dissociates in water to form hydrogen peroxide such as a perborate, e.g. sodium perborate tetrahydrate (NaBO 3 ⁇ 4H 2 O) or any other know peroxide compound which will readily dissociate into hydrogen peroxide in the presence of water at atmospheric pressure and within the operating temperatures of the present invention.
  • a perborate e.g. sodium perborate tetrahydrate (NaBO 3 ⁇ 4H 2 O) or any other know peroxide compound which will readily dissociate into hydrogen peroxide in the presence of water at atmospheric pressure and within the operating temperatures of the present invention.
  • Ammonium peroxydisulfate ((NH 4 ) 2 S 2 O 8 ) is not a suitable source of hydrogen peroxide for the present invention as is evident from the following Table V despite the fact that ammonium
  • peroxydisulfate is used to commercially produce hydrogen peroxide by hydrolysis at reduced pressure and elevated temperature.
  • TiN coated Inconel 718 coupons (1.5x25x50 mm) were immersed into separate peroxide containing solutions with a specified pH of above 8 and at temperatures of between 60°C and 65°C to evaluate the stripping effectiveness of the solutions with the different sources of peroxide.
  • Tables V and VI show the results of corrosion on the base metal when the acid component in the stripping solution contains the Cl- ion.
  • solution No. 34 and 36 NH 4 Cl and CH 3 OH were used instead of an organic acid and in solutions No. 37-40 HCl was used.
  • Both TiN coated Inconel 718 and 410 stainless steel coupons (1.5x25x50 mm in size) were immersed into the solution No. 36 and only 410 stainless steel exhibited corrosion attack due to the presence of the Cl- ion from the NH 4 Cl solution.
  • HCl was used as the acid component to strip TiN from different substrate materials at different concentration levels. Accordingly, the chloride concentration levels that cause pitting vary with the substrate material composition. If an acid containing the chloride ion is used in the stripping solution, the concentration of acid should be determined according to the substrate material used.

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  • Chemical & Material Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • General Chemical & Material Sciences (AREA)
  • Engineering & Computer Science (AREA)
  • Materials Engineering (AREA)
  • Mechanical Engineering (AREA)
  • Metallurgy (AREA)
  • Organic Chemistry (AREA)
  • ing And Chemical Polishing (AREA)
  • Detergent Compositions (AREA)
  • Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

Abstract

Bain à décaper aqueux et procédé servant à éliminer sélectivement un composé de titane sur un métal de base. La solution aqueuse contient une source de peroxyde d'hydrogène, une source alcaline d'ions hydroxyle et un acide, la concentration des constituants étant telle que le pH de la solution est supérieur à 8.
PCT/US1991/007505 1990-10-19 1991-10-18 Bain de decapage et procede servant a decaper des composes de titane sur des metaux de base Ceased WO1992007110A1 (fr)

Priority Applications (2)

Application Number Priority Date Filing Date Title
EP91919089A EP0506928B1 (fr) 1990-10-19 1991-10-18 Bain de decapage et procede servant a decaper des composes de titane sur des metaux de base
DE69113020T DE69113020T2 (de) 1990-10-19 1991-10-18 Beizzusammensetzung und verfahren zur beizung von titanverbindungen aus metallsubstraten.

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US59983390A 1990-10-19 1990-10-19
US599,833 1990-10-19
US74309391A 1991-08-09 1991-08-09
US743,093 1991-08-09

Publications (1)

Publication Number Publication Date
WO1992007110A1 true WO1992007110A1 (fr) 1992-04-30

Family

ID=27083467

Family Applications (1)

Application Number Title Priority Date Filing Date
PCT/US1991/007505 Ceased WO1992007110A1 (fr) 1990-10-19 1991-10-18 Bain de decapage et procede servant a decaper des composes de titane sur des metaux de base

Country Status (5)

Country Link
EP (1) EP0506928B1 (fr)
JP (1) JP2989265B2 (fr)
CA (1) CA2071944C (fr)
DE (1) DE69113020T2 (fr)
WO (1) WO1992007110A1 (fr)

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024642A1 (fr) * 1997-11-10 1999-05-20 Balzers Hochvakuum Ag Procede pour l'enlevement de couches sur des corps
WO1999064646A1 (fr) * 1998-06-11 1999-12-16 Unaxis Trading Ag Procede pour enlever des couches de substance dure
RU2156322C2 (ru) * 1998-07-21 2000-09-20 Акционерное общество открытого типа "Уральский завод гражданской авиации" Состав для очистки металлических поверхностей
US7611588B2 (en) 2004-11-30 2009-11-03 Ecolab Inc. Methods and compositions for removing metal oxides
US9212555B2 (en) 2005-10-14 2015-12-15 Mtu Aero Engines Gmbh Method for removing the coating from a gas turbine component

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP6101832B2 (ja) * 2016-02-16 2017-03-22 三菱重工業株式会社 酸性水溶液の使用可否判断方法

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4443268A (en) * 1981-11-12 1984-04-17 The Dow Chemical Company Process for removing copper and copper oxide encrustations from ferrous surfaces
EP0165104A1 (fr) * 1984-05-17 1985-12-18 Societe Nationale D'etude Et De Construction De Moteurs D'aviation, "S.N.E.C.M.A." Procédé de réparation par diffusion
EP0257671A1 (fr) * 1986-07-25 1988-03-02 Solvay Procédé pour éliminer un revêtement comprenant du niobium sur un substrat
EP0354463A2 (fr) * 1988-08-06 1990-02-14 Fujitsu Limited Méthode d'attaque sèche pour métaux réfractaires et leurs composés

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS6353266A (ja) * 1986-08-22 1988-03-07 Hitachi Ltd サイドシ−ル装置

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4443268A (en) * 1981-11-12 1984-04-17 The Dow Chemical Company Process for removing copper and copper oxide encrustations from ferrous surfaces
EP0165104A1 (fr) * 1984-05-17 1985-12-18 Societe Nationale D'etude Et De Construction De Moteurs D'aviation, "S.N.E.C.M.A." Procédé de réparation par diffusion
EP0257671A1 (fr) * 1986-07-25 1988-03-02 Solvay Procédé pour éliminer un revêtement comprenant du niobium sur un substrat
EP0354463A2 (fr) * 1988-08-06 1990-02-14 Fujitsu Limited Méthode d'attaque sèche pour métaux réfractaires et leurs composés

Cited By (7)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO1999024642A1 (fr) * 1997-11-10 1999-05-20 Balzers Hochvakuum Ag Procede pour l'enlevement de couches sur des corps
US6432219B1 (en) 1997-11-10 2002-08-13 Unakis Trading Ag Method for separating layers from articles
WO1999064646A1 (fr) * 1998-06-11 1999-12-16 Unaxis Trading Ag Procede pour enlever des couches de substance dure
US6706122B2 (en) 1998-06-11 2004-03-16 Unaxis Trading Ag Method for removing layers of hard material
RU2156322C2 (ru) * 1998-07-21 2000-09-20 Акционерное общество открытого типа "Уральский завод гражданской авиации" Состав для очистки металлических поверхностей
US7611588B2 (en) 2004-11-30 2009-11-03 Ecolab Inc. Methods and compositions for removing metal oxides
US9212555B2 (en) 2005-10-14 2015-12-15 Mtu Aero Engines Gmbh Method for removing the coating from a gas turbine component

Also Published As

Publication number Publication date
EP0506928A1 (fr) 1992-10-07
DE69113020T2 (de) 1996-04-18
DE69113020D1 (de) 1995-10-19
JP2989265B2 (ja) 1999-12-13
CA2071944A1 (fr) 1992-04-20
EP0506928B1 (fr) 1995-09-13
CA2071944C (fr) 1998-02-03
JPH05503320A (ja) 1993-06-03

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