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
  • C23G1/02—Cleaning or pickling metallic material with solutions or molten salts with acid solutions
  • C23G1/10—Other heavy metals
  • C23G1/103—Other heavy metals copper or alloys of copper

Definitions

• ABSTRACT Stabilizers are provided which control copper ioncatalyzed degradation of hydrogen peroxide.
• the H O concentration may be up to about 50% by weight, in the presence of strong inorganic nonoxidizing acids at up to about 50% by weight, and at temperatures of up to about 90C.
• Such stabilizers are included in concentrations of up to about 1.5% by weight.
• the stabilizers, at concentrations of up to about 5% by weight, may also be formulated into H 0 of up to 80% concentration by weight.
• the stabilizers are selected from the group consisting of adipic acid, glutaric acid, succinic acid, their methyl derivatives, salts, and mixtures of them.
• stabilizers selected from the group consisting of succinic, glutaric, and adipic acids, salts, methyl derivatives, and mixtures thereof, which stabilize against copper ion-induced degradation of H 0 in acidic oxidizing solutions at temperatures up to about 90C.
• the copper ions (primarily in the cupric form) may be present in concentrations of up to about 5% by weight.
• the stabilizers will function in any nonoxidizing mineral acid, sulfuric acid being the most commonly employed.
• the acid concentration may range from about 0.01 to 50% by weight, preferably about 2 to 25% by weight.
• the H 0 may be present in concentrations from about 0.01 to 80% by weight.
• These stabilizers may be formulated with H 0 and acid to form an aqueous, acidic oxidizing solution, or may preferably be included in the concentrated aqueous H 0 solution, as commercially prepared and sold, prior to adding the H 0 to the pickling bath.
• the stabilizers may be used in'any appropriate concentration; however, if the stabilizer is to be formulated into concentrated H 0 prior to addition to the pickling bath, the solubility of the stabilizer in concentrated H 0 may be the controlling factor.
• the solubility of adipic acid in 35% H 0 is only about 1% by weight. In pickling baths some stabilizing effect will be seen with as little as 0.003% stabilizer concentration.
• the usual concentration range in pickling baths will be about 0.015 to 1.5%, preferably about 0.03 to 0.1%.
• Mixtures of the stabilizers may also be used. Since adipic acid is the most effective, a mixture would preferably include it, attention being paid to the solubility considerations already noted.
• a particularly preferred mixture is the ratio of about 2 parts of succinic acid to 1 part of adipic acid.
• the stabilizer is incorporated into the concentrated aqueous H 0 as available commercially.
• a solution can be readily formulated by the H 0 manufacturer to contain at least 0.05% and as much as 5% by weight stabilizer, depending on the solubility of the stabilizer and the concentration of the H 0
• the stabilizers of this invention will be effective in any strong, nonoxidizing mineral acid solution, sulfu ric acid is of most commercial significance.
• Caros acid, an equilibration product of H 50 and H 0 may be present in the stabilized solution without detracting from the usefulness of the stabilizers.
• the H 50 concentration of a pickling bath usually is in the range of about 2 to 25% by weight, preferably 4 to 6%.
• Other nonoxidizing mineral acids may also be used in these concentration ranges.
• Such other mineral acids would include hydrochloric, hydrofluoric and phosphoric, such acids being used in the pickling of such metals as iron and aluminum and their alloys.
• Hydrogen peroxide concentration in a pickling bath typically ranges from about 0.05 to 15% by weight, preferably 0.5 to 3%, although concentrations as low as 0.01% and as high as 50% may be used. If the stabilizer is formulated into concentrated aqueous H 0 the H 0 concentration may range from about 20 to by weight, preferably about 30 to 70% more preferably about 35 to 50%. While the stabilizers of this invention may be added directly to H 0 of 70% or greater concentration, this is not recommended since solubility is lessened and there is the possibility of forming peroxyacids.
• the preferred procedure would be to dissolve the stabilizer in sufficient water that when added to the 70% H 0 the overall H 0 concentration would be reduced to a more easily handled concentration, say, 50%. Even when the stabilizer is to be added to 50% or less H 0 it is still preferred to dissolve the stabilizer in water before addition to the H 0 Any commercially available grade of H 0 may be used in this invention.
• the H 0 may be unstabilized or preferably may contain any of the usual stabilizing chemicals, e.g., sodium stannate, sodium pyrophosphate, fluosilicates, magnesium sulfate coupled with an alkylidene diphosphonic acid (as taught by U.S. Pat. No.
• stannates 0001-1 .0%, preferably 0.015-0.07%
• pyrophosphates 0.01-5.0%, preferably 0.05-4.0%
• nitrates 0.00l0.05%, preferably 0.0015-'0.04%.
• An alkylidene diphosphonic acid will preferably be present in a concentration of at least 0.1% by weight.
• the stabilizers of this invention will effectively control copper catalyzed decomposition of H 0 at temperatures up to about C. However, in most uses the typical temperature range would be about 15 to 40C.
• An aqueous, acidic, oxidizing solution stabilized against copper ion-catalyzed degradation at temperatures of up to about 90C. containing about 0.01 to 50 This example illustrates the stabilizing effect of the percent h d id b wei ht, a strong inoracids of this invention.
• ganic acid at a concentration of about 0.0] to 50 per- A solution having the following composition was precent by weight, and a stabilizing amount of a stabilizer d; selected from the group consisting of adipic acid, glum taric acid, succinic acid, and mixtures thereof. 2 5 2 5H 0 2.
• Stability will be optimized by alacid, glutaric acid, succinic acid, and mixtures thereof. lowing the pH to remain at its natural level.
• Solution Q clflim 14 wherein the hydrogen peroxide concentration 15 about 30 to 70 percent by weight.
• Table ll 16 The solution of claim 15 wherein the hydrogen peroxide concentration is about 35 to 50 percent by 3% Succinic Acid in 35% H O, weight Sample PH 7! LOSS (20 hrs at 50%..
• the solution of claim 14 wherein the stabilizer is adlplc acid. A 3.5 5.0 18.
• the solution of claim 14 wherein the stabilizer is g glutaric acid. D L5 0.6 19.
• the solution of claim 14 wherein the stabilizer is E 20 succinic acid.
• a peroxide loss of about 2% or less is considered commercially satisfactory.

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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)
• Detergent Compositions (AREA)
• ing And Chemical Polishing (AREA)
• Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)

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Cited By (24)

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Citations (4)

• 1972
  • 1972-12-04 US US311976A patent/US3864271A/en not_active Expired - Lifetime
• 1973
  • 1973-11-23 BE BE138084A patent/BE807712A/fr unknown
  • 1973-12-03 GB GB5589073A patent/GB1429819A/en not_active Expired
  • 1973-12-04 JP JP48134954A patent/JPS4988800A/ja active Pending
  • 1973-12-04 DE DE2360395A patent/DE2360395A1/de active Pending

Patent Citations (4)

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