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
  • C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
  • C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
  • C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
  • C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
  • C23F11/14—Nitrogen-containing compounds
  • C23F11/149—Heterocyclic compounds containing nitrogen as hetero atom
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
  • Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
  • Y10T428/00—Stock material or miscellaneous articles
  • Y10T428/31504—Composite [nonstructural laminate]
  • Y10T428/31678—Of metal

Definitions

• ABSTRACT A corrosion inhibiting composition which comprises an aqueous medium having dissolved therein an effective amount of at least one of water-soluble 1- hydroxybenzotriazole compounds and water-soluble salts thereof, said water-soluble l hydroxybenzotriazole compound having the formula of N n N/N wherein X and Y are respectively one member of the group consisting of hydrogen atom, a lower alkyl group having 1 to 3 carbon atoms, nitro group, halogen atom, sulfo group, methoxy group, carboxy group and cyano group.
• This invention relates to an aqueous corrosion inhibiting composition and a method for inhibiting corrosion of ferrous metals, such as iron, steel and iron alloys.
• sodium nitrate and amine-based surfactants are known as water-soluble corrosion inhibitors and have been extensively used for protecting ferrous metals from corrosion.
• such known inhibitors are not sufficient in practical uses.
• sodium nitrate displays an excellent corrosion inhibiting effect on ferrous metals which are brought into contact with water having dissolved therein said inhibitor. for example, the effect reduces markedly when ferrous metals coated with the inhibitor is placed in the air.
• the nitrite has a considerable toxicity, causing water pollution when exhausted to water system without post-treatment.
• Amine-based surfactants are insufficient in corrosion inhibiting effect in air as well as in water and will sometimes disturb cooling and washing operations due to marked foamability thereof. Ferrous metals treated with the amine-based surfactants.
• An object of the invention is to provide a composition and method for inhibiting corrosion of ferrous metals which are free from the drawbacks of the conventional inhibitors.
• Another object of the invention is to provide a corrosion inhibiting composition which displays an excellent corrosion inhibiting effect on ferrous metals not only in water but also in air.
• Another object of the invention is to provide a corrosion inhibiting composition which is low in toxicity and can be exhausted free from water pollution.
• Another object of the invention is to provide a corrosion inhibiting composition which has no foamability and therefore can be added to cooling or washing water without adversely affecting cooling or washing operationv
• Another object of the invention is to provide a corrosion inhibiting composition which makes it possible to directly subject ferrous metals treated therewith to parkerizing treatment or coating with paints.
• Another object of the invention is to provide a corrosion inhibiting composition which can be easily removed from the surface of ferrous metals treated therewith, as desired.
• the corrosion inhibiting composition of the present invention comprises an aqueous medium having dissolved therein an effective amount of at least one of water-soluble l-hydroxybenzotriazole compounds and watersoluble salts thereof, said water-soluble lhydroxybenzotriazole compound having the formula of wherein X and Y are respectively one member of the group consisting of hydrogen atom, a lower alkyl group having 1 to 3 carbon atoms, nitro group, halogen atom, sulfo group, methoxy group, carboxy group and cyano group; preferable X and Y being hydrogen atom, a lower alkyl group having 1 to 3 carbon atoms or nitro group.
• ferrous metals when ferrous metals are treated with the l-hydroxybenzotriazole and its derivatives specified above, they are effectively protected from corrosion not only in water but also in air. Such effect can not be expected from benzotriazole per se, as known in the art, which displays a corrosion inhibiting effect only on copper and its alloys but little or no effect on ferrous metals.
• ferrous metals treated with the present composition can advantageously be subjected to parkerizing treatment or coated with paint without removal of l-hydroxybenzotriazole or its derivatives therefrom.
• W hen ferrous metals treated with the present composition are to be chemically or electrically plated, lhydroxybenzotriazole or its derivatives attached thereto can easily be removed from the metal surface by simple procedures, for example, by washing with an alkali solution.
• the l-hydroxybenzotriazole and derivatives thereof to be used in the invention are l-hydroxybenzotriazole compounds having the formula (1) before and watersoluble salts thereof.
• Representative examples of the l-hydroxybenzotriazole compounds are lhydroxybenzotriazole, l-hydroxy-4-methylbenzotriazole, l-hydroxy- 6-nitro-benzotriazole, l-
• ammonium salts for example, ammonium salts, alkali metal salts, hydrazine salts and amine salts.
• l-hydroxybenzotriazole and derivatives thereof preferable are l-hydroxybenzotriazole, lhydroxy4-methyl-benzotriazole, l-hydroxy-onitrobenzotriazole and water-soluble salts thereof.
• l-hydyroxybenzotriazole compounds to be used in the invention are known in the art and can be prepared, for example by the reaction of hydrazine with o-chloronitrobenzene having or not having one or two substituents.
• Ferrous metals to which the present composition is applied include iron and its alloys such as carbon steel, mild steel, stainless steel, cast iron, etc.
• the l-hydroxybenzotriazole and derivatives thereof to be used as corrosion inhibitor in the invention are water-soluble, so that they can be applied to the ferrous metals in the manner conventional to water-soluble corrosion inhibitors.
• ferrous metals may be brought into contact with the present corrosion inhibitor by coating them with an aqueous solution of the inhibitor, followed by drying, or by adding the inhibitor to water to be brought into contact with the ferrous metals.
• the present inhibitor is added to water such as cooling water in the rolling of ferrous metals, cooling water in a cooling system, washing water for pickled or degreased ferrous metals, etc. Since the present inhibitor is thermally stable, it displays an excellent corrosion inhibiting effect in various temperature conditions, for example, in primary cooling water of near C in winter as well as in cooling water of about 60 to 80C in rolling operation.
• the effective concentration of the present inhibitor varies over a wide range depending on the application method, kind of ferrous metals to be treated, etc., but it displays a sufficient effect in such a small concentration as 0.05 wt.%. Since the present inhibitor has little or no toxicity, it can be used in any large amount. But it is preferable to use the inhibitor in a concentration of 0.05 to 10 weight percent from economical view point. Particularly, when the present inhibitor is used in the form of an aqueous solution for coating ferrous metals, preferable concentration of the inhibitor in solution is in the range of 0.5 to 5 weight percent.
• additives can be added to the present composition in order to improve the properties thereof.
• water-soluble high molecular weight substances are added thereto to further improve the corrosion inhibiting effect on ferrous metals.
• examples thereof are polyvinyl alcohol, polyvinyl pyrrolidone, carboxymethyl cellulose, starch, polyacrylic acid, styrene-maleic acid copolymer, etc.
• surfactants are added in order to improve wettability of ferrous metals to be treated with the present composition.
• surfactants examples include nonionic surfactants such as polyoxyethylene alkylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, etc.; cationic surfactants such as quaternary ammonium salts, etc.; anionic surfactants such as ammonium salt of alkylbenzenesulfonate, sodium salt of polyoxyethylene nonylphenyl ether sulfate, etc.
• nonionic surfactants such as polyoxyethylene alkylphenyl ether, polyoxyethylene lauryl ether, polyoxyethylene oleyl ether, polyoxyethylene nonylphenyl ether, etc.
• cationic surfactants such as quaternary ammonium salts, etc.
• anionic surfactants such as ammonium salt of alkylbenzenesulfonate, sodium salt of polyoxyethylene nonylphenyl ether sulfate, etc.
• C5 is cold-rolled steel of JlS-G-3l4l. Class 1, measuring mm X mm X 1.2 mm.
• HRS hot-rolled stcel ofJlS-G-3l3l, measuring 60 mm X 80 mm X 8 mm.
• Cl is cast iron of .llS-G-SSOI. Class 3. measuring 60 mm X 80 mm X 5 mm.
• the LD as determined by Table 4 shows that the present composition is very effective in inhibiting corrosion in the surface of ferrous alloy in contact with circulating water.
• a method for inhibiting corrosion of a ferrous Litchfield Wilcoxon method was 16.330 mg/kg which is about 1/180 the LD of 85 mg/kg for sodium nitrile metal comprlss Fomammg a ferrous metal as determined in rats. This indicates that the present a composmo comammg an effecuve "P of at Composition is Very low in toxicity least one of watersoluble l-hydroxybenzotnaaoie compounds and water-soluble salts thereof, said water- IV.
• Acute Toxicity Test '0 soluble l-hydroxybenzotriazole compound having the l-hydroxybenzotriazole was dissolved in water at formula varying concentrations, and ten killifishes measuring X 2.5 to 3 cm in length were placed into each solution ⁇ 5 A and raised for 24 hours.
• the median tolerance limit N (TLm) as determined according to JIS-K-OlOZ was about 800 ppm.
• the TLm for sodium nitrite as determined by the same procedure was 10 to 13 ppm.
• This H shows that the present compositions were very low in toxicity to fishes and almost free of water pollution.
• X and Y are each refsgectwely one member seected from the group consisting of hydrogen atom, a EXAMPLE 2 lower alkyl group having 1 to 3 carbon atoms, nitro l-hydroxybenzotriazole was dissolved in water at gggs gfig gg ggis gig g method), group car temperature, at Varying concentratlons and the 2.
• the method for inhibiting corrosion of a ferrous solutions were adjusted to pH of 3 t aOH to pr metal according to claim 1, wherein said X and Y are pare compositions of this invention.
• Example 1 (l) respectively one member selected from the group con- Containers of cold-rolled steel sheet (.llS-G-3 l4l sisting of hydrogen atom, a lower alkyl group 1 to 3 car- Class 1) polished and washed on the inner surface bOn atoms and nitro group. thereof in the same manner as in Example 1 (l) were The method for inhibiting q i of a q filled with the compositions thus prepared and sealed.
• Criteria of corrobenzotriazole 1 hydmxy 6 carboxy benzotriazole and SiOll are the same as in test Of Example 1.
• 1-hyd o y 5-isopropylbenzotriazole Table 3 Sample Concen- Corrosion No. tration 24 48 72 as 120 240 360 480 (wt.%) hrs. hrs. hrs. hrs. hrs. hrs. hrs. hrs. hrs.
• a steel tube (JlS-G-3452), 300 cm in length and 4.16 5.
• the method for inhibiting corrosion of a ferrous cm in inner diameter was washed with 5 wt.% acetic metal according to claim 1, wherein said effective acid and then with water.
• the same composition as amount is M1635 Q05 in concentration- Sample 23 m
• Example 2 was clrculatec ⁇ commu' 6.
• the results are given in Table 4. tion.
• hydroxybenzotriazole compound having the formula 0 wherein X and Y are respectively one member of the group consisting of hydrogen atom, a lower alkyl group having 1 to 3 carbons, nitro group, halogen atom, sulfo group, methoxy group, carboxy-group and cyano 5 group.

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• Chemical & Material Sciences (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Mechanical Engineering (AREA)
• Metallurgy (AREA)
• Organic Chemistry (AREA)
• Preventing Corrosion Or Incrustation Of Metals (AREA)

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Cited By (26)

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Citations (1)

• 1972
  • 1972-02-05 JP JP1304672A patent/JPS5327694B2/ja not_active Expired
• 1973
  • 1973-02-02 US US329081A patent/US3895170A/en not_active Expired - Lifetime
  • 1973-02-02 GB GB526773A patent/GB1388354A/en not_active Expired
  • 1973-02-05 IT IT67236/73A patent/IT984354B/it active
  • 1973-02-05 DE DE2305521A patent/DE2305521C3/de not_active Expired
  • 1973-02-05 FR FR7303936A patent/FR2170264B1/fr not_active Expired

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