EP1266981A1 - Anticorrosive agent for stainless steel and method of anticorrosive treatment of stainless steel - Google Patents

Anticorrosive agent for stainless steel and method of anticorrosive treatment of stainless steel Download PDF

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Publication number
EP1266981A1
EP1266981A1 EP01915719A EP01915719A EP1266981A1 EP 1266981 A1 EP1266981 A1 EP 1266981A1 EP 01915719 A EP01915719 A EP 01915719A EP 01915719 A EP01915719 A EP 01915719A EP 1266981 A1 EP1266981 A1 EP 1266981A1
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Prior art keywords
stainless steel
treatment
anticorrosive
specimen
hydroxylamine
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EP01915719A
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German (de)
French (fr)
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EP1266981A4 (en
Inventor
Naoshi Imai
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Nissin Chemicals Co Ltd
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Nissin Chemicals Co Ltd
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    • 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
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/05—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions
    • C23C22/06—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6
    • C23C22/48—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals using aqueous solutions using aqueous acidic solutions with pH less than 6 not containing phosphates, hexavalent chromium compounds, fluorides or complex fluorides, molybdates, tungstates, vanadates or oxalates
    • C23C22/50—Treatment of iron or alloys based thereon
    • 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
    • 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
    • C23C22/00—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals
    • C23C22/73—Chemical surface treatment of metallic material by reaction of the surface with a reactive liquid, leaving reaction products of surface material in the coating, e.g. conversion coatings, passivation of metals characterised by the process

Definitions

  • the present invention relates to an anticorrosive agent for a surface of a stainless steel article and an anticorrosive treatment using the same.
  • the invention relates to an anticorrosive agent for a surface of a stainless steel article and an anticorrosive treatment using the same which are effectively utilizable under severe conditions.
  • a surface of metal article can be converted to have a corrosion-resistant coating or increased corrosion resistance by treating the surface with an inorganic or organic corrosion inhibitor.
  • a hydroxylamine salt (NH 2 OH ⁇ A, in which A is an acid such as H 2 SO 4 , H 3 PO 4 , or HCl) can be prepared, for example, by reacting sodium hydrogensulfite and sodium nitrate in an aqueous solution to obtain an aqueous sodium hydroxylamine disulfonate solution, and hydrolyzing the sodium hydroxylamine disulfonate.
  • the hydroxylamine salt is stable in the solid form or in an aqueous solution.
  • the hydroxylamine salt per se is generally employed as a starting material in chemical reactions. It is also used for leaving or preparing a highly chemically unstable free hydroxylamine which is of value as a chemical compound or for processing or washing electronic materials, when it is required.
  • a metal such as iron or zinc can be made to have improved corrosion resistance by placing the metal in contact with an aqueous iron phosphate or zinc phosphate solution, respectively, and forming on the metal surface a phosphate coat and that the formation of phosphate coat is enhanced by addition of several weight % of a hydroxylamine salt such as hydroxylamine sulfate into the aqueous phosphate solution.
  • the present invention provides an anticorrosive agent and an anticorrosive treating method which are effective to enhance corrosive resistance of stainless steel under severe conditions.
  • the present inventors have studied for discovering an anticorrosive agent and anticorrosive treating method which does not cause corrosion of stainless steel under severe acidic or alkaline conditions for long period of time. As a result, they have discovered that a surface of stainless steel is converted into a highly anticorrosive surface when it is heated in an aqueous hydroxylamine solution.
  • the present invention has been made upon the discovery.
  • the present invention resides in an anticorrosive agent for stainless steel surface which comprises a hydroxylamine salt.
  • the invention further resides in a method for anti-corrosive treatment which comprises heating a stainless steel surface to a temperature of 50°C or higher in contact with the above-mentioned hydroxylamine salt anticorrosive agent.
  • the hydroxylamine salt anticorrosive agent of the invention generally is in the form of an aqueous solution.
  • concentration is in the range of 0.2 to 50 wt.%, preferably in the range of 5 to 20 wt.%.
  • examples of the hydroxylamine salts include hydroxylamine sulfate, hydroxylamine phosphate, and hydroxylamine hydrochloride. Particularly preferred are hydroxylamine sulfate and hydroxylamine phosphate. These hydroxylamine salts can be prepared by known methods, as described hereinbefore.
  • an article of stainless steel can be prevented from corrosion by keeping the article in contact with a heated aqueous solution of a hydroxylamine salt.
  • the aqueous hydroxylamine salt solution is preferably heated to a temperature of 50°C or higher. If the article of stainless steel is kept into contact with an heated hydroxylamine salt solution in an pressure-resistant reaction vessel such as an autoclave, the temperature can be 100°C or higher. Generally, the temperature is kept in the range of 60 to 160°C.
  • the stainless steel article is kept in contact with the heated hydroxylamine salt solution, preferably for a period of 3 minutes or longer, more preferably 1 to 20 hours.
  • the method of the present invention is preferably applied to anticorrosive treatment of stainless steel containing chromium element and nickel element.
  • the anticorrosive treatment of the invention can effectively prevent corrosion of stainless steel under severe conditions and obviate migration of impurities of corrosion products. For instance, if a distillation apparatus made of stainless steel (employed for obtaining an aqueous hydroxylamine solution of increased purity, which is of value for preparing pharmaceutically active compound or of value as a detergent for washing electronic parts) is previously treated by the above-mentioned anticorrosive treatment, the corrosion of the apparatus by the highly corrosive hydroxylamine is effectively obviated, and migration of the impurities from the apparatus is effectively avoided.
  • an aqueous hydroxylamine phosphate solution (concentration: 20 wt.%) was placed.
  • a specimen of stainless steel having the below-mentioned alloy composition was placed in the aqueous hydroxylamine phosphate solution.
  • the flask was then placed on an oil bath heated to approx. 100°C, for 8 hours or 24 hours, for performing anti-corrosive treatment.
  • Example 2 The procedures of Example 1 were repeated except for replacing the aqueous hydroxylamine phosphate solution with an aqueous hydroxylamine sulfate solution (concentration: 20 wt.%).
  • the treatment was additionally performed for 8 hours, 24 hours, or 72 hours.
  • an aqueous hydroxylamine sulfate solution (concentration: 20 wt.%) was placed.
  • a specimen of stainless steel (3) described in Example 1 was placed in the autoclave.
  • the autoclave was then placed on an oil bath heated to approx. 160°C, for 3 hours, for performing anti-corrosive treatment of the specimen.
  • an aqueous hydroxylamine sulfate solution (concentration: 5 wt.%) was placed.
  • a specimen of stainless steel (1) or (3) described in Example 1 was placed in the autoclave.
  • the autoclave was then placed on an oil bath heated to approx. 160°C, for 8 hours, for performing anti-corrosive treatment of the specimen.
  • the specimens of stainless steel having been treated with an aqueous hydroxylamine salt solution according to the present invention keep their weights even after they are placed in a heated aqueous sulfuric acid solution for several ten hours or several hundred hours.
  • the equivalent specimens of stainless steel having been subjected to no anti-corrosive treatment loss their weights within one to 24 hrs.
  • the untreated specimens show blacken surface or give bubble formation within a short period of time.
  • the anticorrosive agent and anticorrosive treatment of the invention are effective for keeping stainless steel from corrosion.
  • the anticorrosive agent of the invention which comprises a hydroxylamine salt is of value to prominently enhance resistance to corrosion of stainless steel, particularly chromium-containing stainless steel. Further, the method of anticorrosive treatment according to the invention keeps stainless steel placed under severe conditions such as acidic or alkaline conditions for a long period of time from corrosion. This means that migration of impurities of corrosion products and their contamination is effectively avoided.

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

Abstract

An anticorrosive agent for a stainless steel surface comprising a hydroxylamine salt; a method of anticorrosive treatment of a stainless steel surface which comprises contacting the stainless steel surface with an aqueous solution of a hydroxylamine salt and heating it. The method can be employed for significantly improving the corrosion resistance of stainless steel under severe circumstances.

Description

    [Technical Field]
  • The present invention relates to an anticorrosive agent for a surface of a stainless steel article and an anticorrosive treatment using the same. Particularly, the invention relates to an anticorrosive agent for a surface of a stainless steel article and an anticorrosive treatment using the same which are effectively utilizable under severe conditions.
  • It is known that a surface of metal article can be converted to have a corrosion-resistant coating or increased corrosion resistance by treating the surface with an inorganic or organic corrosion inhibitor.
  • It is known that among metals a stainless steel containing chromium shows high resistance to corrosion. However, even such stainless steel is gradually corroded on its surface when it is kept under strong acidic or alkaline condition, or when it is placed under weak acidic or alkaline condition for a long period of time. The corrosion causes damage of the stainless steel. Further, if stainless steel is employed as material for making a reaction vessel (to be used for performing chemical reaction) or storage vessel, the corrosion products migrate into the material in the vessel as impurities.
  • A hydroxylamine salt (NH2OH·A, in which A is an acid such as H2SO4, H3PO4, or HCl) can be prepared, for example, by reacting sodium hydrogensulfite and sodium nitrate in an aqueous solution to obtain an aqueous sodium hydroxylamine disulfonate solution, and hydrolyzing the sodium hydroxylamine disulfonate. The hydroxylamine salt is stable in the solid form or in an aqueous solution. The hydroxylamine salt per se is generally employed as a starting material in chemical reactions. It is also used for leaving or preparing a highly chemically unstable free hydroxylamine which is of value as a chemical compound or for processing or washing electronic materials, when it is required.
  • As an anticorrosive treatment of iron or the like, there is known a phosphate treatment which is performed by treating a metal surface with an aqueous acidic phosphate solution. For instance, United States Patents No. 4,149,909, No. 4,865,653, and No. 5,597,465; Published EP Applications No. 0 695 817 A1 and No. 0 315 059 A1; WO 93/03198; and WO 93/20259 teach that a metal such as iron or zinc can be made to have improved corrosion resistance by placing the metal in contact with an aqueous iron phosphate or zinc phosphate solution, respectively, and forming on the metal surface a phosphate coat and that the formation of phosphate coat is enhanced by addition of several weight % of a hydroxylamine salt such as hydroxylamine sulfate into the aqueous phosphate solution.
  • The present invention provides an anticorrosive agent and an anticorrosive treating method which are effective to enhance corrosive resistance of stainless steel under severe conditions.
    • [Disclosure of Invention]
  • The present inventors have studied for discovering an anticorrosive agent and anticorrosive treating method which does not cause corrosion of stainless steel under severe acidic or alkaline conditions for long period of time. As a result, they have discovered that a surface of stainless steel is converted into a highly anticorrosive surface when it is heated in an aqueous hydroxylamine solution. The present invention has been made upon the discovery.
  • The present invention resides in an anticorrosive agent for stainless steel surface which comprises a hydroxylamine salt.
  • The invention further resides in a method for anti-corrosive treatment which comprises heating a stainless steel surface to a temperature of 50°C or higher in contact with the above-mentioned hydroxylamine salt anticorrosive agent.
  • Preferred embodiments of the hydroxylamine salt anticorrosive agent for stainless steel surface according to the invention are described below.
  • (1) The hydroxylamine salt is hydroxylamine sulfate or hydroxylamine phosphate.
  • (2) The anticorrosive agent comprising 0.2 to 50 wt.% of a hydroxylamine salt.
    • [Preferred Embodiments for Performing Invention]
  • The hydroxylamine salt anticorrosive agent of the invention generally is in the form of an aqueous solution. The concentration is in the range of 0.2 to 50 wt.%, preferably in the range of 5 to 20 wt.%. Examples of the hydroxylamine salts include hydroxylamine sulfate, hydroxylamine phosphate, and hydroxylamine hydrochloride. Particularly preferred are hydroxylamine sulfate and hydroxylamine phosphate. These hydroxylamine salts can be prepared by known methods, as described hereinbefore.
  • In the method, an article of stainless steel can be prevented from corrosion by keeping the article in contact with a heated aqueous solution of a hydroxylamine salt. The aqueous hydroxylamine salt solution is preferably heated to a temperature of 50°C or higher. If the article of stainless steel is kept into contact with an heated hydroxylamine salt solution in an pressure-resistant reaction vessel such as an autoclave, the temperature can be 100°C or higher. Generally, the temperature is kept in the range of 60 to 160°C. The stainless steel article is kept in contact with the heated hydroxylamine salt solution, preferably for a period of 3 minutes or longer, more preferably 1 to 20 hours.
  • There are no limitations with respect to stainless steel which can be treated by the method of the invention. But, the method of the present invention is preferably applied to anticorrosive treatment of stainless steel containing chromium element and nickel element.
  • The anticorrosive treatment of the invention can effectively prevent corrosion of stainless steel under severe conditions and obviate migration of impurities of corrosion products. For instance, if a distillation apparatus made of stainless steel (employed for obtaining an aqueous hydroxylamine solution of increased purity, which is of value for preparing pharmaceutically active compound or of value as a detergent for washing electronic parts) is previously treated by the above-mentioned anticorrosive treatment, the corrosion of the apparatus by the highly corrosive hydroxylamine is effectively obviated, and migration of the impurities from the apparatus is effectively avoided.
    • [Example 1]
  • In a glass-made flask equipped with a reflux condenser, an aqueous hydroxylamine phosphate solution (concentration: 20 wt.%) was placed. A specimen of stainless steel having the below-mentioned alloy composition was placed in the aqueous hydroxylamine phosphate solution.
  • The flask was then placed on an oil bath heated to approx. 100°C, for 8 hours or 24 hours, for performing anti-corrosive treatment.
  • (1) SUS 304L Stainless steel (composition: Fe approx. 73%, Ni approx. 9%, Cr approx. 18%)
  • (2) SUS 316L Stainless steel (composition: Fe approx. 70%, Ni approx. 12%, Cr approx. 16%, Mo approx. 2%)
  • (3) SUS 310S Stainless steel (composition: Fe approx. 57%, Ni approx. 19%, Cr approx. 24%)
  • Thus treated specimen was weighed, and placed in an aqueous 10 wt.% sulfuric acid solution in a heat-resistant glass bottle. The glass bottle was placed in a thermostat heated to 80°C and kept for certain periods. Then, the glass bottle was taken out from the thermostat. The specimen was recovered from the sulfuric acid solution, washed with water, dried, and weighed. Both weights were compared for determining weight loss which was caused by corrosion of the stainless steel specimen.
  • For comparison, the equivalent stainless steel specimen having no corrosion-inhibiting treatment was subjected to the above-mentioned test for evaluating the resistance in the sulfuric acid solution.
  • The results are set forth in Tables 1 to 3.
    (for SUS 304L)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of 24 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 16.4526 17.9558 18.5543
    1 -- -- 18.2378
    24 16.4523 17.9557 --
    44 16.4521 17.9556 --
    68 16.4518 17.9554 --
    116 16.4517 17.9553 --
    164 16.4513 17.9548 --
    188 16.4513 17.9548 --
    236 16.4514 17.9554 --
    284 16.4516 17.9554 --
    380 -- 17.9546 --
    529 -- 17.9544 --
    (for SUS 316L)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 18.2641 18.2103
    24 18.1244 17.6733
    44 18.0132 --
    (for SUS 310S)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 17.3690 17.5489
    1 -- 17.4191
    8 17.3690 --
    23 17.3686 --
    47 17.3687 --
    71 17.3685 --
    95 17.3688 --
    119 17.3686 --
    161 17.3684 --
    209 17.3683 --
    281 17.3685 --
    329 17.3681 --
    455 17.3679 --
    • [Example 2]
  • The procedures of Example 1 were repeated except for replacing the aqueous hydroxylamine phosphate solution with an aqueous hydroxylamine sulfate solution (concentration: 20 wt.%).
  • In the corrosion resistance-enhancing treatment, the treatment was additionally performed for 8 hours, 24 hours, or 72 hours.
  • The specimens having been subjected to anticorrosive treatment were examined in their anticorrosive performance in the same manner as in Example 1. The results are set forth in Tables 4 to 6.
    (for SUS 304L)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 15.5943 18.5543
    1 -- 18.2378
    24 15.5944 --
    44 15.5940 --
    68 15.5937 --
    116 15.5935 --
    164 15.5931 --
    188 15.5931 --
    236 15.5935 --
    284 15.5937 --
    380 15.5930 --
    529 15.5929 --
    (for SUS 316L)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 18.2045 18.2103
    24 18.0672 17.6733
    44 17.9577 --
    (for SUS 310S)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 17.7900 17.5489
    1 -- 17.4191
    8 17.7901 --
    24 17.7897 --
    47 17.7897 --
    71 17.7895 --
    95 17.7898 --
    119 17.7896 --
    167 17.7892 --
    215 17.7894 --
    287 17.7895 --
    335 17.7888 --
    455 17.7889 --
    628 17.7887 --
    (for SUS 310S)
    Time (hr.) in aq. H2SO4 Specimen of 24 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 17.9786 17.5489
    1 -- 17.4191
    24 17.9787 --
    44 17.9788 --
    68 17.9785 --
    116 17.9782 --
    164 17.9784 --
    236 17.9784 --
    284 17.9779 --
    335 17.9777 --
    (for SUS 310S)
    Time (hr.) in aq. H2SO4 Specimen of 72 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 17.5712 17.5489
    1 -- 17.4191
    19 17.5713 --
    67 17.5710 --
    115 17.5711 --
    187 17.5711 --
    235 17.5707 --
    355 17.5707 --
    528 17.5706 --
    • [Example 3]
  • In an autoclave, an aqueous hydroxylamine sulfate solution (concentration: 20 wt.%) was placed. A specimen of stainless steel (3) described in Example 1 was placed in the autoclave.
  • The autoclave was then placed on an oil bath heated to approx. 160°C, for 3 hours, for performing anti-corrosive treatment of the specimen.
  • The specimen was then placed in the aqueous sulfuric acid solution in the manner described in Example 1, to examine the corrosion resistance of thus treated specimen. The results are set forth in Table 7.
    (for SUS 310S)
    Time (hr.) in aq. H2SO4 Specimen of 3 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 17.1045 17.5489
    1 -- 17.4191
    124 17.1041 --
    • [Example 4]
  • In an autoclave, an aqueous hydroxylamine sulfate solution (concentration: 5 wt.%) was placed. A specimen of stainless steel (1) or (3) described in Example 1 was placed in the autoclave.
  • The autoclave was then placed on an oil bath heated to approx. 160°C, for 8 hours, for performing anti-corrosive treatment of the specimen.
  • The specimen was then placed in the aqueous sulfuric acid solution in the manner described in Example 1, to examine the corrosion resistance of thus treated specimen. The results are set forth in Tables 8 to 9.
    (for SUS 304L)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 17.9588 18.5543
    1 -- 18.2378
    124 17.9583 --
    (for SUS 310S)
    Time (hr.) in aq. H2SO4 Specimen of 8 hrs. treatment (weight g) Specimen of no treatment (weight g)
    0 35.5074 17.5489
    1 -- 17.4191
    124 35.5066 --
  • As is apparent from the results shown in Tables 1 to 9, the specimens of stainless steel having been treated with an aqueous hydroxylamine salt solution according to the present invention keep their weights even after they are placed in a heated aqueous sulfuric acid solution for several ten hours or several hundred hours. In contrast, the equivalent specimens of stainless steel having been subjected to no anti-corrosive treatment loss their weights within one to 24 hrs. In the aqueous sulfuric acid solution, the untreated specimens show blacken surface or give bubble formation within a short period of time.
  • Accordingly, it is clear that the anticorrosive agent and anticorrosive treatment of the invention are effective for keeping stainless steel from corrosion.
    • [Industrial Utility]
  • The anticorrosive agent of the invention which comprises a hydroxylamine salt is of value to prominently enhance resistance to corrosion of stainless steel, particularly chromium-containing stainless steel. Further, the method of anticorrosive treatment according to the invention keeps stainless steel placed under severe conditions such as acidic or alkaline conditions for a long period of time from corrosion. This means that migration of impurities of corrosion products and their contamination is effectively avoided.

Claims (5)

  1. An anticorrosive agent for stainless steel surface which comprises a hydroxylamine salt.
  2. The anticorrosive agent of claim 1, in which the hydroxylamine salt is hydroxylamine sulfate or hydroxylamine phosphate.
  3. The anticorrosive agent for stainless steel surface which comprises an aqueous solution of 0.2 to 50 weight % of a hydroxylamine salt.
  4. A method of anticorrosive treatment of stainless steel surface which comprises heating the stainless steel surface to a temperature of 50°C or higher in contact with the anticorrosive agent of any one of claims 1 to 3.
  5. The method of anticorrosive treatment of stainless steel surface, in which the heating is performed at 50 to 200°C.
EP01915719A 2000-03-24 2001-03-23 Anticorrosive agent for stainless steel and method of anticorrosive treatment of stainless steel Withdrawn EP1266981A4 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2000083529 2000-03-24
JP2000083529A JP2001271184A (en) 2000-03-24 2000-03-24 Corrosion protection treating agent and method for stainless steel
PCT/JP2001/002319 WO2001071061A1 (en) 2000-03-24 2001-03-23 Anticorrosive agent for stainless steel and method of anticorrosive treatment of stainless steel

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EP1266981A1 true EP1266981A1 (en) 2002-12-18
EP1266981A4 EP1266981A4 (en) 2006-12-27

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US (1) US20010032658A1 (en)
EP (1) EP1266981A4 (en)
JP (1) JP2001271184A (en)
KR (1) KR20030007476A (en)
CN (1) CN1429281A (en)
AU (1) AU4276401A (en)
WO (1) WO2001071061A1 (en)

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CN105694538A (en) * 2016-01-05 2016-06-22 萧县金鹭纺织品有限公司 Preparation method of low-oil-absorption-amount anticorrosion iron oxide red pigment

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HOLTZER M ET AL: "Korrosionsbestaendigkeit von Stahlguss in Hydroxilaminsulfatloesung" WERKST KORROS; WERKSTOFFE UND KORROSION NOV 1994 VCH VERLAGSGESELLSCHAF MBH, WEINHEIM, GER, vol. 45, no. 11, November 1994 (1994-11), pages 604-607, XP009073939 *
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AU4276401A (en) 2001-10-03
EP1266981A4 (en) 2006-12-27
JP2001271184A (en) 2001-10-02
CN1429281A (en) 2003-07-09
US20010032658A1 (en) 2001-10-25
WO2001071061A1 (en) 2001-09-27

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