US3880772A - Composition for ring passivation - Google Patents
Composition for ring passivation Download PDFInfo
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- US3880772A US3880772A US278867A US27886772A US3880772A US 3880772 A US3880772 A US 3880772A US 278867 A US278867 A US 278867A US 27886772 A US27886772 A US 27886772A US 3880772 A US3880772 A US 3880772A
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- United States
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- chromium
- calculated
- composition
- zinc
- boron
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- 239000000203 mixture Substances 0.000 title claims abstract description 66
- 238000002161 passivation Methods 0.000 title abstract description 13
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 claims abstract description 40
- 229910052725 zinc Inorganic materials 0.000 claims abstract description 40
- 239000011701 zinc Substances 0.000 claims abstract description 40
- VYZAMTAEIAYCRO-UHFFFAOYSA-N Chromium Chemical compound [Cr] VYZAMTAEIAYCRO-UHFFFAOYSA-N 0.000 claims abstract description 31
- 229910052804 chromium Inorganic materials 0.000 claims abstract description 31
- 239000011651 chromium Substances 0.000 claims abstract description 31
- ZOXJGFHDIHLPTG-UHFFFAOYSA-N Boron Chemical compound [B] ZOXJGFHDIHLPTG-UHFFFAOYSA-N 0.000 claims abstract description 22
- 229910052796 boron Inorganic materials 0.000 claims abstract description 22
- JOPOVCBBYLSVDA-UHFFFAOYSA-N chromium(6+) Chemical class [Cr+6] JOPOVCBBYLSVDA-UHFFFAOYSA-N 0.000 claims abstract description 17
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical class O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 claims abstract description 16
- 150000001845 chromium compounds Chemical class 0.000 claims abstract description 12
- 150000001875 compounds Chemical class 0.000 claims abstract description 10
- 150000001639 boron compounds Chemical class 0.000 claims abstract description 7
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 claims description 10
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 claims description 10
- 229910052790 beryllium Inorganic materials 0.000 claims description 10
- 229910052700 potassium Inorganic materials 0.000 claims description 10
- 239000011591 potassium Substances 0.000 claims description 10
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 claims description 9
- WHXSMMKQMYFTQS-UHFFFAOYSA-N Lithium Chemical compound [Li] WHXSMMKQMYFTQS-UHFFFAOYSA-N 0.000 claims description 9
- FYYHWMGAXLPEAU-UHFFFAOYSA-N Magnesium Chemical compound [Mg] FYYHWMGAXLPEAU-UHFFFAOYSA-N 0.000 claims description 9
- ATBAMAFKBVZNFJ-UHFFFAOYSA-N beryllium atom Chemical compound [Be] ATBAMAFKBVZNFJ-UHFFFAOYSA-N 0.000 claims description 9
- 229910052744 lithium Inorganic materials 0.000 claims description 9
- 239000011777 magnesium Substances 0.000 claims description 9
- 229910052749 magnesium Inorganic materials 0.000 claims description 9
- 229910017604 nitric acid Inorganic materials 0.000 claims description 9
- 150000003839 salts Chemical class 0.000 claims description 9
- 239000011734 sodium Substances 0.000 claims description 9
- 229910052708 sodium Inorganic materials 0.000 claims description 9
- 229910052793 cadmium Inorganic materials 0.000 claims description 6
- BDOSMKKIYDKNTQ-UHFFFAOYSA-N cadmium atom Chemical compound [Cd] BDOSMKKIYDKNTQ-UHFFFAOYSA-N 0.000 claims description 6
- 229940117975 chromium trioxide Drugs 0.000 claims description 6
- WGLPBDUCMAPZCE-UHFFFAOYSA-N chromium trioxide Inorganic materials O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 claims description 6
- GAMDZJFZMJECOS-UHFFFAOYSA-N chromium(6+);oxygen(2-) Chemical compound [O-2].[O-2].[O-2].[Cr+6] GAMDZJFZMJECOS-UHFFFAOYSA-N 0.000 claims description 6
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 claims description 5
- 235000010338 boric acid Nutrition 0.000 claims description 5
- 229960002645 boric acid Drugs 0.000 claims description 5
- 150000002823 nitrates Chemical class 0.000 claims description 5
- NFMWFGXCDDYTEG-UHFFFAOYSA-N trimagnesium;diborate Chemical compound [Mg+2].[Mg+2].[Mg+2].[O-]B([O-])[O-].[O-]B([O-])[O-] NFMWFGXCDDYTEG-UHFFFAOYSA-N 0.000 claims description 4
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical class [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 claims description 3
- 235000015217 chromium(III) sulphate Nutrition 0.000 claims description 2
- 238000005555 metalworking Methods 0.000 abstract description 2
- 239000000243 solution Substances 0.000 description 19
- 238000005260 corrosion Methods 0.000 description 15
- 230000007797 corrosion Effects 0.000 description 15
- 238000000034 method Methods 0.000 description 11
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- WKNIDMJWLWUOMZ-UHFFFAOYSA-N [K].[Cr] Chemical compound [K].[Cr] WKNIDMJWLWUOMZ-UHFFFAOYSA-N 0.000 description 4
- 230000000694 effects Effects 0.000 description 4
- 229940050271 potassium alum Drugs 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 238000012360 testing method Methods 0.000 description 4
- 230000007935 neutral effect Effects 0.000 description 3
- 239000011780 sodium chloride Substances 0.000 description 3
- PAWQVTBBRAZDMG-UHFFFAOYSA-N 2-(3-bromo-2-fluorophenyl)acetic acid Chemical compound OC(=O)CC1=CC=CC(Br)=C1F PAWQVTBBRAZDMG-UHFFFAOYSA-N 0.000 description 2
- 239000002253 acid Substances 0.000 description 2
- RFVVBBUVWAIIBT-UHFFFAOYSA-N beryllium nitrate Chemical compound [Be+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O RFVVBBUVWAIIBT-UHFFFAOYSA-N 0.000 description 2
- 239000004327 boric acid Substances 0.000 description 2
- 238000005282 brightening Methods 0.000 description 2
- 238000005266 casting Methods 0.000 description 2
- 239000003795 chemical substances by application Substances 0.000 description 2
- PHFQLYPOURZARY-UHFFFAOYSA-N chromium trinitrate Chemical compound [Cr+3].[O-][N+]([O-])=O.[O-][N+]([O-])=O.[O-][N+]([O-])=O PHFQLYPOURZARY-UHFFFAOYSA-N 0.000 description 2
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 description 2
- JQVALDCWTQRVQE-UHFFFAOYSA-N dilithium;dioxido(dioxo)chromium Chemical class [Li+].[Li+].[O-][Cr]([O-])(=O)=O JQVALDCWTQRVQE-UHFFFAOYSA-N 0.000 description 2
- 238000007598 dipping method Methods 0.000 description 2
- YIXJRHPUWRPCBB-UHFFFAOYSA-N magnesium nitrate Chemical compound [Mg+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O YIXJRHPUWRPCBB-UHFFFAOYSA-N 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- PXLIDIMHPNPGMH-UHFFFAOYSA-N sodium chromate Chemical class [Na+].[Na+].[O-][Cr]([O-])(=O)=O PXLIDIMHPNPGMH-UHFFFAOYSA-N 0.000 description 2
- VWDWKYIASSYTQR-UHFFFAOYSA-N sodium nitrate Chemical compound [Na+].[O-][N+]([O-])=O VWDWKYIASSYTQR-UHFFFAOYSA-N 0.000 description 2
- ONDPHDOFVYQSGI-UHFFFAOYSA-N zinc nitrate Chemical compound [Zn+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O ONDPHDOFVYQSGI-UHFFFAOYSA-N 0.000 description 2
- 239000000956 alloy Substances 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- FEIXNIOTSKFSAZ-UHFFFAOYSA-L azane;dihydroxy(dioxo)chromium Chemical class N.N.O[Cr](O)(=O)=O FEIXNIOTSKFSAZ-UHFFFAOYSA-L 0.000 description 1
- -1 beryllium chromates Chemical class 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- XIEPJMXMMWZAAV-UHFFFAOYSA-N cadmium nitrate Inorganic materials [Cd+2].[O-][N+]([O-])=O.[O-][N+]([O-])=O XIEPJMXMMWZAAV-UHFFFAOYSA-N 0.000 description 1
- GLPMHULIKFGNIJ-UHFFFAOYSA-N cadmium(2+);dioxido(dioxo)chromium Chemical class [Cd+2].[O-][Cr]([O-])(=O)=O GLPMHULIKFGNIJ-UHFFFAOYSA-N 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- AUTNMGCKBXKHNV-UHFFFAOYSA-P diazanium;3,7-dioxido-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane Chemical compound [NH4+].[NH4+].O1B([O-])OB2OB([O-])OB1O2 AUTNMGCKBXKHNV-UHFFFAOYSA-P 0.000 description 1
- SOCTUWSJJQCPFX-UHFFFAOYSA-N dichromate(2-) Chemical compound [O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O SOCTUWSJJQCPFX-UHFFFAOYSA-N 0.000 description 1
- PSHMSSXLYVAENJ-UHFFFAOYSA-N dilithium;[oxido(oxoboranyloxy)boranyl]oxy-oxoboranyloxyborinate Chemical compound [Li+].[Li+].O=BOB([O-])OB([O-])OB=O PSHMSSXLYVAENJ-UHFFFAOYSA-N 0.000 description 1
- UQGFMSUEHSUPRD-UHFFFAOYSA-N disodium;3,7-dioxido-2,4,6,8,9-pentaoxa-1,3,5,7-tetraborabicyclo[3.3.1]nonane Chemical compound [Na+].[Na+].O1B([O-])OB2OB([O-])OB1O2 UQGFMSUEHSUPRD-UHFFFAOYSA-N 0.000 description 1
- 238000004090 dissolution Methods 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- CRGGPIWCSGOBDN-UHFFFAOYSA-N magnesium;dioxido(dioxo)chromium Chemical class [Mg+2].[O-][Cr]([O-])(=O)=O CRGGPIWCSGOBDN-UHFFFAOYSA-N 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- NMHMNPHRMNGLLB-UHFFFAOYSA-N phloretic acid Chemical compound OC(=O)CCC1=CC=C(O)C=C1 NMHMNPHRMNGLLB-UHFFFAOYSA-N 0.000 description 1
- 238000005498 polishing Methods 0.000 description 1
- XMXNVYPJWBTAHN-UHFFFAOYSA-N potassium chromate Chemical class [K+].[K+].[O-][Cr]([O-])(=O)=O XMXNVYPJWBTAHN-UHFFFAOYSA-N 0.000 description 1
- KIEOKOFEPABQKJ-UHFFFAOYSA-N sodium dichromate Chemical compound [Na+].[Na+].[O-][Cr](=O)(=O)O[Cr]([O-])(=O)=O KIEOKOFEPABQKJ-UHFFFAOYSA-N 0.000 description 1
- 235000010344 sodium nitrate Nutrition 0.000 description 1
- 239000004317 sodium nitrate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- NDKWCCLKSWNDBG-UHFFFAOYSA-N zinc;dioxido(dioxo)chromium Chemical class [Zn+2].[O-][Cr]([O-])(=O)=O NDKWCCLKSWNDBG-UHFFFAOYSA-N 0.000 description 1
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
- 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
- C23C22/24—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 containing hexavalent chromium compounds
- C23C22/30—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 containing hexavalent chromium compounds containing also trivalent chromium
Definitions
- trivalent chromium compound (as calculated for chromium): 5.0-20.0 hexavalent chromium compound (as calculated for chromium): 0.1-2.0 nitric acid salt (as calculated for N0 10.0-25.0 boron-containing compound (as calculated for boron): 1.8-6.0
- the invention is applicable in metal-working industry.
- the present invention relates to finishing metal parts and has particular reference to a dry composition for the preparation of a solution for bright dipping and colourless passivation of zinc to increase the anticorrosive properties of the zinc-coated parts such as zinc-based alloys, zinc casting, and especially zinc-plated parts.
- Zinc is known to rapidly corrode under the effects of atmospheric moisture. In order to lengthen the service life and preserve the esthetic appearance of zinccoated parts, such parts may be passivated in acid solutions of trior hexavalent chromium. Prior art liquid aqueous solutions are known for the colourless zinc; passivation which comprise a trivalent chromium compound and nitric acid, or triand hexavalent chromium compounds.
- Said methods are instrumental in obtaining colourless ornamental films on the zinc surface.
- incipient traces of corrosion on the zinc surface when tested with a S-percent neutral solution of sodium chloride are found to appear as early as within 10-20 hours of the test period.
- hexavalent chromium compound (as calculated for chromium): 0.1-2.0; nitric acid salt (as calculated for N 10.0-25.0; boron compound (as calculated for boron): 1.8-6.0.
- Trivalent chromium compounds are the principal passivating agent. In the present zinc-passivating composition trivalent chromium must be present in an amount of from 50-200 weight parts.
- a hexavalent chromium compound is an auxiliary passivating substance; its concentration in the passivating composition must be within 0.1 to 2.0 weight parts.
- Nitric acid salts render oxidating and brightening effects; their concentration in the composition, as calculated the N0 ions is to be maintained within 10.0 to 25.0 weight parts.
- the boron compounds impart polishing and brightening properties to the present composition; their concentration in the zinc-passivating compositions of the invention, as calculated for boron, should be within 1.8 to 6.0 weight parts.
- One of the optimum variants of the colourless zinc passivating composition may one incorporating the following constituents (parts by weight):
- cording to the invention is essentially a mixture of tri- H O. etc. for instance.
- chromium trioxide ammonium chromates. beryllium chromates. potassium chromates, cadmium chromates, lithium chromates, magnesium chromates, sodium chromates, zinc chromates, bichromates of ammonium, beryllium, potassium, cadmium, lithium, magnesium, sodium, zinc. or mixtures of the afore-mentioned compounds may be used.
- the nitric acid salts present in the proposed zincpassivating composition may be nitrates of ammonium, beryllium, potassium, cadmium, lithium, magnesium. sodium, zinc, or as mixtures of the abovesaid salts.
- the sources of boron compounds may be orthoboric acid, magnesium orthoborate, polyborates of ammonium, beryllium, potassium, lithium, magnesium, sodium, as well as a diversity of combinations of the abovementioned compounds.
- the proposed zinc-passivating composition is a mixture of non-volatile solid chemicals and therefore is distinguished for by its simplicity of preparation, transportation, storage and application.
- the preparations simplicity resides in an easily obtained passivating solution, and correction and control of the composition thereof. Correction of the passivating solution during its use consists in merely adding chemicals to the zincpassivatin g composition.
- the present zinc-passivating composition may be prepared, in case of necessity, by conventional mechanical intermixing of the parent components thereof at the site of application.
- the resultant colourless passive films possess good corrosion resistance.
- the incipient traces of corrosion on a zinc surface exposed to the effects of a S-percent neutral solution of sodium chloride at 35 1 1C may 1 appear only after from 40-60 testing hours.
- passivation may be carried out in manual or automatic plants of both the stationary or the rotary type.
- the passivating composition is prepared by thoroughly mixing the parent substances until a homogeneous mass is obtained. Then the zinc-passivating composition is dissolved in a definite amount of distilled or de- 7 ionized water taking into consideration that the concentration of the trivalent chromium in the resultant passivating solution should be from 3-6 g/l. Acidity of the freshly prepared solution should be within the pH value of 2.1 i 0.3; during the operation the acidity may be corrected by adding some acid, e.g., sulphuric.
- Objects made from the fine (unalloyed) zinc or zinc casting, or zinc plated are passivated by dipping or spraying same for from 10120s, optimum 30 s at a temperature of to 35C, optimum C, washed with water and dried.
- a zinc-passivating composition is prepared containing (in parts by weight): chromium sulphate (as calculated for chromium): 10.4 chromium trioxide (as calculated for chromium): 1.1
- chromium-potassium alum (as calculated for chromium): 10.2
- chromium trioxide (as calculated for chromium): 1.0
- ammonium nitrate (as calculated for N0 10.5
- magnesium orthoborate (as calculated for boron): 4.3
- the corrosion resistance time of the zinc surface as
- Example 3 Following the conditions of Example 1 following passivating composition was prepared (in party by weight): chromium nitrate (as calculated for chromium): 10.0 chromium-potassium alum (as calculated for chromium): 10.0 sodium monochromate (as calculated for chromium):
- EXAMPLE 4 Following the conditions of Example 1. the following passivating composition was prepared (in parts by weight): chromium-potassium alum (as calculated for chromium): 5.0 potassium mono'chromate (as calculated for chromium): 2.0 cadmium nitrate (as calculated for N0 10.0 boric acid (as calculated for boron): 6.0
- EXAMPLE 5 Following the conditions of Example 1. the following passivating composition was prepared (in parts by weight): chromium-potassium alum (as calculated for chromium): 8.0 sodiumbichromate (as calculated for chromium): 1.0 beryllium nitrate (as calculated for N0 25.0 sodium tetraborate (as calculated for boron): 1.8
- EXAMPLE 6 Following the conditions of Example 1, the following passivating composition was prepared (in parts by weight): chromium sulphate (as calculated for chromium): 10.5 lithium chromate (as calculated for chromium): 0.5 ammonium bichromate (as calculated for chromium):
- a composition for passivating zinc comprising a mixture of the following components, in parts by weight of from 5.0 to 20.0 of trivalent chromium compounds, as calculated for the chromium; from 0.1-2.0 hexavalent chromium, as calculated for the chromium; from 10.0 to 25.0 of inorganic salts of nitric acid, as
- composition for passivating zinc as claimed in claim 1 wherein the mixture comprises a mixture. in parts by weight, of from 8.0 to 13.0 of trivalent chromium compounds, as calculated for the chromium; from 0.7 1.1 of hexavalent chromium, as calculated for the chromium; from 13.0 to 16.0 of of inorganic salts of nitric acid, as calculated for N0 and from 2.5 to 4.5 of boron containing compounds, as calculated for the boron.
- composition for passivating zinc wherein the mixture consists essentially of the components as claimed in claim 1, and wherein the salts of nitric acid are selected from the group consisting of nitrates of ammonium, of beryllium, of potassium, of cadmium, of lithium, of magnesium, of sodium, of zinc, and of mixtures of said salts.
- composition as claimed in claim 4, wherein the boron component is selected from the group consisting of orthoboric acid, magnesium orthoborate, polyborates of ammonium, beryllium, potassium, lithium, magnesium, sodium, and mixtures thereof.
- composition as claimed in claim 1, wherein the trivalent chromium component is selected from the group consisting of chromic sulfates, chromic nitrates, and mixtures thereof.
- composition as claimed in claim 1, wherein the hexavalent chromium component is selected from the group consisting of chromium trioxide; the chromates and bichromates of ammonium, beryllium, potassium, cadmium, sodium, magnesium, lithium, and
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- Chemical & Material Sciences (AREA)
- General Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Engineering & Computer Science (AREA)
- Materials Engineering (AREA)
- Mechanical Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Treatment Of Metals (AREA)
Abstract
A composition for zinc passivation is essentially a mixture of trivalent chromium compounds, hexavalent chromium compounds, nitric acid salts and boron compounds, contained in the following amounts (in parts by weight): TRIVALENT CHROMIUM COMPOUND (AS CALCULATED FOR CHROMIUM): 5.020.0 HEXAVALENT CHROMIUM COMPOUND (AS CALCULATED FOR CHROMIUM): 0.12.0 NITRIC ACID SALT (AS CALCULATED FOR NO3 ): 10.0-25.0 boron-containing compound (as calculated for boron): 1.8-6.0 The invention is applicable in metal-working industry.
Description
United States Patent [191 Rekertas et a1.
11] 3,880,772 [451 Apr. 29, 1975 1 COMPOSITION FOR RING PASSIVATION [76] lnventors: Romualdes Vatslovovich Rekertas,
ulitsa V. Putny. 9, kv. 80; Romas Romovich Sharmaitis, ulitsa Antakalne, 93, kv. 24; .Iuozas Juozovich Matulis, ulitsa Maloneii 11, kv. 1, all of Vilnjus, U.S.S.R.
[22] Filed: Aug. 8, 1972 [21] Appl. No.: 278,867
[30] Foreign Application Priority Data 3.620.777 11/1971 Okabe et a1. 252/387 3.706.603 12/1972 Vesscy et a1 252/387 FOREIGN PATENTS OR APPLlCATIONS 672,751 10/1962 Canada 252/387 Primary Examiner-Benjamin R. Padgett Assistant Examiner-Irwin Gluck Attorney, Agent, or FirmHo1man & Stern [57] ABSTRACT A composition for zinc passivation is essentially a mixture of trivalent chromium compounds, hexavalent chromium compounds, nitric acid salts and boron compounds, contained in the following amounts (in parts by weight):
trivalent chromium compound (as calculated for chromium): 5.0-20.0 hexavalent chromium compound (as calculated for chromium): 0.1-2.0 nitric acid salt (as calculated for N0 10.0-25.0 boron-containing compound (as calculated for boron): 1.8-6.0
The invention is applicable in metal-working industry.
7 Claims, No Drawings COMPOSITION FOR RING PASSIVATION The present invention relates to finishing metal parts and has particular reference to a dry composition for the preparation of a solution for bright dipping and colourless passivation of zinc to increase the anticorrosive properties of the zinc-coated parts such as zinc-based alloys, zinc casting, and especially zinc-plated parts.
Zinc is known to rapidly corrode under the effects of atmospheric moisture. In order to lengthen the service life and preserve the esthetic appearance of zinccoated parts, such parts may be passivated in acid solutions of trior hexavalent chromium. Prior art liquid aqueous solutions are known for the colourless zinc; passivation which comprise a trivalent chromium compound and nitric acid, or triand hexavalent chromium compounds.
The use of a solution containing a trivalent chromium compound and nitric acid is accompanied by a substantial amount of the metal under passivation getting dissolved, especially in the case when automatic passivation plants are used. Preparation of the passivating solution and the passivation effecting procedure by said method involves great amounts of concentrated nitric acid which presents some difficulties in making said solution and in controlling the composition thereof. A ainc surface passivated in such a solution features good ornamental appearance, however, its corrosionrcsistance is improvedinsignificantly.
The use of a solution containing the compounds of triand hexavalent chromium makes it possible to obtain colourless-passive films on the surface of zinc parts, however their corrosion resistance properties is improved inconsiderably. In order to increase the corrosion resistance properties of the passive films, the hexavalent chromium content in the solution may be increased. However. introduction of large amounts of chromium trioxide results in the formation of coloured film on the zinc surface.
Said methods are instrumental in obtaining colourless ornamental films on the zinc surface. However. incipient traces of corrosion on the zinc surface when tested with a S-percent neutral solution of sodium chloride, are found to appear as early as within 10-20 hours of the test period.
It is an object of the present invention to provide a composition that would be suitable for the preparation of a solution to be used in a colourless zinc passivation process either on manual, aided or automatic plants.
It is another object of the present invention to diminish amount of zinc rendered into solution during the passivation procedure.
It is another object of the present invention to obtain ornamental'passive films which do not affect the metallic aspect of zinc.
It is still a further object of the present invention to hexavalent chromium compound (as calculated for chromium): 0.1-2.0; nitric acid salt (as calculated for N 10.0-25.0; boron compound (as calculated for boron): 1.8-6.0.
Trivalent chromium compounds are the principal passivating agent. In the present zinc-passivating composition trivalent chromium must be present in an amount of from 50-200 weight parts. A hexavalent chromium compound is an auxiliary passivating substance; its concentration in the passivating composition must be within 0.1 to 2.0 weight parts. Nitric acid salts render oxidating and brightening effects; their concentration in the composition, as calculated the N0 ions is to be maintained within 10.0 to 25.0 weight parts. The boron compounds impart polishing and brightening properties to the present composition; their concentration in the zinc-passivating compositions of the invention, as calculated for boron, should be within 1.8 to 6.0 weight parts. One of the optimum variants of the colourless zinc passivating composition may one incorporating the following constituents (parts by weight):
' trivalent chromium compound (as calculated for chroobtain colourless passive films possessing an increased corrosion resistance.
Said objects have been accomplished by the provision of a composition for zinc passivationwhich, ac-
cording to the invention, is essentially a mixture of tri- H O. etc. for instance.
As sources of the hexavalent chromium in the proposed zinc-passivating composition chromium trioxide, ammonium chromates. beryllium chromates. potassium chromates, cadmium chromates, lithium chromates, magnesium chromates, sodium chromates, zinc chromates, bichromates of ammonium, beryllium, potassium, cadmium, lithium, magnesium, sodium, zinc. or mixtures of the afore-mentioned compounds may be used.
The nitric acid salts present in the proposed zincpassivating composition may be nitrates of ammonium, beryllium, potassium, cadmium, lithium, magnesium. sodium, zinc, or as mixtures of the abovesaid salts.
The sources of boron compounds may be orthoboric acid, magnesium orthoborate, polyborates of ammonium, beryllium, potassium, lithium, magnesium, sodium, as well as a diversity of combinations of the abovementioned compounds.
The proposed zinc-passivating composition is a mixture of non-volatile solid chemicals and therefore is distinguished for by its simplicity of preparation, transportation, storage and application. The preparations simplicity resides in an easily obtained passivating solution, and correction and control of the composition thereof. Correction of the passivating solution during its use consists in merely adding chemicals to the zincpassivatin g composition.
The present zinc-passivating composition may be prepared, in case of necessity, by conventional mechanical intermixing of the parent components thereof at the site of application.
The resultant colourless passive films possess good corrosion resistance. The incipient traces of corrosion on a zinc surface exposed to the effects of a S-percent neutral solution of sodium chloride at 35 1 1C may 1 appear only after from 40-60 testing hours.
gattrition, therefore passivation may be carried out in manual or automatic plants of both the stationary or the rotary type. I
The application of the proposed composition is carried out as follows.
The passivating composition is prepared by thoroughly mixing the parent substances until a homogeneous mass is obtained. Then the zinc-passivating composition is dissolved in a definite amount of distilled or de- 7 ionized water taking into consideration that the concentration of the trivalent chromium in the resultant passivating solution should be from 3-6 g/l. Acidity of the freshly prepared solution should be within the pH value of 2.1 i 0.3; during the operation the acidity may be corrected by adding some acid, e.g., sulphuric. Objects made from the fine (unalloyed) zinc or zinc casting, or zinc plated are passivated by dipping or spraying same for from 10120s, optimum 30 s at a temperature of to 35C, optimum C, washed with water and dried.
The resultant passive film on the zinc surface is subjected to corrosion tests using the salt fog" method which consists in the continuous exposure of the pas.- sivc film to the effects of fog from the spray of a 5- percent aqueous neutral solution of sodium chloride in a test-chamber at 1C. Corrosion resistance of the film is assessed by time elapsed from the beginning of test until] the appearance of incipient corrosion traces EXAMPLE 1 I A zinc-passivating composition is prepared containing (in parts by weight): chromium sulphate (as calculated for chromium): 10.4 chromium trioxide (as calculated for chromium): 1.1
sodium nitrate (as calculated for N0 13.0 boricacid (as calculated for boron): 4.1
Further, 40 g of the thus-prepared composition are dissolved in a litre of distilled water. Upon dissolution the pH value of the solution is 1.98. A bright-zinc coated object is taken from the zinc bath immediately after washing with water and. without being brightdipped, is immersed for 30 seconds in the passivating solution, then washed with running water and air-dried. Upon drying the object shows that all surfaces are coated with a uniform colourless passive film. Corrosion of the film was resisted as determined by the saltfog method for at least 60 hours.
EXAMPLE 2 Following the conditions of Example 1 the following passivating composition was prepared (in parts by weight):
chromium-potassium alum (as calculated for chromium): 10.2
chromium trioxide (as calculated for chromium): 1.0
ammonium nitrate (as calculated for N0 10.5
magnesium nitrate (as calculated for N0 7.3
magnesium orthoborate (as calculated for boron): 4.3 The corrosion resistance time of the zinc surface, as
determined by the salt-fog method, is 52 hours.
EXAMPLE 3 Following the conditions of Example 1 following passivating composition was prepared (in party by weight): chromium nitrate (as calculated for chromium): 10.0 chromium-potassium alum (as calculated for chromium): 10.0 sodium monochromate (as calculated for chromium):
0.1 zinc nitrate (as calculated for N0 15.0 ammonium tetraborate (as calculated for boron): 4.2
Corrosion of zinc surface was resisted as determined by the salt-fog method, for 43 hours.
EXAMPLE 4 Following the conditions of Example 1. the following passivating composition was prepared (in parts by weight): chromium-potassium alum (as calculated for chromium): 5.0 potassium mono'chromate (as calculated for chromium): 2.0 cadmium nitrate (as calculated for N0 10.0 boric acid (as calculated for boron): 6.0
Corrosion of the zinc surface was resisted as determined by the salt-fog method, for 48 hours.
EXAMPLE 5 Following the conditions of Example 1. the following passivating composition was prepared (in parts by weight): chromium-potassium alum (as calculated for chromium): 8.0 sodiumbichromate (as calculated for chromium): 1.0 beryllium nitrate (as calculated for N0 25.0 sodium tetraborate (as calculated for boron): 1.8
Corrosion of the zinc surface was resisted, as determined by the salt-fog method, for 54 hours.
EXAMPLE 6 Following the conditions of Example 1, the following passivating composition was prepared (in parts by weight): chromium sulphate (as calculated for chromium): 10.5 lithium chromate (as calculated for chromium): 0.5 ammonium bichromate (as calculated for chromium):
0.7 ammonium nitrate (as calculated for N0 15.5 lithium tetraborate (as calculated for boron): 3.4
Corrosion of zinc surface was resisted. as determined by the salt-fog method, for 48 hours.
What we claim is:
l. A composition for passivating zinc comprising a mixture of the following components, in parts by weight of from 5.0 to 20.0 of trivalent chromium compounds, as calculated for the chromium; from 0.1-2.0 hexavalent chromium, as calculated for the chromium; from 10.0 to 25.0 of inorganic salts of nitric acid, as
calculated for the N0 radical; and from [.8 to 6.0 of boron-containing compounds, as calculated for the boron.
2. The composition for passivating zinc as claimed in claim 1 wherein the mixture comprises a mixture. in parts by weight, of from 8.0 to 13.0 of trivalent chromium compounds, as calculated for the chromium; from 0.7 1.1 of hexavalent chromium, as calculated for the chromium; from 13.0 to 16.0 of of inorganic salts of nitric acid, as calculated for N0 and from 2.5 to 4.5 of boron containing compounds, as calculated for the boron.
3. The composition for passivating zinc wherein the mixture consists essentially of the components as claimed in claim 1, and wherein the salts of nitric acid are selected from the group consisting of nitrates of ammonium, of beryllium, of potassium, of cadmium, of lithium, of magnesium, of sodium, of zinc, and of mixtures of said salts.
4. The composition as claimed in claim 3, wherein the boron component is an inorganic boron compound.
5. The composition as claimed in claim 4, wherein the boron component is selected from the group consisting of orthoboric acid, magnesium orthoborate, polyborates of ammonium, beryllium, potassium, lithium, magnesium, sodium, and mixtures thereof.
6. The composition as claimed in claim 1, wherein the trivalent chromium component is selected from the group consisting of chromic sulfates, chromic nitrates, and mixtures thereof.
7. The composition as claimed in claim 1, wherein the hexavalent chromium component is selected from the group consisting of chromium trioxide; the chromates and bichromates of ammonium, beryllium, potassium, cadmium, sodium, magnesium, lithium, and
zinc; and mixtures thereof.
Claims (7)
1. A COMPOUND FOR PASSIVATING ZINC COMPRISING A MIXTURE OF THE FOLLOWING COMPONENTS, IN PARTS BY WEIGHT OF FROM 5.0 TO 20.0 OF TRIVALENT CHROMIUM COMPOUNDS, AS CALCULATED FOR THE CHROMIUM; FROM 0.1-2.0 HEXAVALENT CHROMIUM, AS CALCULATED FOR THE CHROMIUM; FROM 10.0 TO 25.0 OF INORGANIC SALTS OF NITRIC ACID, AS CALCULATED FOR THE NO3- RADICAL; AND FROM 1.8 TO 6.0 OF BORON-CONTAINING COMPOUNDS, AS CALCULATED FOR THE BORON.
2. The composition for passivating zinc as claimed in claim 1 wherein the mixture comprises a mixture, in parts by weight, of from 8.0 to 13.0 of trivalent chromium compounds, as calculated for the chromium; from 0.7 - 1.1 of hexavalent chromium, as calculated for the chromium; from 13.0 to 16.0 of of inorganic salts of nitric acid, as calculated for NO3 : and from 2.5 to 4.5 of boron containing compounds, as calculated for the boron.
3. The composition for passivating zinc wherein the mixture consists essentially of the components as claimed in claim 1, and wherein the salts of nitric acid are selected from the group consisting of nitrates of ammonium, of beryllium, of potassium, of cadmium, of lithium, of magnesium, of sodium, of zinc, and of mixtures of said salts.
4. The composition as claimed in claim 3, wherein the boron component is an inorganic boron compound.
5. The composition as claimed in claim 4, wherein the boron component is selected from the group consisting of orthoboric acid, magnesium orthoborate, polyborates of ammonium, beryllium, potassium, lithium, magnesium, sodium, and mixtures thereof.
6. The composition as claimed in claim 1, wherein the trivalent chromium component is selected from the group consisting of chromic sulfates, chromic nitrates, and mixtures thereof.
7. The composition as claimed in claim 1, wherein the hexavalent chromium component is selected from the group consisting of chromium trioxide; the chromates and bichromates of ammonium, beryllium, potassium, cadmium, sodium, magnesium, lithium, and zinc; and mixtures thereof.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| SU7101702264A SU427614A1 (en) | 1971-10-05 | 1971-10-05 | Composition for zing passivation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US3880772A true US3880772A (en) | 1975-04-29 |
Family
ID=20489398
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US278867A Expired - Lifetime US3880772A (en) | 1971-10-05 | 1972-08-08 | Composition for ring passivation |
Country Status (10)
| Country | Link |
|---|---|
| US (1) | US3880772A (en) |
| CS (1) | CS171853B1 (en) |
| DD (1) | DD99182A1 (en) |
| DE (1) | DE2244489B2 (en) |
| FR (1) | FR2156579B1 (en) |
| GB (1) | GB1358216A (en) |
| HU (1) | HU164916B (en) |
| IT (1) | IT965190B (en) |
| PL (1) | PL84468B1 (en) |
| SU (1) | SU427614A1 (en) |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3213384A1 (en) * | 1981-04-16 | 1982-12-09 | Hooker Chemicals & Plastics Corp., 48089 Warren, Mich. | AQUEOUS ACID SOLUTION AND METHOD FOR THE TREATMENT OF RECEIVABLE METAL SUBSTRATES FOR THE AWARD OF A PASSIVATION FILM |
| US4756805A (en) * | 1985-11-01 | 1988-07-12 | Nihon Parkerizing Co., Ltd. | Treatment of galvanized steel |
Families Citing this family (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3423990A1 (en) * | 1983-07-19 | 1985-01-31 | Omi International Corp., Warren, Mich. | PEROXIDE-FREE CHROME (III) PASSIVATION SOLUTION AND METHOD FOR PASSIVATING SUBSTRATES WITH THIS SOLUTION |
| ES2046921B1 (en) * | 1991-05-13 | 1994-09-01 | Enthone Omi Inc | SEALING PROCEDURE FOR CHROMATE CONVERSION COATINGS ON ZINC ELECTROPOSED. |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3553034A (en) * | 1967-04-20 | 1971-01-05 | Lysaght Australia Ltd | Composition and process for inhibiting corrosion of zinc surfaces |
| US3582368A (en) * | 1968-12-30 | 1971-06-01 | Borden Inc | Corrosion-inhibiting composition |
| US3620777A (en) * | 1968-07-24 | 1971-11-16 | Hooker Chemical Corp | Chromate chemical coating solution for zinc alloy |
| US3706603A (en) * | 1967-06-14 | 1972-12-19 | Albright & Wilson | Metal coatings comprising hexavalent chromium,trivalent chromium,silica or a silicate and an alkali metal cation |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3121032A (en) * | 1960-09-27 | 1964-02-11 | M & T Chemicals Inc | Process for applying a protective transparent coating to zinc and cadmium and composition therefor |
| US3404046A (en) * | 1964-09-25 | 1968-10-01 | Hooker Chemical Corp | Chromating of zinc and aluminum and composition therefor |
-
1971
- 1971-10-05 SU SU7101702264A patent/SU427614A1/en active
-
1972
- 1972-08-08 US US278867A patent/US3880772A/en not_active Expired - Lifetime
- 1972-08-16 GB GB3818472A patent/GB1358216A/en not_active Expired
- 1972-09-02 IT IT52516/72A patent/IT965190B/en active
- 1972-09-05 FR FR7231458A patent/FR2156579B1/fr not_active Expired
- 1972-09-06 DD DD165484A patent/DD99182A1/xx unknown
- 1972-09-11 DE DE2244489A patent/DE2244489B2/en not_active Withdrawn
- 1972-09-15 CS CS6328A patent/CS171853B1/cs unknown
- 1972-10-03 HU HUII117A patent/HU164916B/hu unknown
- 1972-10-03 PL PL1972158054A patent/PL84468B1/pl unknown
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3553034A (en) * | 1967-04-20 | 1971-01-05 | Lysaght Australia Ltd | Composition and process for inhibiting corrosion of zinc surfaces |
| US3706603A (en) * | 1967-06-14 | 1972-12-19 | Albright & Wilson | Metal coatings comprising hexavalent chromium,trivalent chromium,silica or a silicate and an alkali metal cation |
| US3620777A (en) * | 1968-07-24 | 1971-11-16 | Hooker Chemical Corp | Chromate chemical coating solution for zinc alloy |
| US3582368A (en) * | 1968-12-30 | 1971-06-01 | Borden Inc | Corrosion-inhibiting composition |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3213384A1 (en) * | 1981-04-16 | 1982-12-09 | Hooker Chemicals & Plastics Corp., 48089 Warren, Mich. | AQUEOUS ACID SOLUTION AND METHOD FOR THE TREATMENT OF RECEIVABLE METAL SUBSTRATES FOR THE AWARD OF A PASSIVATION FILM |
| US4756805A (en) * | 1985-11-01 | 1988-07-12 | Nihon Parkerizing Co., Ltd. | Treatment of galvanized steel |
Also Published As
| Publication number | Publication date |
|---|---|
| DE2244489B2 (en) | 1979-11-15 |
| GB1358216A (en) | 1974-07-03 |
| DE2244489A1 (en) | 1973-04-12 |
| DD99182A1 (en) | 1973-07-20 |
| IT965190B (en) | 1974-01-31 |
| FR2156579A1 (en) | 1973-06-01 |
| PL84468B1 (en) | 1976-04-30 |
| FR2156579B1 (en) | 1976-08-13 |
| HU164916B (en) | 1974-05-28 |
| CS171853B1 (en) | 1976-11-29 |
| SU427614A1 (en) | 1977-11-05 |
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