EP2055810A2 - Procedure for anodising aluminium or aluminium alloys - Google Patents
Procedure for anodising aluminium or aluminium alloys Download PDFInfo
- Publication number
- EP2055810A2 EP2055810A2 EP08380076A EP08380076A EP2055810A2 EP 2055810 A2 EP2055810 A2 EP 2055810A2 EP 08380076 A EP08380076 A EP 08380076A EP 08380076 A EP08380076 A EP 08380076A EP 2055810 A2 EP2055810 A2 EP 2055810A2
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- EP
- European Patent Office
- Prior art keywords
- anodising
- procedure according
- aluminium
- concentration
- anodising procedure
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
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- 238000007743 anodising Methods 0.000 title claims abstract description 34
- 238000000034 method Methods 0.000 title claims abstract description 33
- 229910000838 Al alloy Inorganic materials 0.000 title claims abstract description 18
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 title claims abstract description 15
- 239000004411 aluminium Substances 0.000 title claims abstract description 15
- 229910052782 aluminium Inorganic materials 0.000 title claims abstract description 15
- 239000001117 sulphuric acid Substances 0.000 claims abstract description 21
- 235000011149 sulphuric acid Nutrition 0.000 claims abstract description 14
- 239000007864 aqueous solution Substances 0.000 claims abstract description 12
- FEWJPZIEWOKRBE-UHFFFAOYSA-N Tartaric acid Natural products [H+].[H+].[O-]C(=O)C(O)C(O)C([O-])=O FEWJPZIEWOKRBE-UHFFFAOYSA-N 0.000 claims abstract description 11
- 229910017053 inorganic salt Inorganic materials 0.000 claims abstract description 9
- 239000000243 solution Substances 0.000 claims abstract description 9
- 229910052723 transition metal Inorganic materials 0.000 claims abstract description 8
- 150000003624 transition metals Chemical class 0.000 claims abstract description 8
- 229910052768 actinide Inorganic materials 0.000 claims abstract description 4
- 150000001255 actinides Chemical class 0.000 claims abstract description 4
- 229910052747 lanthanoid Inorganic materials 0.000 claims abstract description 4
- 150000002602 lanthanoids Chemical class 0.000 claims abstract description 4
- 235000002906 tartaric acid Nutrition 0.000 claims abstract description 3
- 239000011975 tartaric acid Substances 0.000 claims abstract description 3
- QAOWNCQODCNURD-UHFFFAOYSA-N Sulfuric acid Chemical compound OS(O)(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-N 0.000 claims description 12
- 239000003792 electrolyte Substances 0.000 claims description 11
- FEWJPZIEWOKRBE-JCYAYHJZSA-N Dextrotartaric acid Chemical compound OC(=O)[C@H](O)[C@@H](O)C(O)=O FEWJPZIEWOKRBE-JCYAYHJZSA-N 0.000 claims description 9
- 235000011002 L(+)-tartaric acid Nutrition 0.000 claims description 8
- 239000001358 L(+)-tartaric acid Substances 0.000 claims description 8
- FEWJPZIEWOKRBE-LWMBPPNESA-N L-(+)-Tartaric acid Natural products OC(=O)[C@@H](O)[C@H](O)C(O)=O FEWJPZIEWOKRBE-LWMBPPNESA-N 0.000 claims description 8
- 150000002751 molybdenum Chemical class 0.000 claims description 6
- 150000003839 salts Chemical class 0.000 claims description 6
- 239000010935 stainless steel Substances 0.000 claims description 6
- 229910001220 stainless steel Inorganic materials 0.000 claims description 6
- 230000002378 acidificating effect Effects 0.000 claims description 5
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical group [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 claims 1
- 229910000831 Steel Inorganic materials 0.000 claims 1
- 239000010959 steel Substances 0.000 claims 1
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical compound [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 abstract description 9
- KRVSOGSZCMJSLX-UHFFFAOYSA-L chromic acid Substances O[Cr](O)(=O)=O KRVSOGSZCMJSLX-UHFFFAOYSA-L 0.000 abstract description 8
- AWJWCTOOIBYHON-UHFFFAOYSA-N furo[3,4-b]pyrazine-5,7-dione Chemical compound C1=CN=C2C(=O)OC(=O)C2=N1 AWJWCTOOIBYHON-UHFFFAOYSA-N 0.000 abstract description 8
- 239000010410 layer Substances 0.000 description 7
- 239000002344 surface layer Substances 0.000 description 7
- 230000007797 corrosion Effects 0.000 description 6
- 238000005260 corrosion Methods 0.000 description 6
- 238000004140 cleaning Methods 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- 239000003929 acidic solution Substances 0.000 description 4
- 230000000052 comparative effect Effects 0.000 description 4
- AZDRQVAHHNSJOQ-UHFFFAOYSA-N alumane Chemical group [AlH3] AZDRQVAHHNSJOQ-UHFFFAOYSA-N 0.000 description 3
- 239000012153 distilled water Substances 0.000 description 3
- 239000003973 paint Substances 0.000 description 3
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 2
- 238000003556 assay Methods 0.000 description 2
- 238000007654 immersion Methods 0.000 description 2
- 229910052751 metal Inorganic materials 0.000 description 2
- 239000002184 metal Substances 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- QMXBEONRRWKBHZ-UHFFFAOYSA-N [Na][Mo] Chemical compound [Na][Mo] QMXBEONRRWKBHZ-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 1
- 239000004327 boric acid Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 231100001261 hazardous Toxicity 0.000 description 1
- 231100000086 high toxicity Toxicity 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- 231100000419 toxicity Toxicity 0.000 description 1
- 230000001988 toxicity Effects 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D11/00—Electrolytic coating by surface reaction, i.e. forming conversion layers
- C25D11/02—Anodisation
- C25D11/04—Anodisation of aluminium or alloys based thereon
- C25D11/06—Anodisation of aluminium or alloys based thereon characterised by the electrolytes used
Definitions
- This invention refers to a process for anodising aluminium or aluminium alloy parts, including pure or almost pure aluminium and all its combinations with other elements in any proportion.
- the acidic solutions used in anodising procedures are composed of sulphuric acid in high concentrations, or of chromic acid.
- the latter is the main component used in the aerospace industry.
- Sulphuric acid is not used in the aerospace industry due to the low adherence in the treated parts, while chromic acid has a high toxicity in live beings and is hazardous for the environment.
- the aqueous tartaric-sulphuric acid solution is an alternative method to anodise parts through an electrolytic process with low environmental impact. This method is described in patent number US 2002/0157961 A1 .
- Another alternative method is an aqueous solution of sulphuric acid and boric acid described in US patent 4894127 . These methods do not provide the aluminium or aluminium alloy parts with the same properties pertaining to corrosion as the chromic acid treatment.
- the procedure in this invention uses the aluminium or aluminium alloy parts, described as anodes in an electrolytic cell with an aqueous acidic electrolyte, in order to create a superficial layer of aluminium oxide on said parts.
- This superficial aluminium oxide improves the properties pertaining to resistance against corrosion and surface layer adherence of an aluminium or aluminium alloy part.
- This invention refers to an anodising procedure for aluminium or aluminium alloys in which the aluminium or aluminium alloy parts are submerged in an aqueous solution at a temperature between 0°C and 130°C, and where said solution includes:
- the inorganic salt of the transition metal may be present in a concentration between 5 ⁇ 10 -7 and 1.5 M, preferably in a concentration between 1 ⁇ 10 -6 and 1 M.
- said inorganic salt of the transition metal may be a salt of at least one metal selected between metals from the IIIB, IVB, VB, VIB, VIIB, VIIIB, IB. and IIB groups, a salt from a lanthanide or actinide element, combinations of the previous ones, and preferably a molybdenum salt.
- inorganic salt or salts behave as corrosion inhibitors by preventing the development of the different corrosion reactions (depending on the type of inorganic salt), therefore improving the behaviour of the parts pertaining to corrosion.
- the same aluminium or aluminium alloy parts to be anodised can be used as an anode.
- the electrolyte is an aqueous acidic electrolyte; preferably it is an aqueous solution of tartaric-sulphuric acid.
- the aqueous solution that acts as an electrolyte has a concentration of sulphuric acid between 0.1 and 1.5 M, preferably between 0.2 M and 0.9 M, and a concentration of L(+)-tartaric acid between 0.1 and 1.5 M, preferably between 0.2 and 0.8M.
- said solution has a concentration of sulphuric acid between 0.2 M and 0.9 M, L(+)-tartaric acid with a concentration between 0.2 and 0.8M, and one or several inorganic salts composed of at least one or several transition metals in a concentration between 1 ⁇ 10 -6 and 1 M.
- the temperature of the aqueous solution is kept between 0°C and 140°C, preferably between 0°C and 130°C, even more preferably between 5°C and 80°C, and most preferably between 30 and 40°C.
- the electrolytic cell is subject to a potential difference 0.5V and 130V, preferably between 1 V and 120 V, even more preferably between 2 V and 100 V, and most preferably between 10 and 30 V according to the procedure.
- the duration of the anodising procedure is between 1 and 130 minutes, preferably between 5 and 120 minutes, and more preferably between 5 and 40 minutes.
- This procedure has a duration cycle of about 40% less time as regards traditional chromic acid anodising.
- a 2000 series aluminium alloy part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment: degreasing by immersion for approximately 10 minutes, rinse in distilled water for approximately 5 minutes, surface layer removal for approximately 10 minutes, and rinse in distilled water for 5 minutes.
- the part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is composed of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area.
- the electrolyte is an aqueous acidic solution made of 0.40 M sulphuric acid, 0.53 M L (+)-tartaric acid, and 0.25M sodium molybdenum.
- the cell's temperature is at 37°C ⁇ 1°C.
- the potential difference increases from 0 to 14 V at a rate of 2.8 V ⁇ min-1, and it stays at 14 V for 20 minutes, creating an oxide layer of approximately 2 ⁇ m.
- the part is rinsed in anodised water for approximately 5 minutes, and it is sealed in anodised water at boiling point for approximately 40 minutes. Then it is dried with hot air.
- a 2000 series plaqued aluminium part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- the part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area.
- the electrolyte and the anodising conditions are the same as those described in Example 1, obtaining an oxide layer of approximately 2 ⁇ m.
- the anodised part is rinsed and sealed in the same manner as that described in example 1.
- a 2000 series aluminium alloy part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- the part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area.
- the electrolyte and the anodising conditions are the same as those described in Example 1, obtaining an oxide layer of approximately 3 ⁇ m.
- the anodised part is rinsed and sealed in the same manner as that described in example 1.
- a 2000 series plaqued aluminium part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- the part is completely submerged in an electrolytic cell, where the part functions as an anode;
- the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area.
- the electrolyte is an aqueous acidic solution made of 0.40 M sulphuric acid and 0.53 M L (+)-tartaric acid.
- the cell's temperature is maintained at 37°C ⁇ 1°C.
- the potential difference increases from 0 to 14 V at a rate of 2.8 V ⁇ min-1, and it is maintained at 14 V for 20 minutes, creating an oxide layer of approximately 3 ⁇ m.
- the anodised part is rinsed and sealed as in Example 1.
- a 2000 series plaqued aluminium part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- the part is completely submerged in an electrolytic cell, where the part functions as an anode;
- the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area.
- the electrolyte is an aqueous acidic solution with chromic acid. The cell's temperature is maintained between 35°C and 40°C.
- the potential difference increases from 0 to 40 V at a rate of 5 V ⁇ min-1, and it stays at 14 V for 45 minutes, creating an oxide layer of approximately 3 ⁇ m.
- the anodised part is rinsed and sealed as in Example 1.
- Table 1 Comparison of properties in the parts treated according to the previous examples Part Thickness ( ⁇ m) (1) 96 hours of exposure (1) 336 hours of exposure (2) Adherence of dried paint (Gt) (2) Adherence of damp paint /Gt) Ex. 1 2 Pass Pass 0 0 Ex. 2 Pass Pass 0 0 Ex. 3 Pass Fail 0 0 Ex. 4 3 Pass Fail 0 0 Ex. 5 3 Pass Pass 0 0 (1) Assay in saline fog chamber according to standard ASTM B 117. (2) Assay of paint adherence according to standard ISO 2409 (before and after 14 days of immersion in distilled water).
- the parts treated according to the invention exceed 336 hours in saline fog according to the requirement established in section 3.7.1.2 of the military standard MIL-A-8625-F for IC type anodic layers.
- the comparison of the obtained results for the tests done on the example parts according to the invention and the comparative example conclude that the oxides created by the invention have better properties pertaining to corrosion than the oxides created in aqueous acidic mediums without inorganic salts. These properties are equal to or better than the ones obtained through anodising in chromic acid.
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- Chemical & Material Sciences (AREA)
- Engineering & Computer Science (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Electrochemistry (AREA)
- Materials Engineering (AREA)
- Metallurgy (AREA)
- Organic Chemistry (AREA)
- Chemical Treatment Of Metals (AREA)
- Water Treatment By Electricity Or Magnetism (AREA)
- Printing Plates And Materials Therefor (AREA)
- Cleaning And De-Greasing Of Metallic Materials By Chemical Methods (AREA)
Abstract
- sulphuric acid,
- tartaric acid, and
- at least one inorganic salt of an element selected between at least one transition metal, a lanthanide element, an actinide, and combinations of them,
and applying a controlled potential difference, obtaining layers of aluminium oxide with properties as good as or even better than those obtained through anodising in traditional chromic acid solutions.
Description
- This invention refers to a process for anodising aluminium or aluminium alloy parts, including pure or almost pure aluminium and all its combinations with other elements in any proportion.
- Traditionally, the acidic solutions used in anodising procedures are composed of sulphuric acid in high concentrations, or of chromic acid. The latter is the main component used in the aerospace industry. Sulphuric acid is not used in the aerospace industry due to the low adherence in the treated parts, while chromic acid has a high toxicity in live beings and is hazardous for the environment. The aqueous tartaric-sulphuric acid solution is an alternative method to anodise parts through an electrolytic process with low environmental impact. This method is described in patent number
US 2002/0157961 A1 . Another alternative method is an aqueous solution of sulphuric acid and boric acid described inUS patent 4894127 . These methods do not provide the aluminium or aluminium alloy parts with the same properties pertaining to corrosion as the chromic acid treatment. - The procedure in this invention uses the aluminium or aluminium alloy parts, described as anodes in an electrolytic cell with an aqueous acidic electrolyte, in order to create a superficial layer of aluminium oxide on said parts. This superficial aluminium oxide improves the properties pertaining to resistance against corrosion and surface layer adherence of an aluminium or aluminium alloy part.
- This invention refers to an anodising procedure for aluminium or aluminium alloys in which the aluminium or aluminium alloy parts are submerged in an aqueous solution at a temperature between 0°C and 130°C, and where said solution includes:
- sulphuric acid,
- tartaric acid, and
- at least one inorganic salt of an element selected between at least one transition metal, one lanthanide element, one actinide, and combinations of them, and apply a controlled potential difference.
- The inorganic salt of the transition metal may be present in a concentration between 5·10-7 and 1.5 M, preferably in a concentration between 1·10-6 and 1 M.
- In the invention's procedure, said inorganic salt of the transition metal may be a salt of at least one metal selected between metals from the IIIB, IVB, VB, VIB, VIIB, VIIIB, IB. and IIB groups, a salt from a lanthanide or actinide element, combinations of the previous ones, and preferably a molybdenum salt.
- The previously mentioned inorganic salt or salts behave as corrosion inhibitors by preventing the development of the different corrosion reactions (depending on the type of inorganic salt), therefore improving the behaviour of the parts pertaining to corrosion.
- The same aluminium or aluminium alloy parts to be anodised can be used as an anode.
- According to particular embodiments, the electrolyte is an aqueous acidic electrolyte; preferably it is an aqueous solution of tartaric-sulphuric acid.
- According to a preferred embodiment, the aqueous solution that acts as an electrolyte has a concentration of sulphuric acid between 0.1 and 1.5 M, preferably between 0.2 M and 0.9 M, and a concentration of L(+)-tartaric acid between 0.1 and 1.5 M, preferably between 0.2 and 0.8M.
- According to the most preferable embodiment, said solution has a concentration of sulphuric acid between 0.2 M and 0.9 M, L(+)-tartaric acid with a concentration between 0.2 and 0.8M, and one or several inorganic salts composed of at least one or several transition metals in a concentration between 1·10-6 and 1 M.
- During the anodising process, the temperature of the aqueous solution is kept between 0°C and 140°C, preferably between 0°C and 130°C, even more preferably between 5°C and 80°C, and most preferably between 30 and 40°C.
- The electrolytic cell is subject to a potential difference 0.5V and 130V, preferably between 1 V and 120 V, even more preferably between 2 V and 100 V, and most preferably between 10 and 30 V according to the procedure.
- The duration of the anodising procedure is between 1 and 130 minutes, preferably between 5 and 120 minutes, and more preferably between 5 and 40 minutes.
- This procedure has a duration cycle of about 40% less time as regards traditional chromic acid anodising.
- The toxicity and hazardousness to the environment of the residues created by this invention is greatly reduced when compared to those created by the traditional anodising procedures.
- A 2000 series aluminium alloy part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment: degreasing by immersion for approximately 10 minutes, rinse in distilled water for approximately 5 minutes, surface layer removal for approximately 10 minutes, and rinse in distilled water for 5 minutes.
- Then the part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is composed of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area. The electrolyte is an aqueous acidic solution made of 0.40 M sulphuric acid, 0.53 M L (+)-tartaric acid, and 0.25M sodium molybdenum. The cell's temperature is at 37°C ± 1°C. The potential difference increases from 0 to 14 V at a rate of 2.8 V·min-1, and it stays at 14 V for 20 minutes, creating an oxide layer of approximately 2 µm.
- The part is rinsed in anodised water for approximately 5 minutes, and it is sealed in anodised water at boiling point for approximately 40 minutes. Then it is dried with hot air.
- A 2000 series plaqued aluminium part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- The part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area. The electrolyte and the anodising conditions are the same as those described in Example 1, obtaining an oxide layer of approximately 2 µm.
- The anodised part is rinsed and sealed in the same manner as that described in example 1.
- A 2000 series aluminium alloy part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- The part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area. The electrolyte and the anodising conditions are the same as those described in Example 1, obtaining an oxide layer of approximately 3 µm.
- The anodised part is rinsed and sealed in the same manner as that described in example 1.
- A 2000 series plaqued aluminium part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- Then the part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area. The electrolyte is an aqueous acidic solution made of 0.40 M sulphuric acid and 0.53 M L (+)-tartaric acid. The cell's temperature is maintained at 37°C ± 1°C.
- The potential difference increases from 0 to 14 V at a rate of 2.8 V·min-1, and it is maintained at 14 V for 20 minutes, creating an oxide layer of approximately 3 µm.
- The anodised part is rinsed and sealed as in Example 1.
- A 2000 series plaqued aluminium part, 150x100x2 mm, is subjected to a conventional cleaning and surface layer removal treatment, as described in Example 1.
- Then the part is completely submerged in an electrolytic cell, where the part functions as an anode; the cathode is made of AISI 321 stainless steel, and it has a geometric area equal to or larger than the anode's geometric area. The electrolyte is an aqueous acidic solution with chromic acid. The cell's temperature is maintained between 35°C and 40°C.
- The potential difference increases from 0 to 40 V at a rate of 5 V·min-1, and it stays at 14 V for 45 minutes, creating an oxide layer of approximately 3 µm.
- The anodised part is rinsed and sealed as in Example 1.
Table 1. Comparison of properties in the parts treated according to the previous examples Part Thickness (µm) (1)96 hours of exposure (1)336 hours of exposure (2)Adherence of dried paint (Gt) (2)Adherence of damp paint /Gt) Ex. 1 2 Pass Pass 0 0 Ex. 2 Pass Pass 0 0 Ex. 3 Pass Fail 0 0 Ex. 4 3 Pass Fail 0 0 Ex. 5 3 Pass Pass 0 0 (1) Assay in saline fog chamber according to standard ASTM B 117.
(2) Assay of paint adherence according to standard ISO 2409 (before and after 14 days of immersion in distilled water). - The parts treated according to the invention exceed 336 hours in saline fog according to the requirement established in section 3.7.1.2 of the military standard MIL-A-8625-F for IC type anodic layers.
- The comparison of the obtained results for the tests done on the example parts according to the invention and the comparative example conclude that the oxides created by the invention have better properties pertaining to corrosion than the oxides created in aqueous acidic mediums without inorganic salts. These properties are equal to or better than the ones obtained through anodising in chromic acid.
Claims (15)
- An anodising procedure for aluminium or aluminium alloys characterised in that it comprises in submerges an aluminium or aluminium alloy part in an aqueous solution, said solution comprising:- sulphuric acid,- tartaric acid, and- at least one inorganic salt of an element selected between at least one transition metal, one lanthanide element, one actinide, and a combination of them, and apply a controlled potential difference.
- An anodising procedure according to claim 1, characterised in that said aqueous solution also includes one inorganic salt of a transition metal with a concentration between 1·10-6 and 1 M.
- An anodising procedure according to claim 1, characterised in that said inorganic salt is a molybdenum salt.
- An anodising procedure according to claim 1, characterised in that as the anode is the same aluminium or aluminium alloy parts to be anodised.
- An anodising procedure according to claim 1, characterised in that one aqueous acidic electrolyte is used.
- An anodising procedure according to claim 1, characterised in that said aqueous acidic electrolyte is an aqueous, tartaric-sulphuric solution.
- An anodising procedure according to claim 6, characterised in that said solution has a concentration of sulphuric acid between 0.2 M and 0.9 M, L(+)-tartaric acid with a concentration between 0.2 and 0.8M.
- An anodising procedure according to claim 6, characterised in that said solution has a concentration of sulphuric acid between 0.2 M and 0.9 M, L(+)-tartaric acid with a concentration between 0.2 and 0.8M, and one or several inorganic salts with at least one or several transition metals with a concentration between 1·10-6 and 1 M.
- An anodising procedure according to claim 1, characterised in that the temperature of the aqueous solution is maintained during the anodising process between 0°C and 130°C.
- An anodising procedure according to claim 1, characterised in that a difference of electrical potencial between 1V and 120V is applied to the electrolytic cell.
- An anodising procedure according to claim 1, characterised in that it takes between 5 and 120 minutes of time.
- An anodising procedure according to claim 1, characterised in that a steel plate is used for the cathode.
- An anodising procedure according to claim 1, characterised in that an aqueous solution of tartaric-sulphuric acid and a molybdenum salt are used.
- An anodising procedure according to claim 1, characterised in that the aqueous solution is made up of sulphuric acid whose concentration is between 0.20 and 0.50 M, L (+)-tartaric acid with a concentration between 0.4 and 0.55 M, and molybdenum salt whose concentration is between 0.20 M and 0.30 M.
- An anodising procedure according to claim 1, characterised in that it comprises:- a cathode made of AISI 321 stainless steel whose area is equal to or larger than the area of the anode,- an aqueous solution made up of 0.40 M sulphuric acid, 0.53 M L (+)-tartaric acid, and 0.25 M molybdenum salt, and- an electrolytic cell's temperature maintained at 37°C ± 1°C., comprising a potential difference of 0 to 14 V applied at rate of 2.8 V·min-1 and maintained during 20 minutes.
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
ES200702842A ES2324850B1 (en) | 2007-10-29 | 2007-10-29 | PROCEDURE FOR ANODIZED ALUMINUM OR ALUMINUM ALLOYS. |
Publications (2)
Publication Number | Publication Date |
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EP2055810A2 true EP2055810A2 (en) | 2009-05-06 |
EP2055810A3 EP2055810A3 (en) | 2013-01-23 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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EP08380076A Withdrawn EP2055810A3 (en) | 2007-10-29 | 2008-03-07 | Procedure for anodising aluminium or aluminium alloys |
Country Status (7)
Country | Link |
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US (1) | US20090107848A1 (en) |
EP (1) | EP2055810A3 (en) |
CN (1) | CN101423965A (en) |
BR (1) | BRPI0800622A2 (en) |
CA (1) | CA2624579A1 (en) |
EA (1) | EA015400B1 (en) |
ES (1) | ES2324850B1 (en) |
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EP3445896B1 (en) | 2016-04-18 | 2023-10-18 | Fokker Aerostructures B.V. | Method of anodizing an article of aluminium or alloy thereof |
RU2694430C1 (en) * | 2018-08-31 | 2019-07-15 | Российская Федерация в лице Общество с ограниченной ответственностью "РУСОКСИД" (ООО "РУСОКСИД") | Method of producing dielectric layer on aluminium substrate surface |
WO2020160690A1 (en) * | 2019-02-08 | 2020-08-13 | Hewlett-Packard Development Company, L.P. | Surface treatments |
CN110306940B (en) | 2019-08-05 | 2020-04-28 | 湖南科技大学 | Rotary supporting device of submarine drilling rig in large-capacity compact drilling pipe warehouse in horizontal lying state |
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GB459263A (en) * | 1935-04-25 | 1937-01-05 | Schering Kahlbaum Ag | Process for the anodic coating of aluminium and aluminium alloys and electrolytes therefor |
US20020157961A1 (en) * | 2001-02-20 | 2002-10-31 | Alenia Aeronautica S.P.A. | Anodizing process, with low environmental impact, for a woodpiece of aluminum or aluminum alloys |
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FR1331558A (en) * | 1962-05-25 | 1963-07-05 | Carnaud & Forges | Improvements to the anodic oxidation of aluminum processes |
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US5205922A (en) * | 1990-11-20 | 1993-04-27 | The United States Of America As Represented By The Secretary Of The Navy | Formation of pitting resistant anodized films on aluminum |
DK187391D0 (en) * | 1991-11-15 | 1991-11-15 | Inst Produktudvikling | PROCEDURE FOR THE TREATMENT OF ZINC COATED MATERIALS AND TREATMENT SOLUTION FOR USE BY THE PROCEDURE |
GB9825043D0 (en) * | 1998-11-16 | 1999-01-13 | Agfa Gevaert Ltd | Production of support for lithographic printing plate |
DE10361888B3 (en) * | 2003-12-23 | 2005-09-22 | Airbus Deutschland Gmbh | Anodizing process for aluminum materials |
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2007
- 2007-10-29 ES ES200702842A patent/ES2324850B1/en not_active Expired - Fee Related
-
2008
- 2008-03-07 US US12/073,632 patent/US20090107848A1/en not_active Abandoned
- 2008-03-07 CA CA002624579A patent/CA2624579A1/en not_active Abandoned
- 2008-03-07 EP EP08380076A patent/EP2055810A3/en not_active Withdrawn
- 2008-03-13 EA EA200800582A patent/EA015400B1/en not_active IP Right Cessation
- 2008-03-14 BR BRPI0800622-9A patent/BRPI0800622A2/en not_active IP Right Cessation
- 2008-03-17 CN CNA2008100963066A patent/CN101423965A/en active Pending
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GB459263A (en) * | 1935-04-25 | 1937-01-05 | Schering Kahlbaum Ag | Process for the anodic coating of aluminium and aluminium alloys and electrolytes therefor |
US20020157961A1 (en) * | 2001-02-20 | 2002-10-31 | Alenia Aeronautica S.P.A. | Anodizing process, with low environmental impact, for a woodpiece of aluminum or aluminum alloys |
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Cited By (1)
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---|---|---|---|---|
EP4269662A1 (en) | 2022-04-29 | 2023-11-01 | Airbus Operations GmbH | Methods for anodizing a part surface and subsequently coating the anodized part surface for corrosion protection purposes |
Also Published As
Publication number | Publication date |
---|---|
BRPI0800622A2 (en) | 2009-06-30 |
EA200800582A1 (en) | 2009-06-30 |
ES2324850B1 (en) | 2010-06-07 |
EP2055810A3 (en) | 2013-01-23 |
ES2324850A1 (en) | 2009-08-17 |
US20090107848A1 (en) | 2009-04-30 |
EA015400B1 (en) | 2011-08-30 |
CN101423965A (en) | 2009-05-06 |
CA2624579A1 (en) | 2009-04-29 |
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