EP1445352A1 - Ein Verfahren zur Herstellung einer Passivierungsschicht auf einem Gegenstand mit wenigstens einer Zinn-Oberfläche - Google Patents

Ein Verfahren zur Herstellung einer Passivierungsschicht auf einem Gegenstand mit wenigstens einer Zinn-Oberfläche Download PDF

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Publication number
EP1445352A1
EP1445352A1 EP04001036A EP04001036A EP1445352A1 EP 1445352 A1 EP1445352 A1 EP 1445352A1 EP 04001036 A EP04001036 A EP 04001036A EP 04001036 A EP04001036 A EP 04001036A EP 1445352 A1 EP1445352 A1 EP 1445352A1
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Prior art keywords
tin
sodium
concentration
article
electrolytic solution
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EP04001036A
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English (en)
French (fr)
Inventor
Alberto Billi
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KME Italy SpA
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Europa Metalli SpA
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    • 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
    • C25D11/34—Anodisation of metals or alloys not provided for in groups C25D11/04 - C25D11/32

Definitions

  • the present invention relates to a method for forming a passivation layer on an article having at least one tin-plated surface.
  • Said methods comprise a step in which the metal surfaces are treated so as to form, for instance in an aqueous solution, a passivated layer, for example a layer of oxide, which is not very reactive and will have a smaller degree of dissolution.
  • a purpose of the present invention is, hence, to provide a method for obtaining a passivation layer on an article having at least one tin-plated surface which will enable electrochemical oxidation to be carried out in bland conditions of pH, and current density and in short times and thus obtain articles that will have improved characteristics as compared to the known art and, in particular that will be provided with a passivation layer, which is continuous, thin, and highly adherent to the substrate, presents excellent mechanical characteristics, and will also possibly have different colours so as to enable application on as many materials as possible.
  • a further purpose of the present invention is to provide a method for forming a passivation layer that will be universally usable for different articles on which it is necessary to form a passivation layer and which may even be very different from one another.
  • a method for forming a passivation layer on an article having at least one tin-plated surface characterized in that it comprises the step of subjecting said tin-plated surface to electrochemical oxidation for forming on said tin-plated surface a layer of tin dioxide having a crystalline structure of the type of natural cassiterite.
  • a tin-plated article characterized in that it is coated with a layer of tin dioxide having a crystalline structure of the type of natural cassiterite.
  • a method for forming a passivation layer on an article having at least one tin-plated surface comprising the step of subjecting the tin-plated surface to electrochemical oxidation in order to form, on the tin-plated surface itself, a layer of tin dioxide SnO 2 having a crystalline structure of the type of natural cassiterite.
  • solutions preferred are electrolytic solutions comprising at least one compound chosen in the group constituted by salts of gluconic acid, salts of citric acid, and salts of boric acid.
  • Electrochemical oxidation takes place preferably at a pH of between 6 and 9, hence in almost neutral conditions or just slightly alkaline conditions.
  • the current density is preferably between 0.1 A/dm 2 and 10 A/dm 2 , and the potential difference of between 2.5 V and 31 V.
  • the temperature is preferably between 30°C and 80°C, and the oxidation time is between 0.5 min and 4 min.
  • stainless steel or titanium coated with platinum may preferably be used.
  • electrolytic solutions comprising as complexing agents a mixture of sodium tetraborate, boric acid and sodium gluconate.
  • a temperature of between 20°C and 80°C is to be preferred, and a pH of between 7 and 8.
  • a current density of between 2 A/dm 2 and 10 A/dm 2 is preferred, with a potential difference of between 8 V and 31 V.
  • the preferred concentrations are the following:
  • an electrolytic solution comprising as complexing agents a mixture of sodium carbonate and sodium gluconate may preferably be used.
  • a temperature of between 30°C and 50°C is to be preferred and a pH of between 11 and 11.5.
  • the time for anodization is preferably between 1 min and 4 min.
  • a current density of between 0.31 A/dm 2 and 10 A/dm 2 is preferred, with a potential difference of between 3.6 V and 25 V.
  • an electrolytic solution comprising, as complexing agents, a mixture of sodium bicarbonate and sodium gluconate may preferably be used.
  • a temperature of between 30°C and 50°C is preferred and a pH of between 7.0 and 11.5.
  • the time for anodization is preferably between 1 and 4 min.
  • a current density of between 0.30 A/dm 2 and 10 A/dm 2 is preferred, with a potential difference of between 3.6 V and 25 V.
  • the preferred concentrations are the following:
  • an electrolytic solution comprising, as complexing agents, a mixture of sodium bicarbonate, sodium carbonate and sodium gluconate may preferably be used.
  • a temperature of between 30°C and 80°C is preferred, and a pH of between 9.0 and 9.5.
  • the time for anodization is preferably between 1 min and 4 min.
  • a current density of between 3 A/dm 2 and 10 A/dm 2 is preferred, with a potential difference of between 8 V and 15 V.
  • the preferred concentrations are the following:
  • an electrolytic solution comprising, as complexing agents, a mixture of disodium hydrogen phosphate (Na 2 HPO 4 ) and sodium gluconate may preferably be used.
  • a temperature of between 36°C and 60°C is preferred, and a pH of between 9.10 and 10.
  • the time for anodization is preferably between 1 min and 4 min.
  • a current density of between 6 A/dm 2 and 10 A/dm 2 is preferred, with a potential difference of between 10 V and 17 V.
  • the preferred concentrations are the following:
  • an electrolytic solution comprising, as complexing agents, a mixture of sodium gluconate and potassium gluconate may preferably be used.
  • a temperature of between 30°C and 80°C is preferred, and a pH of between 7 and 8.
  • the time for anodization is preferably between 0.5 min and 2 min.
  • a current density of between 2 A/dm 2 and 10 A/dm 2 is preferred, with a potential difference of between 8 V and 15 V.
  • the preferred concentration of complexing agent is between 0.085 M and 0.120 M.
  • an electrolytic solution comprising, as complexing agents, a mixture of sodium citrate and sodium gluconate may preferably be used.
  • a temperature of between 32°C and 50°C is preferred, and a pH of between 9 and 9.5.
  • the time for anodization is preferably between 1 min and 4 min.
  • a current density of between 5 A/dm 2 and 10 A/dm 2 is preferred, with a potential difference of between 10.3 V and 16.8 V.
  • the preferred concentrations are the following:
  • a passivation layer is obtained by electrolytic oxidation or anodization, said layer consisting of tin dioxide SnO 2 having a crystallization state of a tetragonal type, hence similar to that of the natural mineral of tin, i.e., cassiterite.
  • tin dioxide formed using the electrolytic solutions described above can be characterized via diffractometric studies capable of detecting the presence of tin dioxide itself and the absence of tin monoxide or tin oxide SnO (where tin presents the oxidation state +2), as illustrated in Figures 1 and 2.
  • Figure 1 refers to an article made of tin-plated copper produced via electrochemical tin-plating
  • Figure 2 refers to an article made of tin-plated copper obtained via hot tin-plating. Both of said articles underwent electrochemical oxidation or anodization.
  • the analyses of the surfaces were carried out using, as exciting radiation, the Ka of magnesium (1253.6 eV) with a power of 180 W (12 kV x 15 mA) with energy steps of 90 eV, whilst in regions corresponding to the XPS and Auger transitions the step was 44 eV in order to improve resolution of the peak. Traces of sodium (see XPS peak Na 1 s) were detected.
  • the comparison of the binding energies obtained for the XPS peak Sn 3d 5/ 2 of tin with the data provided in the literature, for both of the oxidized forms SnO and SnO 2 , in some cases does not enable perfect differentiation of the two oxidized forms.
  • a further preferred application is to facades, windows and in the production of implements having tin-plated surfaces.
  • a further preferred application is in the steel industry for passivation of the internal surfaces made of tin-plated steel in the foodstuff-canning industry in order to prevent direct contact with the food, in so far as cassiterite or tin dioxide is considerably less soluble than tin monoxide also in these conditions.
  • a further particularly preferred application is in the field of superconductors, in particular in superconductor wires or cables made of niobium-titanium alloys or other alloys or ceramic compounds, englobed in a sheath made of copper or other metals, such as silver or aluminium, coated with tin or tin alloys, for example tin-silver (SnAg5) alloy.
  • tin or tin alloys for example tin-silver (SnAg5) alloy.
  • Cassiterite or tin dioxide which is an electrically insulating material, when it is electrochemically deposited in controlled conditions, enables a uniform, very adherent and continuous layer to be obtained, with a drastic reduction in energy losses due to mutual coupling of single and/or assembled superconductor wires.
  • a further preferred application is in water-distribution systems, for example for pipe connectors, valves, and a wide variety of tin-plated components, which can be treated for limiting dissolution of the underlying tin and of copper in drinking water or in other liquids.
  • Cassiterite or tin-dioxide coatings are able to reduce dissolution of lead considerably in the components used for distribution of drinking water, when they have previously been tin-plated.
  • each bath was tested as regards the coating obtained.
  • Each of the seven baths given in the following examples provides coating layers made of tin dioxide in the tetragonal crystalline form, of the cassiterite type, according to the present invention.
  • a solution was prepared with sodium tetraborate, boric acid and sodium gluconate, according to what is specified in Table 1.
  • Electrolytic aqueous solution Sodium tetraborate (Na 4 B 4 O 7 ⁇ 10H 2 O): 0.10 M + Boric acid (H 3 BO 3 ): 0.50 M + Sodium gluconate C 6 H 11 NaO 7 : 0.05 M Temperature 50°C ⁇ 5°C pH 7.60; buffered solution Current density 7.50 A/dm 2 Potential difference 15 - 18 V
  • Cathode Stainless steel AISI 316 Anode-cathode distance 30 - 60 mm Anodization time 1-4 min Stirring Not necessary
  • Pre-treatment Not necessary
  • a solution was prepared with sodium carbonate and sodium gluconate, according to what is specified in Table 2.
  • Electrolytic aqueous solution Sodium carbonate (Na 2 CO 3 ): 0.1 M + Sodium gluconate: 0.025 M Temperature 35°C ⁇ 2 °C pH 11.0 Current density 7.5 A/dm 2 Potential difference 15 V Cathode Stainless steel AISI 316 Anode-cathode distance 30 - 60 mm Anodization time 2 min Stirring Not necessary Pre-treatment Not necessary
  • a solution was prepared with sodium bicarbonate and sodium gluconate, according to what is specified in Table 3.
  • Electrolytic aqueous solution Sodium bicarbonate (NaHCO 3 ): 2,0 M + Sodium gluconate: 0.05 M Temperature 50°C ⁇ 2°C pH 7.87 Current density 10 A/dm 2 Potential difference 8.5 V
  • Anodization time 1 - 4 min Stirring Not necessary
  • a solution was prepared with sodium carbonate, sodium bicarbonate and sodium gluconate, according to what is specified in Table 4.
  • Electrolytic aqueous solution Sodium carbonate: 0.1 M + Sodium bicarbonate: 0.25 M + Sodium gluconate: 0.025 M
  • Density of current 7.5 A/dm 2 Potential difference 8.9 -10.9 V
  • Anodization time 1 - 4 min Stirring Not necessary
  • Pre-treatment Not necessary
  • a solution was prepared with disodium hydrogen phosphate and sodium gluconate according to what is specified in Table 5.
  • Electrolytic aqueous solution Disodium hydrogen phosphate (Na 2 HPO 4 ⁇ 12 H 2 O) 0.25 M + Sodium gluconate 0.025 M.
  • Cathode Stainless steel AISI 316 Anode-cathode distance 30 - 60 mm Anodization time 2 min Stirring Not necessary
  • Pre-treatment Not necessary
  • a solution was prepared with sodium gluconate and potassium gluconate according to what is specified in Table 6.
  • a solution was prepared with sodium gluconate and sodium citrate according to what is specified in Table 7.
  • Electrolytic solution Dehydrated sodium citrate (Na 3 C 6 H 11 O 7 ⁇ 2H 2 O):0.10M+ Sodium gluconate: 0.025 M Temperature 37°C ⁇ 2°C pH 9.10 Current density 8.5 A/dm 2 Potential difference 12 V Cathode Stainless steel AISI 316 Anode-cathode distance 30 - 60 mm Anodization time 1.5 min Stirring Not necessary Pre-treatment Not necessary
  • the present method enables improved passivation layers to be obtained and, in particular, layers which are continuous, thin, and very adherent to the substrate, have optimal mechanical characteristics and have different colours so as to enable their application on different base materials, according to the various requirements.
  • the adherent crystalline coating moreover prevents problems of sticking between one coil and another in reels of large dimensions, which in certain cases reach the weight of 10 000 kg or else between plates or laminas set on top of one another, rendering interposition of sheets of paper between one surface and another unnecessary, with benefits from both the economic and environmental standpoints.
  • the compounds and ratios between compounds used as complexing agents in the electrolytic solution may vary, as likewise may vary the conditions of execution of the electrochemical oxidation, such as pH, temperature, applied current density, potential difference, and anodization time.

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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)
  • Electroplating And Plating Baths Therefor (AREA)
EP04001036A 2003-01-21 2004-01-20 Ein Verfahren zur Herstellung einer Passivierungsschicht auf einem Gegenstand mit wenigstens einer Zinn-Oberfläche Withdrawn EP1445352A1 (de)

Applications Claiming Priority (2)

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ITTO20030027 2003-01-21
ITTO20030027 ITTO20030027A1 (it) 2003-01-21 2003-01-21 Metodo per formare uno strato di passivazione su un articolo presentante almeno una superficie stagnata.

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Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2014006031A1 (en) * 2012-07-02 2014-01-09 Tata Steel Ijmuiden Bv Method for producing tinplate and product produced therewith
WO2013104530A3 (de) * 2012-01-12 2014-05-30 Thyssenkrupp Rasselstein Gmbh VERFAHREN ZUR PASSIVIERUNG VON WEIßBLECH
EP2845929A1 (de) * 2013-09-09 2015-03-11 ThyssenKrupp Rasselstein GmbH Mit einer Polymerbeschichtung beschichtetes Weißblech und Verfahren zu dessen Herstellung
JP2017181254A (ja) * 2016-03-30 2017-10-05 古河電気工業株式会社 Ｓｎ被覆材
CN108505080A (zh) * 2018-04-13 2018-09-07 德庆县瑞晶电子材料有限公司 一种用于镀锡产品表面后处理功能的drh-30化合物
CN114460114A (zh) * 2022-04-13 2022-05-10 季华实验室 样品分析方法、装置、设备及存储介质

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB486752A (en) 1936-11-09 1938-06-09 John Campbell Improved process for the treatment of tin and tin alloys and articles made therefrom or coated therewith to protect same against corrosion or chemical action
US2312076A (en) 1939-04-29 1943-02-23 Carnegie Illinois Steel Corp Method of treating tin
GB819305A (en) 1955-11-07 1959-09-02 Ekco Products Company Improvements in or relating to anodic treatment of tin and tin alloys
US3276458A (en) * 1963-01-16 1966-10-04 Arthur H Iversen Ultra pure water recirculating system
GB2020695A (en) * 1978-04-28 1979-11-21 Nippon Kokan Kk Electrolytic tin-plated steel
US4264418A (en) * 1978-09-19 1981-04-28 Kilene Corp. Method for detersifying and oxide coating removal
JPS59222220A (ja) 1983-05-27 1984-12-13 Fuji Electric Corp Res & Dev Ltd キヤリアガスの湿度調整装置
JPS61104099A (ja) * 1984-10-24 1986-05-22 Kawasaki Steel Corp 表面処理鋼板およびその製造方法

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB486752A (en) 1936-11-09 1938-06-09 John Campbell Improved process for the treatment of tin and tin alloys and articles made therefrom or coated therewith to protect same against corrosion or chemical action
US2312076A (en) 1939-04-29 1943-02-23 Carnegie Illinois Steel Corp Method of treating tin
GB819305A (en) 1955-11-07 1959-09-02 Ekco Products Company Improvements in or relating to anodic treatment of tin and tin alloys
US3276458A (en) * 1963-01-16 1966-10-04 Arthur H Iversen Ultra pure water recirculating system
GB2020695A (en) * 1978-04-28 1979-11-21 Nippon Kokan Kk Electrolytic tin-plated steel
US4264418A (en) * 1978-09-19 1981-04-28 Kilene Corp. Method for detersifying and oxide coating removal
JPS59222220A (ja) 1983-05-27 1984-12-13 Fuji Electric Corp Res & Dev Ltd キヤリアガスの湿度調整装置
JPS61104099A (ja) * 1984-10-24 1986-05-22 Kawasaki Steel Corp 表面処理鋼板およびその製造方法

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
DATABASE WPI Section Ch Week 198627, Derwent World Patents Index; Class M14, AN 1986-172372, XP002284379 *
S. A. M. RAFAEY: "Passivation and pitting corrosion of tin in gluconate solutions and the effect of halide ions", JOURNAL OF APPLIED ELECTROCHEMISTRY, vol. 26, 1996, pages 503 - 507

Cited By (11)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2013104530A3 (de) * 2012-01-12 2014-05-30 Thyssenkrupp Rasselstein Gmbh VERFAHREN ZUR PASSIVIERUNG VON WEIßBLECH
CN104040037A (zh) * 2012-01-12 2014-09-10 蒂森克虏拉塞斯坦有限公司 用于钝化白铁皮的方法
AU2012365534B2 (en) * 2012-01-12 2015-08-13 Thyssenkrupp Rasselstein Gmbh Method for passivating tinplate
RU2593248C2 (ru) * 2012-01-12 2016-08-10 ТиссенКрупп Рассельштайн ГмбХ Способ пассивирования белой жести
CN104040037B (zh) * 2012-01-12 2017-08-04 蒂森克虏拉塞斯坦有限公司 用于钝化白铁皮的方法
WO2014006031A1 (en) * 2012-07-02 2014-01-09 Tata Steel Ijmuiden Bv Method for producing tinplate and product produced therewith
EP2845929A1 (de) * 2013-09-09 2015-03-11 ThyssenKrupp Rasselstein GmbH Mit einer Polymerbeschichtung beschichtetes Weißblech und Verfahren zu dessen Herstellung
JP2017181254A (ja) * 2016-03-30 2017-10-05 古河電気工業株式会社 Ｓｎ被覆材
CN108505080A (zh) * 2018-04-13 2018-09-07 德庆县瑞晶电子材料有限公司 一种用于镀锡产品表面后处理功能的drh-30化合物
CN114460114A (zh) * 2022-04-13 2022-05-10 季华实验室 样品分析方法、装置、设备及存储介质
CN114460114B (zh) * 2022-04-13 2022-06-21 季华实验室 样品分析方法、装置、设备及存储介质

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