GB2249320A - Method for post-treatment of plated steel sheet for soldering by applying phosphoric ester - Google Patents
Method for post-treatment of plated steel sheet for soldering by applying phosphoric ester Download PDFInfo
- Publication number
- GB2249320A GB2249320A GB9125633A GB9125633A GB2249320A GB 2249320 A GB2249320 A GB 2249320A GB 9125633 A GB9125633 A GB 9125633A GB 9125633 A GB9125633 A GB 9125633A GB 2249320 A GB2249320 A GB 2249320A
- Authority
- GB
- United Kingdom
- Prior art keywords
- steel sheet
- post
- treatment
- plated steel
- plated
- 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.)
- Granted
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Classifications
-
- C—CHEMISTRY; METALLURGY
- C25—ELECTROLYTIC OR ELECTROPHORETIC PROCESSES; APPARATUS THEREFOR
- C25D—PROCESSES FOR THE ELECTROLYTIC OR ELECTROPHORETIC PRODUCTION OF COATINGS; ELECTROFORMING; APPARATUS THEREFOR
- C25D5/00—Electroplating characterised by the process; Pretreatment or after-treatment of workpieces
- C25D5/48—After-treatment of electroplated surfaces
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B23—MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR
- B23K—SOLDERING OR UNSOLDERING; WELDING; CLADDING OR PLATING BY SOLDERING OR WELDING; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; WORKING BY LASER BEAM
- B23K35/00—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting
- B23K35/22—Rods, electrodes, materials, or media, for use in soldering, welding, or cutting characterised by the composition or nature of the material
- B23K35/36—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest
- B23K35/3612—Selection of non-metallic compositions, e.g. coatings, fluxes; Selection of soldering or welding materials, conjoint with selection of non-metallic compositions, both selections being of interest with organic compounds as principal constituents
-
- C—CHEMISTRY; METALLURGY
- C23—COATING METALLIC MATERIAL; COATING MATERIAL WITH METALLIC MATERIAL; CHEMICAL SURFACE TREATMENT; DIFFUSION TREATMENT OF METALLIC MATERIAL; COATING BY VACUUM EVAPORATION, BY SPUTTERING, BY ION IMPLANTATION OR BY CHEMICAL VAPOUR DEPOSITION, IN GENERAL; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL
- C23F—NON-MECHANICAL REMOVAL OF METALLIC MATERIAL FROM SURFACE; INHIBITING CORROSION OF METALLIC MATERIAL OR INCRUSTATION IN GENERAL; MULTI-STEP PROCESSES FOR SURFACE TREATMENT OF METALLIC MATERIAL INVOLVING AT LEAST ONE PROCESS PROVIDED FOR IN CLASS C23 AND AT LEAST ONE PROCESS COVERED BY SUBCLASS C21D OR C22F OR CLASS C25
- C23F11/00—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent
- C23F11/08—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids
- C23F11/10—Inhibiting corrosion of metallic material by applying inhibitors to the surface in danger of corrosion or adding them to the corrosive agent in other liquids using organic inhibitors
Abstract
Electroplated steel sheet suitable for soldering is provided by providing a coating on the plated steel sheet having a dry thickness in the range of 0.02 to 2 mu m the coating being formed by applying a post-treatment solution containing from 5 to 200 g/l of at least one water-soluble or water-dispersed phosphoric ester. The post-treatment solution may further contain chromium ion, hereafter referred to as Cr<5+>, from 0.01 to 3 g/l, and/or organic amine soap from 10 to 100 g/l. A suitable pH value of the post-treatment solution is from 3 to 10. The steel may be plated with Sn, Pb-Sn, Cu or Zn and specific phosphoric esters used are an alkanolamine salt thereof and an amino salt of mono-(di-oleyl) phosphoric ester.
Description
METHOD FOR POST-TREATMENT OF PLATED STEEL SHEET
FOR SOLDERING
The present invention relates to the post-treatment of plated steel sheet for soldering and especially to the post-treatment solution which exhibits excellent wettability and adhesive strength to solder, hereafter referred to as solderability, as well as excellent corrosion resistance, formability and durability.
Recently, Sn plated steel sheet, Pb-Sn plated steel sheet, Cu plated steel sheet or Zn plated steel sheet have been used as a plated steel sheet suitable for soldering.
However, without post-treatment these plated steel sheets easily corrode during packing or after assembling.
Therefore, post-treatments such as chromate treatment, phosphate treatment or coating with anti-corrosion primer are applied to said steel sheets.
In the case of chromate treatment, it is not suitable because more than 0.1 mg/dm2 of Cur6 is necessary in order to provide sufficient corrosion resistance. However, in the case of more than 0.05 mg/dm of Cr6+, a strong flux is necessary for soldering. The use of strong flux causes deterioration of the working environment and decrease of corrosion resistance of the soldered surface. Therefore, the amount of Cur6 is limited to less than 0.05 mg/dm2 and does not provide sufficient corrosion resistance.
On the other hand, the application of an anti-corrosion primer causes a decrease in solderability similar to chromate treatment and also a decrease in the corrosion resistance of the soldered location.
There is some prior art relating to a process for production of plated steel sheet for soldering, for example,
Japanese Patent Application Laid-Open No. Sho. 61-19793 and
Japanese Patent Application Laid-Open No. Sho. 54-15432.
However, the present invention is different from these inventions with regard to construction and materials used.
Japanese Patent Application Laid-Open No. Sho. 61-19793 relates to a plated steel sheet having excellent solderability that is summarized as follows: Sn or Sn-Pb alloy is plated on the Zn or Zn type alloy plated steel sheet with the amount of deposit from 0.1 to 100 g/m2.
However, the price of Sn is so expensive that the cost of production is high and use of Pb is undesirable from the viewpoint of environmental pollution. The present invention is different from this invention with regard to construction and materials used.
On the other hand, Japanese Patent Application
Laid-Open No. Sho. 54-15432 relates to a post-treatment that is summarized as follows: Zn plated steel sheet is covered with acrylic resin from 0.5 to 20 wn in thickness or paraffin wax from 2 to 20 urn in thickness. The present invention is different from this invention with regard to materials used and effects on solderability and corrosion resistance.
The electroplated steel sheet is provided with a coating having a dry thickness in the range of from 0.02 to 2 ijm, said coating being formed by applying a solution containing from 5 to 200 g/l of at least one water-soluble or water-dispersed phosphoric ester, and
the pH of said solution being from 3 to 10.
The post-treatment solution may further contain 0.01 to 3 g/l of Cr6+ and/or 10 to 100 g/l of organic amine soap.
The detailed method according to the present invention will be described below:
Phosphoric esters including soaps with organic amines or mono-basic or di-basic acids with one or two alkyl groups may be used.
If the alkyl group is large and is not soluble in water, it is possible to add ethylene oxide or neutralize with alkali in order to improve the hydrophilic property.
Phosporic esters can be preferably employed in the range of 5 to 200 g/l and at least one is used.
The effects of the present invention are controlled by the amount of post-treatment coating on the plated sheet, and are not influenced by concentration of post-treatment solution. However, a specified concentration is preferred in order to facilitate operation. Halogen ion is not preferred because it decreases corrosion resistance.
In order to stabilize the post-treatment solution and to improve the corrosion resistance and abrasion resistance, Cur6+ and/or a soap of an organic amine -are used. A concentration of Cur6+ over 3 g/l remarkably decreases solderability and is not suitable.
Soaps of organic amines include dodecylamine, oleoyl imidazoline, aminopropyl beef tallow amine, rosin amine.
The amine may be used as a salt with carbonic acid. The concentration of amine over 100 g/l has some effects on corrosion resistance but less effect on solderability and is not preferred.
Moreover, well-known water-soluble or water-dispersible anti-corrosion agents are available, but in this case, it is important to restrict the amount of addition in order not to decrease the solderability. For example addition of acrylic emulsion increases the abrasion resistance but inversely decreases the solderability.
The pH value of the solution is suitably in the range of from 3 to 10. If the pH of the solution is under 3, the stability of the solution decreases. If the pH of the solution is over 10, drying properties of the post-treatment decrease.
The temperature of the post-treatment is not limited, however, at over B0 C, the stability of the post-treatment solution decreases, resulting in gelation. An ordinary temperature in the range from 20 to 40 C is suitable and economical.
The coating method is not restricted and roll-coating, knife-coating, dipping followed by wringer roll or air-knife treatment are used. The post-treatment product must be sufficiently dry to be handled.
The dry film thickness in the range of 0.02 to 2 urn is suitable. A dry film thickness below 0.02 Wm, has no effects on the corrosion resistance. At a dry film thickness above 2 urn, corrosion resistance increases but solderability does not increase.
In the present invention, the post-treatment solution which may further contain Cur6+ or organic amine soap, can be applied on an Sn plate, Pb-Sn plate, Cu plate or Zn plate.
Solderability and corrosion resistance-bf said steel sheets increase, even after aging. Steel sheets are not restricted to said steel sheet.
The reason why the properties of the coated steel sheet of the present invention improve, has not been clarified.
However, formation of oxides, hydroxides and carbonates is inhibited by coating the present post-treatment solution on said plated steel sheet.
Moreover, it is considered that since the present post-treatment dissolves or reduces the metal oxides which have formed on the plated steel sheet over time, the wetting and diffusion of solder are promoted and solderability is improved. According to said phenomenon, the present post-treatment film covers the plated steel sheet uniformly and increases the corrosion resistance.
The present invention is based on the above-mentioned concept. By coating the present post-treatment solution on the plated steel sheet uniformly, a plated steel sheet having excellent solderability and corrosion resistance can be continuously produced.
Specific embodiments of the present invention are as follows:
METHOD OF EXAMPLES
A cold-rolled steel sheet having thickness of 0.5 mm was used as the substrate and was treated by ordinary alkali cleaning and pickling. After water spraying, the substrates were electroplated in a sulfuric acid bath at the weight of 5 git2 of Zn deposit and were treated in accordance with the present invention. In this regard, a post-treatment solution was coated on the Zn plated steel sheet by a dipping method and the thus-coated steel sheet was dried at the temperature of 60 C to form a coating thereon.
Examples 1-4 of the present invention were treated according to this procedure, with the type and amount of coating being as specified in the Tables.
COMPARATIVE EXAMPLE I
The same substrates as in Example 1 were treated by ordinary alkali cleaning and pickling. After water spraying, the substrate was electroplated in a sulfuric acid bath at the weight of 10 g/m2 of Zn deposit and was electroplated in a phenolsulfonic acid bath (40 C, 30A/d m2) according to Japanese Laid-Open Patent Application No. Sho 61-19793.
Comparative Example 2 was performed according to
Japanese Laid-Open Patent Application No. Sho 54-15432.
Comparative Examples 3-8 were performed according to the same procedure as Comparative Example 2, except for the type and amount of the deposit and post-treatment. The conditions for the post-treatments were summarized in Table 1 and the evaluation of properties was summarized in Tables 2 and 3.
As shown in Tables 2 and 3, post-treatment solution of this invention showed excellent effects on corrosion resistance, solderability and aging tests. Ordinary chemical treatments such as chromate treatment or phosphate treatment (Comparative Examples 3-5) showed effects on corrosion resistance but decreased the we'ttability of the solder particularly after aging. Furthermore, the color of the surface after aging had changed and decreased the corrosion resistance.
Comparative Examples 6 and 7, which contained halogen in the fluxes for soldering, showed poor corrosion resistance and inferior effects on solderability after aging compared to the present post-treatment.
As mentioned in Examples 1- 4 , in Table 1 and 2, excellent corrosion resistance, solderability and formability were obtained and these properties are retained after aging of plated steel sheet. by using the present invention.
Evaluation: The metal substrates which were prepared in
Examples 1- 4 and Comparative Examples 1-8 were evaluated bu the following test methods. The results were shown in
Tables 1 and 2.
(1) Spreadability of solder: a sample steel sheet, 50 x 50 mm in size, was floated on the solder-bath at a temperature of 250 C. The amount of 0.4 g of bended wire solder, that is, resin flux cored solder (JIS Z 3283) was placed on the sample steel sheet for 30 seconds. The area of solder spread was measured after cooling.
#: Area of spread solder > 200mm A 200mm2 > area of spread solder > 50rum2 X: Area of spread solder < 50mm2
(2) Combination strength of solder: a bundle of twenty wires ( =0.18mum) was placed on the test steel sheet and joined with the resin flux solder (RH 50) and was subjected to a pull off test (Bundle of twenty copper wires and solder steel sheet were pulled in opposite directions and evaluated as to the appearance of separated place).
No separation among wire, solder and soldered
0:
steel sheet
Separation between, wire and solder, or solder and soldered steel sheet (3) Corrosion resistance: a sample steel sheet was subjected to 2 cycles of a salt spray test (JIS Z 2371: salt spray 8 hours and dry 16 hours) and evaluated from generation of red rust.
O: No red rust
X: entirely red rust
(4) Formability: sample steel sheets were subjected to the Erichsen test (Er=7 mm) and Du Pont impact test (1/2" x lkg x 30 cm) and were evaluated as to formability by the adhesive tape test.
No separation between plated steel sheet and
0:
post-treatment
Separation between plated steel sheet and
post-treatment
(5) Aging: sample steel sheets were subjected to a thermo-hygrostat(600C, RH 95%) for 1,000 hours and evaluated as to the appearance (or color change), corrosion resistance and solderability in the same way as in evaluations (1)-(4).
Table 1 : Preparation and Condition of Specimens
Amount of Post-treatment Solution Thickness Example Type of Deposit of this invention (g/l) ( m) Plating (g/m) 1 Zn plated 5 phosphoric ester (monobasic) 100 2 CrO3 0.02 2 Zn plated 10 phosphoric ester (mixture of mono- 0.5 and di-basic) 200 mono-(di-oleyl)phosphoric ester 3 Sn plated 5 (amine salt) 10 0.1 CrO3 0.2 4 Sn-Pb phosphoric ester 150 0.2 plated 10 (alkanolamine salt) Compara tive Zn plated 10 Sn plated (according to Japanese Pat.
Example 1 Application No Sho 61-19793) 0.2 2 Zn plated 10 paraffin vax(according to Japanese Pat.
Applicatidn No Sho 54-15432) 100 3 3 Sn plated 5 phosphate treatment 2 g/m as P Sn plated 5 chromate treatment 0.05mg/dm as Cr 5 Cu plated 3 chromate treatment 0.05mg/dm as Cr 6 Zn plated 5 aniline hydrochloride 20 dipping (1 sec.) 7 Zn plated 2 substituted by Sn(IV) chloride 0.05mg/dm for paraffin uax a as Cr 8 Zn plated 10 Table 2 : Evaluation of Characteristics
Sample Corrosion 1 Solderability ormability Change of Number Resistance Spreadability Color Formability Spreadability Strenth 0 0 1 0 0 0 1 2 0 0 0 0 0 3 1 O i -t | 3 0 0 0 0 0 4 0 0 0 0 0 Compare to ampi 1 A-0. 0 / 0 0 A-0 2 Al Al 0 | 0 x x 1 h O X I ,Y [ O | A-0 0 0 0 n 4 X 5 L1 O 0 O X 1X o o 7 1 X | O | 0 | j | X 8 1 O | 101 O O | x Table 3: Evaluation of Characteristics After
1,000 Hours Aging
Sample . Corrosion Solderability Number Resistance I iFormabili ty ormalility 1 '1' 1 0 2 0 0 t O ~ {oj 0 3j 0 | 0. | 0 4 0 0 0 0 4 1 O O | O O - ---- . oj g Comparative| Example 1 n IA X X O 2 A ] X t 3 x X xl 0 4 x | X-A h x-Al O 5 A x I I 6 xl A Al 0 7 A X | O 0 8 X X | A | A Al .0
Claims (6)
1. A method of treating plated steel sheet in preparation for soldering which comprises providing a coating thereon having a dry thickness in the range of from 0.02 to 2 pm, said coating being formed by applying a solution containing from 5 to 200 g/l of at least one water-soluble or water-dispersed phosphoric ester, and
the pH of said solution being from 3 to 10.
2. The method according to claim 1, wherein said solution contains from 0.01 to 3 g/l of Cr6+.
3. The method according to either of claims 1 and 2, wherein the said solution further contains from 10 to 100 g/l of organic amine soap.
4. Plated steel sheets coated with a layer 0.02 to 2 ym in thickness comprised of at least one water-soluble or water-dispersed material as defined in claim 1.
5. The method of treating plated steel sheet as claimed in claim 1 substantially as herein described with reference to any one of the examples.
6. Coated plated steel sheets as claimed in claim 4 substantially as herein described with reference to any one of the examples.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB9125633A GB2249320B (en) | 1987-11-17 | 1991-12-02 | Metod for post-treatment of plated steel sheet for soldering |
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB8726833A GB2212521B (en) | 1986-10-02 | 1987-11-17 | Method for post-treatment of plated steel sheet for soldering |
| GB9125633A GB2249320B (en) | 1987-11-17 | 1991-12-02 | Metod for post-treatment of plated steel sheet for soldering |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB9125633D0 GB9125633D0 (en) | 1992-01-29 |
| GB2249320A true GB2249320A (en) | 1992-05-06 |
| GB2249320B GB2249320B (en) | 1992-07-15 |
Family
ID=10627064
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB9125633A Expired - Lifetime GB2249320B (en) | 1987-11-17 | 1991-12-02 | Metod for post-treatment of plated steel sheet for soldering |
Country Status (1)
| Country | Link |
|---|---|
| GB (1) | GB2249320B (en) |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1054356A (en) * | ||||
| GB1125985A (en) * | 1966-09-01 | 1968-09-05 | Willy Glaser | Improvements in anti-corrosive coatings |
| GB1329198A (en) * | 1970-12-11 | 1973-09-05 | Pyrene Chemical Services Ltd | Conversion coatings |
| JPS53137205A (en) * | 1977-05-04 | 1978-11-30 | Nippon Steel Corp | Oil composition having improved solderability for surface treatment of steel plates |
| GB1554700A (en) * | 1977-04-25 | 1979-10-24 | Pyrene Chemical Services Ltd | Treating metal surfaces |
| JPS54158341A (en) * | 1978-06-05 | 1979-12-14 | Nippon Packaging Kk | Surface treatment of tin plated steel plate and can |
| GB2032963A (en) * | 1978-10-30 | 1980-05-14 | Dart Ind Inc | Non-chromate Conversion Coating Solutions |
-
1991
- 1991-12-02 GB GB9125633A patent/GB2249320B/en not_active Expired - Lifetime
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB1054356A (en) * | ||||
| GB1125985A (en) * | 1966-09-01 | 1968-09-05 | Willy Glaser | Improvements in anti-corrosive coatings |
| GB1329198A (en) * | 1970-12-11 | 1973-09-05 | Pyrene Chemical Services Ltd | Conversion coatings |
| GB1554700A (en) * | 1977-04-25 | 1979-10-24 | Pyrene Chemical Services Ltd | Treating metal surfaces |
| JPS53137205A (en) * | 1977-05-04 | 1978-11-30 | Nippon Steel Corp | Oil composition having improved solderability for surface treatment of steel plates |
| JPS54158341A (en) * | 1978-06-05 | 1979-12-14 | Nippon Packaging Kk | Surface treatment of tin plated steel plate and can |
| GB2032963A (en) * | 1978-10-30 | 1980-05-14 | Dart Ind Inc | Non-chromate Conversion Coating Solutions |
Also Published As
| Publication number | Publication date |
|---|---|
| GB2249320B (en) | 1992-07-15 |
| GB9125633D0 (en) | 1992-01-29 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 19971117 |