JPH0429752B2 - - Google Patents
Info
- Publication number
- JPH0429752B2 JPH0429752B2 JP323685A JP323685A JPH0429752B2 JP H0429752 B2 JPH0429752 B2 JP H0429752B2 JP 323685 A JP323685 A JP 323685A JP 323685 A JP323685 A JP 323685A JP H0429752 B2 JPH0429752 B2 JP H0429752B2
- Authority
- JP
- Japan
- Prior art keywords
- alkali metal
- plated
- plated surface
- buffer consisting
- plating
- 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.)
- Expired
Links
- 238000007747 plating Methods 0.000 claims description 46
- 229910000831 Steel Inorganic materials 0.000 claims description 30
- 239000010959 steel Substances 0.000 claims description 30
- 238000000034 method Methods 0.000 claims description 27
- 238000004090 dissolution Methods 0.000 claims description 19
- -1 alkali metal tetraborate Chemical class 0.000 claims description 16
- 229910052725 zinc Inorganic materials 0.000 claims description 14
- 239000007800 oxidant agent Substances 0.000 claims description 13
- 239000000872 buffer Substances 0.000 claims description 12
- 238000009713 electroplating Methods 0.000 claims description 12
- 229910045601 alloy Inorganic materials 0.000 claims description 10
- 239000000956 alloy Substances 0.000 claims description 10
- 150000003863 ammonium salts Chemical class 0.000 claims description 4
- 239000006258 conductive agent Substances 0.000 claims description 4
- 229910002651 NO3 Inorganic materials 0.000 claims description 3
- NHNBFGGVMKEFGY-UHFFFAOYSA-N Nitrate Chemical compound [O-][N+]([O-])=O NHNBFGGVMKEFGY-UHFFFAOYSA-N 0.000 claims description 3
- 229910052936 alkali metal sulfate Inorganic materials 0.000 claims description 3
- 239000006179 pH buffering agent Substances 0.000 claims description 3
- 239000006174 pH buffer Substances 0.000 claims description 2
- 229910052783 alkali metal Inorganic materials 0.000 claims 14
- 150000008044 alkali metal hydroxides Chemical class 0.000 claims 4
- 229910000288 alkali metal carbonate Inorganic materials 0.000 claims 2
- 150000008041 alkali metal carbonates Chemical class 0.000 claims 2
- 150000001340 alkali metals Chemical class 0.000 claims 2
- 239000003795 chemical substances by application Substances 0.000 claims 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-M dihydrogenphosphate Chemical compound OP(O)([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-M 0.000 claims 2
- 230000003647 oxidation Effects 0.000 claims 1
- 238000007254 oxidation reaction Methods 0.000 claims 1
- 239000010409 thin film Substances 0.000 claims 1
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 14
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 6
- 229910052742 iron Inorganic materials 0.000 description 6
- 238000002844 melting Methods 0.000 description 6
- 230000008018 melting Effects 0.000 description 6
- 230000000694 effects Effects 0.000 description 4
- 238000005868 electrolysis reaction Methods 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- 241000221561 Ustilaginales Species 0.000 description 3
- 229910007567 Zn-Ni Inorganic materials 0.000 description 3
- 229910007614 Zn—Ni Inorganic materials 0.000 description 3
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 description 2
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 description 2
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 2
- 230000002378 acidificating effect Effects 0.000 description 2
- 230000001680 brushing effect Effects 0.000 description 2
- 239000006172 buffering agent Substances 0.000 description 2
- 238000006243 chemical reaction Methods 0.000 description 2
- BNIILDVGGAEEIG-UHFFFAOYSA-L disodium hydrogen phosphate Chemical compound [Na+].[Na+].OP([O-])([O-])=O BNIILDVGGAEEIG-UHFFFAOYSA-L 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 238000002161 passivation Methods 0.000 description 2
- 238000005554 pickling Methods 0.000 description 2
- 238000005498 polishing Methods 0.000 description 2
- 229920006395 saturated elastomer Polymers 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O Ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 1
- MYMOFIZGZYHOMD-UHFFFAOYSA-N Dioxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 description 1
- 229910000990 Ni alloy Inorganic materials 0.000 description 1
- 229910019142 PO4 Inorganic materials 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- BFNBIHQBYMNNAN-UHFFFAOYSA-N ammonium sulfate Chemical compound N.N.OS(O)(=O)=O BFNBIHQBYMNNAN-UHFFFAOYSA-N 0.000 description 1
- 229910052921 ammonium sulfate Inorganic materials 0.000 description 1
- 235000011130 ammonium sulphate Nutrition 0.000 description 1
- 229910021538 borax Inorganic materials 0.000 description 1
- 230000003139 buffering effect Effects 0.000 description 1
- 239000011248 coating agent Substances 0.000 description 1
- 238000000576 coating method Methods 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 238000010668 complexation reaction Methods 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000003111 delayed effect Effects 0.000 description 1
- 229910001882 dioxygen Inorganic materials 0.000 description 1
- XPPKVPWEQAFLFU-UHFFFAOYSA-N diphosphoric acid Chemical compound OP(O)(=O)OP(O)(O)=O XPPKVPWEQAFLFU-UHFFFAOYSA-N 0.000 description 1
- 238000007598 dipping method Methods 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
- 230000005611 electricity Effects 0.000 description 1
- 239000003792 electrolyte Substances 0.000 description 1
- 239000008151 electrolyte solution Substances 0.000 description 1
- 238000005516 engineering process Methods 0.000 description 1
- 239000007789 gas Substances 0.000 description 1
- 230000001771 impaired effect Effects 0.000 description 1
- 238000005259 measurement Methods 0.000 description 1
- 239000000155 melt Substances 0.000 description 1
- BDRTVPCFKSUHCJ-UHFFFAOYSA-N molecular hydrogen;potassium Chemical compound [K].[H][H] BDRTVPCFKSUHCJ-UHFFFAOYSA-N 0.000 description 1
- 229910000402 monopotassium phosphate Inorganic materials 0.000 description 1
- 235000019796 monopotassium phosphate Nutrition 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-M perchlorate Inorganic materials [O-]Cl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-M 0.000 description 1
- VLTRZXGMWDSKGL-UHFFFAOYSA-N perchloric acid Chemical compound OCl(=O)(=O)=O VLTRZXGMWDSKGL-UHFFFAOYSA-N 0.000 description 1
- 239000010452 phosphate Substances 0.000 description 1
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 1
- PJNZPQUBCPKICU-UHFFFAOYSA-N phosphoric acid;potassium Chemical compound [K].OP(O)(O)=O PJNZPQUBCPKICU-UHFFFAOYSA-N 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 238000010079 rubber tapping Methods 0.000 description 1
- 229910000029 sodium carbonate Inorganic materials 0.000 description 1
- 239000004328 sodium tetraborate Substances 0.000 description 1
- 235000010339 sodium tetraborate Nutrition 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 230000000007 visual effect Effects 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
Landscapes
- Electroplating Methods And Accessories (AREA)
Description
〈産業上の利用分野〉
本発明は鋼板または鋼帯のZn又はZn系合金の
片面電気めつきにおいて、非めつき面に廻りこん
で形成されためつき層、又は非めつき面に予め薄
くめつきされためつき層のみを溶解する片面電気
めつき方法に関する。
〈従来の技術〉
両面めつきおよび片面めつきのいずれも製造可
能な電気めつきラインで鋼板または鋼帯の片面め
つきを行う場合、通常めつき面に対向した電極の
みに通電し、片面めつきを行うが、これでは非め
つき面への電流の廻りこみが大きく、非めつき面
にも多量のめつきが行われるため、鋼板または鋼
帯の両端縁部にエツジマスクを取りつけて電流の
廻りこみを防いでいる。しかし、この方法でも完
全ではなく鋼板または鋼帯の非めつき面両端縁部
には約40〜90mm幅でめつきが行われる。このた
め、片面めつき後に、さらにブラツシング等の機
械研摩、又は電解により廻りこみめつきを除去し
ている。
前者については廻りこみめつき層は研削によつ
ては充分に除去できず、かつ、非めつき面にブラ
ツシング模様が発生し、好ましくない。この点、
電解による廻りこみめつきの溶解は確実で、非め
つき面の冷延面も機械的研摩のように粗くなるこ
とはない。また、非めつき面は片面めつき時には
酸性のめつき液と接触しているため冷延面が化学
エツチングをうけ、その結果スマツトが発生して
その後のリン酸塩処理性を損うという観点から非
めつき面にも同時に薄めつきして冷延面を保護
し、めつき後、非めつき面のめつき層を除去する
という方法もある。
このような片面めつきに対しては非めつき面の
めつき層の除去には電解法が有利である。しかし
ながら、通常の電解法、すなわち、鋼板または鋼
帯の非めつき面を陽極に、鋼板または鋼帯の非め
つき面に対向した電極を陰極とする電解ではめつ
き面にも溶解電流が廻りこみめつき面のめつき層
をも溶解してしまう。このため、めつき面にも積
極的に通電し、めつき面を陰極に、非めつき面を
陽極とする電解法が採用されている（特開昭59−
16391）。この方法で電解液のPHをアルカリ性とす
れば非めつき面の冷延面は不動態化し易く、鉄の
溶解を少なくすることができる。
〈発明が解決しようとする問題点〉
しかしながら、この方法にも問題点があり、第
１にめつき面に大電流を流すと水の電気分解が著
しくなる結果としてめつき面上のPHが上昇し、め
つき面のめつき層が徐々に溶解するので、めつき
面の電流は小さくし、非めつき面には短時間溶解
を目的に大電流を流さなくてはならない。このた
め、めつき面への溶解電流の廻りこみがさけられ
ない。第２には電解液がアルカリ性とはいえ、非
めつき面の冷延面の溶解を完全に防止することが
できず、非めつき面の外観を若干ながら損う。第
３には、片面Zn−Ni系合金めつきの場合、非め
つき面のめつき層はZnのみが優先溶解し、Niの
溶解が遅れるため、非めつき面はNiが残存して
しまう。
〈問題点を解決するための手段〉
本発明は間接通電法によりめつき面を陰極に非
めつき面を陽極とし、両面同一の高電流を流すこ
とによつて廻りこみめつき層を溶解させる方法で
あるが、この間接通電法そのものは公知（特公昭
38−4461，U.S.pat.3901771）であり、これを非
めつき面のめつき層の溶解に応用すると、前述し
たような問題点を有するため、本発明はこの廻り
こみめつき層の溶解法を大幅に改良するものであ
る。
具体的には、めつき面においては大電流を流す
ことによつてH2発生量が電流に比例して増え、
めつき面のPHが上昇してめつきを溶解するので、
めつき面におけるPH上昇をPH緩衝剤の添加により
防止する。また非めつき面においては、生成した
めつき層が優先的に溶解し、冷延面は不動態化し
て鉄の溶解を抑制しているものの、非めつき面は
酸素ガスが発生する結果として電解面は弱酸性と
なつており、冷延面の不動態化は完全とはいえ
ず、わずかづつ鉄の溶解が起る。これは浴に酸化
剤を加えることによつて解決される。
Zi−Ni合金めつきの場合のNiの残留はアンモ
ニウムイオンを加えてNiの錯化を計ることによ
つてNiの溶解を促進する。
〈発明の構成〉
本発明によれば鋼板または鋼帯にZnまたはZn
系合金を片面に電気めつきする方法であつて、鋼
板または鋼帯の片面のみに、または片面のみなら
ず非めつき面にも５ｇ／m2未満の薄めつきを施し
た後に、浴のPHを６〜11に維持するPH緩衝剤と酸
化剤を含む電解浴中で、非めつき面を陽極とし、
めつき面を陰極とする間接通電を行ない、めつき
面のめつき層を溶解せずに非めつき面の回り込み
めつき層、又は薄いめつき層を溶解し、かつ冷延
面のFeの溶解を抑制することを特徴とする片面
電気めつき法が提供される。
さらに本発明によれば鋼板または鋼帯にZnま
たはZn系合金を片面に電気めつきする方法であ
つて、鋼板または鋼帯の片面のみに、または片面
のみならず非めつき面にも５ｇ／m2未満の薄めつ
きを施した後に、浴のPHを６〜11に維持するPH緩
衝剤と酸化剤とアンモニウム塩を含む浴中で、非
めつき面を陽極とし、めつき面を陰極とする間接
通電を行ない、めつき面のめつき層を溶解せずに
非めつき面の回り込みめつき層、又は薄いめつき
層を溶解し、かつ冷延面のFeの溶解を抑制する
ことを特徴とする片面電気めつき法が提供され
る。
すなわち、めつき層の溶解はPH12以上において
起ることから、PH６〜11の範囲において緩衝作用
を有する緩衝剤、具体的には例えば４ホウ酸ナト
リウムと水酸化ナトリウムの組み合せ、リン酸水
素２ナトリウムと水酸化ナトリウムの組み合せ、
炭酸ナトリウムと炭素水素ナトリウムの組み合
せ、リン酸２水素カリウムと炭酸水素ナトリウム
の組み合せ、リン酸水素２ナトリウムとリン酸２
水素カリウムの組み合せのいずれか１種の緩衝剤
を添加し、これによつてめつき面の電解界面のPH
上昇を抑制する。
本発明の方法においては冷延面の不動態化を達
成するために酸化剤を加える。硝酸塩、過塩素酸
塩又は過マンガン酸塩のいずれかであり、これに
より冷延面の不動態化を完全なものとし、鉄の溶
解は防止される。
また、Zn−Ni系合金片面電気めつきにおいて
は、前述のように非めつき面のめつき中でZnの
溶解は容易なものの、Niの溶解が遅く非めつき
面にはNiが残存し易い。このため、本発明はさ
らに硫酸アンモニウムのようなアンモニウムイオ
ン源を添加し、ニツケルとアンモニウムイオンと
の化学反応（錯化）によりニツケルの溶解を促進
するものである。
なお上記PH緩衝剤や酸化剤のみでは電気伝導性
が不十分である場合には、電導剤を加える。電解
浴の好ましい電導剤は硫酸アルカリ金属である。
これはめつき浴が硫酸塩浴であり、上記硫酸塩の
添加は片面溶解性にほとんど影響を及ぼさない。
これによりめつき面の溶解を最少に抑え非めつ
き面の残留めつきはほとんどなく、ほぼ完全な片
面めつきをえることができる。
さらに、本発明は酸洗やめつき工程で発生した
非めつき面（冷延面）のスマツトをも除去するこ
とができ、その後の化成性を損うことはない。こ
れは、非めつき面の発生ガスにより付着したスマ
ツトが除去されるものであろうと推定される。
ここで、PH緩衝の範囲を６〜11としたのは、６
未満では非めつき面の電解面のPHが低くなりす
ぎ、酸化剤を添加しても冷延面の溶解が抑制でき
ないからで、PHが11を越えると大電流による処理
において、めつき面の電解面のPHが12以上となり
めつき面のめつき溶解が起るからである。また、
酸化剤の添加量を0.1〜0.5モル／としたのは、
0.1モル／未満では酸化剤の効果が小さく、冷
延面の溶解を完全に抑制できず、0.5モル／を
こえると酸化剤の効果は飽和となり、これ以上の
添加は意味がないからである。つぎに、アンモニ
ウム塩の添加量を0.1〜１モル／としたのは、
0.1モル／未満では、アンモニウムイオンによ
るNiの化学溶解を促進することが不十分で、非
めつき面に微量ながらNiが残留してしまい、１
モル／をこえると、アンモニウムイオンによる
Niの化学溶解の促進はほぼ飽和となり、これ以
上の添加は意味がないからである。
〈実施態様〉
以下、実施例に従い説明する。
実施例
0.8t×300wの冷延鋼帯を通常の方法で脱脂、酸
洗した後、めつき面に対向した電極との間で片面
Znめつきおよび片面Zn−Ni合金めつきを行つ
た。めつき面のめつき付着量は35ｇ／m2である。
また、片面Znめつき製品の１部については非め
つき面に２ｇ／m2の薄めつきを行つた。しかる
後、第１表に示す電解条件で非めつき面のめつき
が目視で完全に溶解する時間まで電解した。
これらの各試料についてめつき面のめつき付着
量の分析（本発明処理前後の付着量差からみため
つき面のめつきの溶解量測定）、非めつき面の廻
りこみめつきの残存量および非めつき面冷延面の
鉄の溶解（目視外観による光沢性）を調査した。
結果を第２表に示す。
<Industrial Field of Application> The present invention is applicable to single-sided electroplating of Zn or Zn-based alloys on steel plates or steel strips, and is applied to a dipping layer formed around the non-plated surface, or a pre-thin coating on the non-plated surface. The present invention relates to a single-sided electroplating method in which only the applied plating layer is dissolved. <Conventional technology> When plating one side of a steel plate or steel strip on an electroplating line that can produce both double-sided plating and single-sided plating, normally only the electrode facing the plated surface is energized, and single-sided plating is performed. However, in this case, the current flows around the non-plated surface to a large extent, and a large amount of plating is also performed on the non-plated surface, so edge masks are attached to both edges of the steel plate or steel strip to prevent the current from flowing Prevents stains. However, even with this method, plating is not perfect, and both edges of the non-plated surface of the steel plate or steel strip are plated in a width of about 40 to 90 mm. For this reason, after single-sided plating, the wrap-around plating is further removed by mechanical polishing such as brushing or electrolysis. In the former case, the wrap-around plated layer cannot be sufficiently removed by grinding, and a brushing pattern appears on the non-plated surface, which is not preferable. In this point,
The electrolytic process ensures that the rolling plating is dissolved, and the non-plated cold-rolled surface does not become rough unlike mechanical polishing. In addition, since the non-plated surface is in contact with acidic plating solution during single-sided plating, the cold-rolled surface is chemically etched, resulting in smuts that impair subsequent phosphate treatment. Another method is to protect the cold-rolled surface by simultaneously applying thinning to the non-plated surface, and then removing the plated layer on the non-plated surface after plating. For such single-sided plating, electrolysis is advantageous for removing the plated layer on the non-plated side. However, in the normal electrolytic method, in which the non-plated surface of the steel plate or steel strip is used as the anode and the electrode facing the non-plated surface of the steel plate or steel strip is used as the cathode, the dissolution current also circulates on the plated surface. It also dissolves the plating layer on the matted surface. For this reason, an electrolytic method has been adopted in which electricity is actively applied to the plated surface, and the plated surface is used as a cathode and the non-plated surface is used as an anode.
16391). If the PH of the electrolyte is made alkaline using this method, the non-plated cold-rolled surface will be easily passivated and the dissolution of iron can be reduced. <Problems to be solved by the invention> However, this method also has problems. First, when a large current is passed through the plated surface, the electrolysis of water becomes significant, resulting in an increase in the pH on the plated surface. However, since the plated layer on the plated surface gradually dissolves, the current must be kept small on the plated surface, and a large current must be applied to the non-plated surface for the purpose of short-term melting. For this reason, it is unavoidable that the melting current flows around to the plated surface. Second, although the electrolytic solution is alkaline, it cannot completely prevent the cold-rolled surface of the non-plated surface from dissolving, and the appearance of the non-plated surface is slightly impaired. Thirdly, in the case of single-sided Zn-Ni alloy plating, only Zn preferentially dissolves in the plating layer on the non-plated surface, and the dissolution of Ni is delayed, so Ni remains on the non-plated surface. <Means for Solving the Problems> The present invention uses an indirect energization method to make the plated surface a cathode and the non-plated surface an anode, and by passing the same high current on both sides, the circumferential plated layer is dissolved. However, this indirect energization method itself is publicly known (Tokuko Showa).
38-4461, USpat. 3901771), and if this method is applied to melting a plated layer on a non-plated surface, the above-mentioned problems arise. This is a major improvement. Specifically, when a large current is applied to a plated surface, the amount of H2 generated increases in proportion to the current.
As the pH of the plated surface increases and dissolves the plating,
Prevent PH increase on the plated surface by adding a PH buffer. In addition, on the non-plated surface, the formed tapping layer dissolves preferentially, and while the cold-rolled surface becomes passivated and suppresses the dissolution of iron, the non-plated surface is affected by the generation of oxygen gas. The electrolytic surface is slightly acidic, and the passivation of the cold-rolled surface is not complete, and iron gradually dissolves. This is solved by adding an oxidizing agent to the bath. When Ni remains in the case of Zi-Ni alloy plating, dissolution of Ni is promoted by adding ammonium ions to complex Ni. <Configuration of the Invention> According to the present invention, Zn or Zn is added to the steel plate or steel strip.
This is a method of electroplating a steel plate or steel strip on one side, or after applying a thin plating of less than 5 g/m 2 not only to one side but also to the non-plated side. In an electrolytic bath containing a pH buffer and oxidizing agent that maintains the pH between 6 and 11, the non-plated surface is used as the anode,
By applying indirect current using the plated surface as a cathode, it melts the wrap-around plated layer or thin plated layer on the non-plated surface without dissolving the plated layer on the plated surface, and removes Fe on the cold-rolled surface. A single-sided electroplating method is provided that is characterized by suppressing dissolution. Further, according to the present invention, there is provided a method of electroplating Zn or Zn-based alloy on one side of a steel plate or steel strip, and the method includes electroplating Zn or Zn-based alloy on one side of the steel plate or steel strip, or not only on one side but also on the non-plated side. After thinning to less than m 2 , the non-plated side is used as an anode and the plated side is used as a cathode in a bath containing a pH buffer, an oxidizing agent, and an ammonium salt to maintain the pH of the bath between 6 and 11. It is possible to melt the wraparound plating layer or thin plating layer on the non-plated surface without dissolving the plating layer on the plated surface, and to suppress the dissolution of Fe on the cold-rolled surface. A featured single-sided electroplating method is provided. That is, since the dissolution of the plating layer occurs at a pH of 12 or higher, buffering agents that have a buffering effect in the pH range of 6 to 11, specifically, for example, a combination of sodium tetraborate and sodium hydroxide, or disodium hydrogen phosphate, are used. A combination of and sodium hydroxide,
Combination of sodium carbonate and sodium bicarbonate, combination of potassium dihydrogen phosphate and sodium bicarbonate, disodium hydrogen phosphate and diphosphoric acid
By adding one of the buffering agents of the combination of potassium hydrogen and potassium, this will reduce the pH of the electrolytic interface on the plated surface.
Control the rise. In the method of the invention, an oxidizing agent is added to achieve passivation of the cold rolled surface. Either nitrate, perchlorate or permanganate, which completely passivates the cold rolled surface and prevents dissolution of the iron. In addition, in single-sided electroplating of Zn-Ni alloys, as mentioned above, although Zn easily dissolves during plating on the non-plated side, the dissolution of Ni is slow and Ni remains on the non-plated side. easy. For this reason, the present invention further adds an ammonium ion source such as ammonium sulfate to promote the dissolution of nickel through a chemical reaction (complexation) between nickel and ammonium ions. Note that if the electrical conductivity is insufficient with only the above-mentioned PH buffer or oxidizing agent, a conductive agent is added. The preferred conductive agent for the electrolytic bath is an alkali metal sulfate.
The plating bath is a sulfate bath, and the addition of the sulfate has little effect on one-sided solubility. This minimizes melting of the plated surface, leaves almost no residual sticking on the non-plated surface, and provides almost perfect one-sided plating. Furthermore, the present invention can also remove smuts on the non-plated surface (cold-rolled surface) generated during the pickling and plating steps, without impairing the subsequent chemical formability. It is presumed that this is because the adhered smut is removed by the gas generated on the non-plated surface. Here, the range of PH buffer is set to 6 to 11.
If the pH is less than 11, the PH of the electrolytic surface on the non-plated surface will be too low, and melting of the cold-rolled surface cannot be suppressed even if an oxidizing agent is added. This is because when the pH of the electrolytic surface becomes 12 or higher, plating and dissolution of the plating surface occur. Also,
The reason why the amount of oxidizing agent added was 0.1 to 0.5 mol/
This is because if the amount is less than 0.1 mol/mol, the effect of the oxidizing agent is small and dissolution of the cold-rolled surface cannot be completely suppressed, and if it exceeds 0.5 mol//, the effect of the oxidizing agent becomes saturated, and there is no point in adding more than this. Next, the amount of ammonium salt added was set to 0.1 to 1 mol/
If it is less than 0.1 mol/mol, it is insufficient to promote the chemical dissolution of Ni by ammonium ions, and a small amount of Ni will remain on the non-plated surface.
If it exceeds mol/, it is caused by ammonium ions.
This is because the promotion of chemical dissolution of Ni is almost saturated, and there is no point in adding any more. <Embodiments> Hereinafter, explanations will be given according to examples. Example: After degreasing and pickling a 0.8t x 300w cold-rolled steel strip using the usual method, one side was coated with an electrode opposite the plated surface.
Zn plating and single-sided Zn-Ni alloy plating were performed. The amount of plating on the plated surface was 35 g/m 2 .
In addition, for a part of the single-sided Zn-plated product, the non-plated surface was thinned to 2 g/m 2 . Thereafter, electrolysis was carried out under the electrolytic conditions shown in Table 1 until the plating on the non-plated surface was visually completely dissolved. For each of these samples, analysis of the amount of plating on the plated surface (measurement of the amount of dissolution of the plating on the plated surface based on the difference in the amount of plating before and after the treatment of the present invention), the remaining amount of wrap-around plating on the non-plated surface, and the amount of plating on the non-plated surface were analyzed. The dissolution of iron on the cold-rolled surface (brightness by visual appearance) was investigated.
The results are shown in Table 2.
【表】【table】
【表】【table】
【表】【table】
【表】
つき面のめつき残存量はめつき鋼板を幅方向
に分析し、その平均値として算出した。
第２表から明らかなように、本発明はめつき面
のめつきをほとんど溶解することなく、非めつき
面においては廻りこみめつきをほぼ完全に溶解で
きると共に、冷延面の鉄の溶解を抑制することが
できる。
〈効果〉
このように、本発明によれば、片面Znめつき
又は片面Zn系合金めつきにおいて、従来よりも
優れた片面めつき鋼帯をえることができる。又、
本発明は非めつき面の冷延面に付着しているスマ
ツトをも除去できることから、その後の化成処理
性についても優れていることはいうまでもない。[Table] The remaining amount of plating on the plated surface was calculated as the average value of the plated steel plates analyzed in the width direction.
As is clear from Table 2, the present invention can almost completely dissolve the wrap-around plating on the non-plated surface without dissolving the plating on the plated surface, and can prevent the melting of iron on the cold-rolled surface. Can be suppressed. <Effects> As described above, according to the present invention, it is possible to obtain a single-sided plated steel strip that is superior to the conventional one in single-sided Zn plating or single-sided Zn-based alloy plating. or,
Since the present invention can also remove smuts adhering to the non-plated cold-rolled surface, it goes without saying that it is also excellent in subsequent chemical conversion treatment.
Claims (1)
に電気めつきする方法であつて、鋼板または鋼帯
の片面のみに、または片面のみならず非めつき面
にも５ｇ／m2未満の薄めつきを施した後に、浴の
PHを６〜11に維持するPH緩衝剤と酸化剤を含む電
解浴中で、非めつき面を陽極とし、めつき面を陰
極とする間接通電を行ない、めつき面のめつき層
を溶解せずに非めつき面の回り込みめつき層、又
は薄いめつき層を溶解し、かつ冷延面のFeの溶
解を抑制することを特徴とする片面電気めつき
法。 ２ 特許請求の範囲第１項に記載の方法であつ
て、電解浴が４ホウ酸アルカリ金属と水酸化アル
カリ金属からなるPH緩衝剤、リン酸水素２アルカ
リ金属と水酸化アルカリ金属からなるPH緩衝剤、
炭酸アルカリ金属と炭酸水素アルカリ金属からな
るPH緩衝剤、リン酸２水素アルカリ金属と炭酸水
素アルカリ金属からなるPH緩衝剤、リン酸水素２
アルカリ金属とリン酸２水素アルカリ金属からな
るPH緩衝剤のいずれかと酸化剤としての0.1〜0.5
モル／の硝酸塩または過マンガン酸塩を含む方
法。 ３ 特許請求の範囲第１項に記載の方法であつ
て、電解浴の電導剤が硫酸アルカリ金属である方
法。 ４ 鋼板または鋼帯にZnまたはZn系合金を片面
に電気めつきする方法であつて、鋼板または鋼帯
の片面のみに、または片面のみならず非めつき面
にも５ｇ／m2未満の薄めつきを施した後に、浴の
PHを６〜11に維持するPH緩衝剤と酸化剤とアンモ
ニウム塩を含む浴中で、非めつき面を陽極とし、
めつき面を陰極とする間接通電を行ない、めつき
面のめつき層を溶解せずに非めつき面の回り込み
めつき層、又は薄いめつき層を溶解し、かつ冷延
面のFeの溶解を抑制することを特徴とする片面
電気めつき法。 ５ 特許請求の範囲第４項に記載の方法であつ
て、電解浴が４ホウ酸アルカリ金属と水酸化アル
カリ金属からなるPH緩衝剤、リン酸水素２アルカ
リ金属と水酸化アルカリ金属からなるPH緩衝剤、
炭酸アルカリ金属と炭酸水素アルカリ金属からな
るPH緩衝剤、リン酸２水素アルカリ金属と炭酸水
素アルカリ金属からなるPH緩衝剤、リン酸水素２
アルカリ金属とリン酸２水素アルカリ金属からな
るPH緩衝剤のいずれかと、酸化剤として0.1〜0.5
モル／の硝酸塩または過マンガン酸塩と、アン
モニウム塩を含む方法。 ６ 特許請求の範囲第５項に記載の方法であつ
て、電解浴の電導剤が硫酸アルカリ金属である方
法。[Claims] 1. A method of electroplating Zn or Zn-based alloy on one side of a steel plate or steel strip, in which 5g of Zn or Zn-based alloy is electroplated on only one side of the steel plate or steel strip, or not only on one side but also on the non-plated side. / m 2 After applying the thinning, the bath
In an electrolytic bath containing a pH buffer and oxidizing agent that maintains the pH between 6 and 11, indirect current is applied using the non-plated surface as the anode and the plated surface as the cathode to dissolve the plated layer on the plated surface. 1. A single-side electroplating method characterized by dissolving a wrap-around plating layer or a thin plating layer on a non-plated surface without oxidation, and suppressing dissolution of Fe on a cold-rolled surface. 2. The method according to claim 1, wherein the electrolytic bath is a PH buffer consisting of an alkali metal tetraborate and an alkali metal hydroxide, a PH buffer consisting of an alkali metal hydrogen phosphate and an alkali metal hydroxide. agent,
PH buffer consisting of alkali metal carbonate and alkali metal hydrogen carbonate, PH buffer consisting of alkali metal dihydrogen phosphate and alkali metal hydrogen carbonate, dihydrogen phosphate
Either a PH buffer consisting of an alkali metal or an alkali metal dihydrogen phosphate and 0.1 to 0.5 as an oxidizing agent.
Methods involving mol/mole of nitrate or permanganate. 3. The method according to claim 1, wherein the conductive agent in the electrolytic bath is an alkali metal sulfate. 4 A method in which Zn or Zn-based alloy is electroplated on one side of a steel plate or steel strip, and a thin film of less than 5 g/m 2 is applied only to one side of the steel plate or steel strip, or not only to one side but also to the non-plated surface. After applying the tsuki, take a bath.
In a bath containing a pH buffer, an oxidizing agent, and an ammonium salt to maintain the pH between 6 and 11, the non-plated surface is used as an anode.
An indirect current is applied using the plated surface as a cathode, and the wraparound plated layer or thin plated layer on the non-plated surface is melted without dissolving the plated layer on the plated surface, and the Fe on the cold-rolled surface is melted. A single-sided electroplating method characterized by suppressing dissolution. 5. The method according to claim 4, wherein the electrolytic bath is a PH buffer consisting of an alkali metal tetraborate and an alkali metal hydroxide, a PH buffer consisting of an alkali metal hydrogen phosphate and an alkali metal hydroxide. agent,
PH buffer consisting of alkali metal carbonate and alkali metal hydrogen carbonate, PH buffer consisting of alkali metal dihydrogen phosphate and alkali metal hydrogen carbonate, dihydrogen phosphate
Either a PH buffer consisting of an alkali metal or an alkali metal dihydrogen phosphate, and 0.1 to 0.5 as an oxidizing agent.
mol/mole of nitrate or permanganate and an ammonium salt. 6. The method according to claim 5, wherein the conductive agent in the electrolytic bath is an alkali metal sulfate.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP323685A JPS61163292A (en) | 1985-01-14 | 1985-01-14 | One-side electroplating method |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP323685A JPS61163292A (en) | 1985-01-14 | 1985-01-14 | One-side electroplating method |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS61163292A JPS61163292A (en) | 1986-07-23 |
| JPH0429752B2 true JPH0429752B2 (en) | 1992-05-19 |
Family
ID=11551815
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP323685A Granted JPS61163292A (en) | 1985-01-14 | 1985-01-14 | One-side electroplating method |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS61163292A (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105671605A (en) * | 2015-12-28 | 2016-06-15 | 银邦金属复合材料股份有限公司 | Manufacturing method for single-side-aluminum-coated steel plates |
-
1985
- 1985-01-14 JP JP323685A patent/JPS61163292A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS61163292A (en) | 1986-07-23 |
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