JPH0210236B2 - - Google Patents
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- Publication number
- JPH0210236B2 JPH0210236B2 JP13609982A JP13609982A JPH0210236B2 JP H0210236 B2 JPH0210236 B2 JP H0210236B2 JP 13609982 A JP13609982 A JP 13609982A JP 13609982 A JP13609982 A JP 13609982A JP H0210236 B2 JPH0210236 B2 JP H0210236B2
- Authority
- JP
- Japan
- Prior art keywords
- plating
- alloy
- layer
- amount
- 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.)
- Expired
Links
- 238000007747 plating Methods 0.000 claims description 103
- 238000005260 corrosion Methods 0.000 claims description 44
- 230000007797 corrosion Effects 0.000 claims description 42
- 229910000831 Steel Inorganic materials 0.000 claims description 41
- 239000010959 steel Substances 0.000 claims description 41
- 229910020515 Co—W Inorganic materials 0.000 claims description 36
- 229910000599 Cr alloy Inorganic materials 0.000 claims description 33
- 239000000956 alloy Substances 0.000 claims description 31
- 229910045601 alloy Inorganic materials 0.000 claims description 31
- 229910052725 zinc Inorganic materials 0.000 claims description 28
- 229910052721 tungsten Inorganic materials 0.000 claims description 16
- 229910052804 chromium Inorganic materials 0.000 claims description 14
- 238000009713 electroplating Methods 0.000 claims description 9
- 238000004519 manufacturing process Methods 0.000 claims description 4
- 229910017052 cobalt Inorganic materials 0.000 claims description 3
- 239000010941 cobalt Substances 0.000 claims description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims description 3
- 239000011701 zinc Substances 0.000 description 51
- 239000010410 layer Substances 0.000 description 43
- 239000011651 chromium Substances 0.000 description 19
- 230000000694 effects Effects 0.000 description 16
- 239000011248 coating agent Substances 0.000 description 14
- 238000000576 coating method Methods 0.000 description 14
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 12
- 238000012360 testing method Methods 0.000 description 12
- 229910019142 PO4 Inorganic materials 0.000 description 9
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 9
- 239000010452 phosphate Substances 0.000 description 9
- 238000000034 method Methods 0.000 description 8
- 239000000203 mixture Substances 0.000 description 8
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 8
- 235000019270 ammonium chloride Nutrition 0.000 description 6
- 238000004070 electrodeposition Methods 0.000 description 6
- 229910052751 metal Inorganic materials 0.000 description 6
- 238000010422 painting Methods 0.000 description 6
- 239000002131 composite material Substances 0.000 description 5
- 239000013078 crystal Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 238000012545 processing Methods 0.000 description 5
- 230000001681 protective effect Effects 0.000 description 5
- NBIIXXVUZAFLBC-UHFFFAOYSA-N Phosphoric acid Chemical compound OP(O)(O)=O NBIIXXVUZAFLBC-UHFFFAOYSA-N 0.000 description 4
- 229910007567 Zn-Ni Inorganic materials 0.000 description 4
- 229910007614 Zn—Ni Inorganic materials 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 4
- KGBXLFKZBHKPEV-UHFFFAOYSA-N boric acid Chemical compound OB(O)O KGBXLFKZBHKPEV-UHFFFAOYSA-N 0.000 description 4
- 239000004327 boric acid Substances 0.000 description 4
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 4
- 235000002639 sodium chloride Nutrition 0.000 description 4
- 235000005074 zinc chloride Nutrition 0.000 description 4
- 239000011592 zinc chloride Substances 0.000 description 4
- UGZADUVQMDAIAO-UHFFFAOYSA-L zinc hydroxide Chemical compound [OH-].[OH-].[Zn+2] UGZADUVQMDAIAO-UHFFFAOYSA-L 0.000 description 4
- 229940007718 zinc hydroxide Drugs 0.000 description 4
- 229910021511 zinc hydroxide Inorganic materials 0.000 description 4
- 229910021555 Chromium Chloride Inorganic materials 0.000 description 3
- 229910000640 Fe alloy Inorganic materials 0.000 description 3
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 description 3
- KRKNYBCHXYNGOX-UHFFFAOYSA-N citric acid Chemical compound OC(=O)CC(O)(C(O)=O)CC(O)=O KRKNYBCHXYNGOX-UHFFFAOYSA-N 0.000 description 3
- 238000011156 evaluation Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000007921 spray Substances 0.000 description 3
- 238000003466 welding Methods 0.000 description 3
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 2
- WGLPBDUCMAPZCE-UHFFFAOYSA-N Trioxochromium Chemical compound O=[Cr](=O)=O WGLPBDUCMAPZCE-UHFFFAOYSA-N 0.000 description 2
- 229910007570 Zn-Al Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 229910000147 aluminium phosphate Inorganic materials 0.000 description 2
- 125000002091 cationic group Chemical group 0.000 description 2
- 150000001845 chromium compounds Chemical class 0.000 description 2
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 2
- 229910000361 cobalt sulfate Inorganic materials 0.000 description 2
- 229940044175 cobalt sulfate Drugs 0.000 description 2
- KTVIXTQDYHMGHF-UHFFFAOYSA-L cobalt(2+) sulfate Chemical compound [Co+2].[O-]S([O-])(=O)=O KTVIXTQDYHMGHF-UHFFFAOYSA-L 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 238000000151 deposition Methods 0.000 description 2
- 230000008021 deposition Effects 0.000 description 2
- 230000006866 deterioration Effects 0.000 description 2
- 230000005611 electricity Effects 0.000 description 2
- 229910052742 iron Inorganic materials 0.000 description 2
- 150000002739 metals Chemical class 0.000 description 2
- 229910052759 nickel Inorganic materials 0.000 description 2
- 239000003973 paint Substances 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- XMVONEAAOPAGAO-UHFFFAOYSA-N sodium tungstate Chemical compound [Na+].[Na+].[O-][W]([O-])(=O)=O XMVONEAAOPAGAO-UHFFFAOYSA-N 0.000 description 2
- PBYZMCDFOULPGH-UHFFFAOYSA-N tungstate Chemical compound [O-][W]([O-])(=O)=O PBYZMCDFOULPGH-UHFFFAOYSA-N 0.000 description 2
- 229910052720 vanadium Inorganic materials 0.000 description 2
- 229910052726 zirconium Inorganic materials 0.000 description 2
- TUSDEZXZIZRFGC-UHFFFAOYSA-N 1-O-galloyl-3,6-(R)-HHDP-beta-D-glucose Natural products OC1C(O2)COC(=O)C3=CC(O)=C(O)C(O)=C3C3=C(O)C(O)=C(O)C=C3C(=O)OC1C(O)C2OC(=O)C1=CC(O)=C(O)C(O)=C1 TUSDEZXZIZRFGC-UHFFFAOYSA-N 0.000 description 1
- OYPRJOBELJOOCE-UHFFFAOYSA-N Calcium Chemical compound [Ca] OYPRJOBELJOOCE-UHFFFAOYSA-N 0.000 description 1
- 239000001263 FEMA 3042 Substances 0.000 description 1
- ZOKXTWBITQBERF-UHFFFAOYSA-N Molybdenum Chemical compound [Mo] ZOKXTWBITQBERF-UHFFFAOYSA-N 0.000 description 1
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 1
- LRBQNJMCXXYXIU-PPKXGCFTSA-N Penta-digallate-beta-D-glucose Natural products OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-PPKXGCFTSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
- RTAQQCXQSZGOHL-UHFFFAOYSA-N Titanium Chemical compound [Ti] RTAQQCXQSZGOHL-UHFFFAOYSA-N 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- QCWXUUIWCKQGHC-UHFFFAOYSA-N Zirconium Chemical compound [Zr] QCWXUUIWCKQGHC-UHFFFAOYSA-N 0.000 description 1
- 238000010306 acid treatment Methods 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 239000000654 additive Substances 0.000 description 1
- 229910052782 aluminium Inorganic materials 0.000 description 1
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 description 1
- WNROFYMDJYEPJX-UHFFFAOYSA-K aluminium hydroxide Chemical compound [OH-].[OH-].[OH-].[Al+3] WNROFYMDJYEPJX-UHFFFAOYSA-K 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 235000010338 boric acid Nutrition 0.000 description 1
- 229910052791 calcium Inorganic materials 0.000 description 1
- 239000011575 calcium Substances 0.000 description 1
- 238000006243 chemical reaction Methods 0.000 description 1
- 239000003795 chemical substances by application Substances 0.000 description 1
- ZCDOYSPFYFSLEW-UHFFFAOYSA-N chromate(2-) Chemical compound [O-][Cr]([O-])(=O)=O ZCDOYSPFYFSLEW-UHFFFAOYSA-N 0.000 description 1
- GRWVQDDAKZFPFI-UHFFFAOYSA-H chromium(III) sulfate Chemical compound [Cr+3].[Cr+3].[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O.[O-]S([O-])(=O)=O GRWVQDDAKZFPFI-UHFFFAOYSA-H 0.000 description 1
- 238000004140 cleaning Methods 0.000 description 1
- 150000001868 cobalt Chemical class 0.000 description 1
- WLQXLCXXAPYDIU-UHFFFAOYSA-L cobalt(2+);disulfamate Chemical compound [Co+2].NS([O-])(=O)=O.NS([O-])(=O)=O WLQXLCXXAPYDIU-UHFFFAOYSA-L 0.000 description 1
- JECJVZVHLPZRNM-UHFFFAOYSA-J cobalt(2+);phosphonato phosphate Chemical compound [Co+2].[Co+2].[O-]P([O-])(=O)OP([O-])([O-])=O JECJVZVHLPZRNM-UHFFFAOYSA-J 0.000 description 1
- SCNCIXKLOBXDQB-UHFFFAOYSA-K cobalt(3+);2-hydroxypropane-1,2,3-tricarboxylate Chemical compound [Co+3].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O SCNCIXKLOBXDQB-UHFFFAOYSA-K 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 239000002482 conductive additive Substances 0.000 description 1
- 229910052802 copper Inorganic materials 0.000 description 1
- 230000007423 decrease Effects 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- AAQNGTNRWPXMPB-UHFFFAOYSA-N dipotassium;dioxido(dioxo)tungsten Chemical compound [K+].[K+].[O-][W]([O-])(=O)=O AAQNGTNRWPXMPB-UHFFFAOYSA-N 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 238000007710 freezing Methods 0.000 description 1
- 230000008014 freezing Effects 0.000 description 1
- 238000007602 hot air drying Methods 0.000 description 1
- -1 hydroxyl ions Chemical class 0.000 description 1
- 229910052738 indium Inorganic materials 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- 230000007774 longterm Effects 0.000 description 1
- 229910052749 magnesium Inorganic materials 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910052750 molybdenum Inorganic materials 0.000 description 1
- 239000011733 molybdenum Substances 0.000 description 1
- GEMHFKXPOCTAIP-UHFFFAOYSA-N n,n-dimethyl-n'-phenylcarbamimidoyl chloride Chemical compound CN(C)C(Cl)=NC1=CC=CC=C1 GEMHFKXPOCTAIP-UHFFFAOYSA-N 0.000 description 1
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 230000000149 penetrating effect Effects 0.000 description 1
- 238000011056 performance test Methods 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 239000001103 potassium chloride Substances 0.000 description 1
- 235000011164 potassium chloride Nutrition 0.000 description 1
- 230000001376 precipitating effect Effects 0.000 description 1
- 230000002265 prevention Effects 0.000 description 1
- 230000003449 preventive effect Effects 0.000 description 1
- 238000006722 reduction reaction Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 239000002356 single layer Substances 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 229910052938 sodium sulfate Inorganic materials 0.000 description 1
- 235000011152 sodium sulphate Nutrition 0.000 description 1
- 230000008961 swelling Effects 0.000 description 1
- 230000002195 synergetic effect Effects 0.000 description 1
- LRBQNJMCXXYXIU-NRMVVENXSA-N tannic acid Chemical compound OC1=C(O)C(O)=CC(C(=O)OC=2C(=C(O)C=C(C=2)C(=O)OC[C@@H]2[C@H]([C@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)[C@@H](OC(=O)C=3C=C(OC(=O)C=4C=C(O)C(O)=C(O)C=4)C(O)=C(O)C=3)O2)OC(=O)C=2C=C(OC(=O)C=3C=C(O)C(O)=C(O)C=3)C(O)=C(O)C=2)O)=C1 LRBQNJMCXXYXIU-NRMVVENXSA-N 0.000 description 1
- 229940033123 tannic acid Drugs 0.000 description 1
- 235000015523 tannic acid Nutrition 0.000 description 1
- 229920002258 tannic acid Polymers 0.000 description 1
- 229910052718 tin Inorganic materials 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 239000010936 titanium Substances 0.000 description 1
- YWYZEGXAUVWDED-UHFFFAOYSA-N triammonium citrate Chemical compound [NH4+].[NH4+].[NH4+].[O-]C(=O)CC(O)(CC([O-])=O)C([O-])=O YWYZEGXAUVWDED-UHFFFAOYSA-N 0.000 description 1
- WFKWXMTUELFFGS-UHFFFAOYSA-N tungsten Chemical compound [W] WFKWXMTUELFFGS-UHFFFAOYSA-N 0.000 description 1
- LEONUFNNVUYDNQ-UHFFFAOYSA-N vanadium atom Chemical compound [V] LEONUFNNVUYDNQ-UHFFFAOYSA-N 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- NWONKYPBYAMBJT-UHFFFAOYSA-L zinc sulfate Chemical compound [Zn+2].[O-]S([O-])(=O)=O NWONKYPBYAMBJT-UHFFFAOYSA-L 0.000 description 1
- 229910000368 zinc sulfate Inorganic materials 0.000 description 1
- 229960001763 zinc sulfate Drugs 0.000 description 1
Landscapes
- Electroplating Methods And Accessories (AREA)
Description
本発明は裸耐食性および塗装後の耐食性、溶接
性などの自動車用防錆鋼板に要求される諸性質に
優れた表面処理鋼板およびその製造方法に関する
ものである。
自動車用の防錆処理鋼板としてZnめつき鋼板
が使用されているが、純Zn層の腐食速度が速い
ため、特に苛酷な腐食環境、例えば寒冷地帯に散
布される岩塩などの道路凍結防止剤に露される場
合、Znめつき付着量をかなり多くしなければ
（一例をあげると、Zn付着量20〜40g／m2を60〜
120g／m2にする）、長期間の防錆が期待できなく
なりつつある。しかし、めつき付着量を多くする
ことはコストアツプはもとより、性能面でもめつ
き密着性、加工性、溶接性の劣化を生じるなどの
不利がある。
一方、Znめつき層の活性を抑制するため、電
位的にZnよりも貴な金属、例えばFe、Ni等をZn
と合金析出させてめつき層の腐食速度を小さく
し、薄めつき付着量（一例を挙げると、20〜
30g／m2）でも耐食性の優れたZn系合金めつき鋼
板の開発が行われ、車体の一部に採用されつつあ
る。
ここで、Zn−Fe系合金めつき鋼板は塗装前処
理としてのりん酸処理性が優れているため、塗装
後の耐食性が良い。しかし、その合金めつき層の
鋼板に対する保護防食効果が十分でないため、裸
耐食性は不十分である。また、Zn−Ni系合金め
つき鋼板はめつき層の腐食速度が著しく小さくな
るため、鋼板に対する保護防食効果が低下し、特
に加工後において鋼板からの赤錆発生が著しく、
その耐食性は必ずしも十分ではない。Zn−Ni系
合金めつき鋼板におけるこのような加工後の耐食
性劣化はめつき層中のNi含有量の増加により顕
著になる。その理由は、Ni含有量の増加につれ
て保護防食効果が低下し、加工時鋼板に達する亀
裂が多数生ずるためである。上述のように、これ
までのZnめつき鋼板またはZn系合金めつき鋼板
にはそれぞれ欠点があつた。
本発明者等は、上述のように単層めつきでは裸
耐食性および塗装後の耐食性、溶接性などの自動
車用防錆鋼板に要求される諸性質を全て向上させ
ることは極めて困難であるという認識に基づくと
ともに、所要のめつき厚さ全てに合金添加成分を
含有させることによる経済上、作業上の不利を除
くという立場に立脚し、研究を重ねた。その結
果、めつき層の腐食速度を著しく減少せしめ、か
つめつき層の合金化によつて生じ易くなる鋼板
（めつき原板）からの赤錆発生を減少せしめた耐
食性、溶接性などの自動車用防錆鋼板に要求され
る諸性能に優れためつき鋼板として、鋼板上に
ZnまたはZn系合金めつきを施し、その上に第２
層としてCo−ＷまたはCo−Cr合金めつきを施し
た積層めつき鋼板が所要の性能を満足するもので
あることを知見した。
Co−ＷまたはCo−Cr合金めつきをZnまたはZn
系合金めつき上に施したものは、腐食環境におい
て生成する腐食生成物のうち、腐食時のカソード
反応である酸素還元反応の抑制に効果のある水酸
化亜鉛Zn（OH）2が単相めつきに比べて、緻密で
しかも安定にめつき表面に形成されるためと考え
られ、冷熱サイクル腐食試験、複合腐食試験など
の腐食環境において極めて優れた耐食性を示し
た。
本発明はこのような知見に基づいてなされたも
ので、本発明の第１の態様によれば、鋼板上に、
第１層としてめつき付着量が3g／m2以上のZnま
たはZn系合金めつき層、第２層としてめつき付
着量が0.003〜3g／m2で、めつき皮膜のＷまたは
Cr含有量が0.01〜10wt％のCo−ＷまたはCo−Cr
合金めつき層を有する耐食性、溶接性等の優れた
積層めつき鋼板が提供される。本発明の第２の態
様によれば、鋼板に常法に従いZnまたはZn系合
金めつきを施し、次いでCo10〜100g／、Ｗま
たはCrを0.01〜10g／を含有するコバルトめつ
き浴中でCo−ＷまたはCo−Cr合金を電気めつき
する工程を有する高耐食性表面処理鋼板の製造方
法が提供される。
以下、本発明をさらに詳細に説明する。
表面清浄化処理等通常のめつき原板製造工程を
経て製造された鋼板に、まずZnまたはZn系合金
めつきを電気めつき法あるいは溶融めつき法によ
り予めめつきする。ここで、Znめつきとは電気
Znめつきおよび溶融Znめつきを包含し、Zz系合
金めつきとは合金化溶融Znめつき（Zn−Fe）、
Zn−Fe合金電気めつき、Zn−Ni合金電気めつ
き、Zn−Al複合電気めつきを包含するとともに、
Ni、Cr、Al、Mg、Mn、Fe、Ｗ、Ｖ、Sn、Mo、
In、Cu、Zr、Ti、Bi等を少なくとも１種総計で
0.1〜30wt％含有するZn系合金めつき（電気めつ
き法、溶融めつき法ともに含む）をも包含するも
のである。
この下層めつき層として使用される金属は上述
のように鋼板に対する保護防食効果の強いもの
（Znめつき）、あるいは保護防食効果を適度に抑
制したもの（Zn系合金めつき）が用いられる。
また、下層めつき層の厚さは耐食性、溶接性等か
ら３〜60g／m2の範囲が好ましい。下層めつき層
が3g／m2未満では鋼板（めつき原板）に対する
下層めつき層による均一被覆性が十分でなく、ま
た上層めつき層との重畳効果を加味しても満足す
べき赤錆発生防止効果が得られない。60g／m2を
超えるめつき付着量では、溶接性、加工性が劣化
するので好ましくない。
本発明は、上述のように鋼板にZnまたはZn系
合金めつきを施しためつき層の上に、さらにCo
−ＷまたはCo−Cr合金めつき層を形成せしめる
もので、そのめつき付着量は第１表および第２表
からもわかるように0.003〜3g／m2、好ましくは
0.01〜1g／m2であり、まためつき皮膜中のＷまた
はCr含有量は0.01〜10wt％、好ましくは0.05〜
5wt％である。そして、このCo−ＷまたはCo−
Cr合金めつき層は極めて少ない付着量で優れた
性能を発揮する。その効果と推定される理由は以
下の通りである。
(1) Co−ＷまたはCo−Cr合金めつき層は薄くポ
ーラスなため、下層のZnまたはZn系合金めつ
き層を完全に被覆していないと考えられ、従つ
て表面ではZnとCo−ＷまたはCo−Cr合金が細
かく均一に混在して分布している。このような
表面状態のものを塩水噴霧のごとき腐食環境に
さらした場合、ZnとCo−ＷまたはCo−Cr合金
との間に局部電池を形成し、露出している表面
のZnがアノードとなり溶出する。しかし、カ
ソードとなるCo−ＷまたはCo−Cr合金上で腐
食液中の溶存酸素の還元反応により生成した水
酸イオンOH-と直ちに反応して水酸化亜鉛Zn
（OH）2となり、表面に沈着する。このZn
（OH）2は緻密でしかも安定な上、ポーラスな
Co−ＷまたはCo−Cr合金めつき層により保持
されるため、下層のZnまたはZn系合金めつき
層の腐食が著しく抑制される。
(2) また、このCo−ＷまたはCo−Cr合金めつき
を施すことにより、りん酸塩処理性および塗装
後の性能、特に電着塗装後の耐食性を著しく向
上せしめる。すなわち、本発明の積層めつき製
品の主要な目的とする自動車用防錆鋼板は、一
般にりん酸処理および塗装を行つて使用される
分野が多いので、これらは優れた性能が要求さ
れる。本発明の表面処理鋼板は、りん酸塩処理
において均一緻密なりん酸塩結晶を得るに必要
なマイクロセルの形成に対して、上述の如く
ZnとCo−ＷまたはCo−Cr合金が細かく均一に
混在して分布しているため、そのりん酸塩処理
性が著しく向上する。
(3) さらに、このような上層めつき層の効果によ
る優れたりん酸塩処理性に加えて、塗装後の性
能、特に電着塗装後の耐食性向上効果が著し
い。すなわち、均一で緻密なりん酸塩結晶の生
成により、塗膜との密着性を向上せしめ、かつ
腐食環境において塗膜を通して浸入してくる腐
食溶液を均一緻密なりん酸塩結晶でめつき面に
到達するのを防止するため、塗装後の耐食性を
向上せしめる。さらに、めつき表面は極めて安
定なため、たとえば塗膜を通して腐食溶液がそ
の表面に到達しても、Co−ＷまたはCo−Cr合
金めつき皮膜と緻密で安定な腐食生成物（水酸
化亜鉛）皮膜によつて、電着塗膜にふくれ等の
欠陥が生じるのを防止し、その耐食性向上効果
が著しい。
(4) 一方、本発明による鋼板ではCo−Ｗまたは
Co−Cr合金めつき層が表面にあたるため、溶
接用Cuチツプと下層に存在するZnが合金をつ
くりにくくなるため、チツプ先端の形状変化を
防止し、連続溶接性が著しく向上する。さら
に、本発明による鋼板では耐食性が優れている
ため、下層のZnまたはZn系合金めつき層の付
着量を少なくすることが可能であることから
も、溶接性に有利である。
上述した効果と理由から、そして後に詳述する
結果を表わした第１表および第２表からわかるよ
うに、上層めつき層としてのCo−ＷまたはCo−
Cr合金めつき層の付着量は0.003g／m2〜3g／m2の
範囲にするのが良い。Co−ＷまたはCo−Cr合金
めつき層のめつき付着量が0.003g／m2未満では効
果が認められず、また3g／m2を超えると均一被
覆性が大幅に良くなるので耐食性向上効果が低下
し、またCo、Ｗともに高価なため経済的な面か
らも好ましくない。
次に、Co−ＷまたはCo−Cr合金めつき層に含
有されるＷまたはCrの効果についての理論的裏
づけは必ずしも明らかではないが、本発明者等の
実験結果から次のことが確認されている。すなわ
ち、Co中にＷまたはCrが合金あるいは共析状態
で含有された場合、特に加工後の耐食性が著しく
向上する。これは、加工時Co−ＷまたはCo−Cr
合金めつき層に入る亀裂が減少するためと考えら
れる。また、Co−ＷまたはCo−Cr合金めつきで
はCoとＷまたはCrの相乗効果により、均一で緻
密で安定なZn（OH）2の形成がより一層促進され
ることによるものと考えられる。
以上のことから、Co−ＷまたはCo−Cr合金め
つき層中のＷまたはCr含有量は0.01〜10wt％の
範囲が適正であることが判明した。その理由は、
ＷまたはCr含有量が0.01wt％未満では上述した
効果が認められず、一方10wt％を超えると効果
が飽和に達するとともに、めつき外観が悪くなる
ので好ましくないからである。
本発明の防錆鋼板は、鋼板にZnまたはZn系合
金めつきを施した後、引き続いて電気めつき法に
よりCo−ＷまたはCo−Cr合金めつきを行うこと
により製造される。Co−ＷまたはCo−Cr合金め
つき浴組成としては、金属Coとして10〜100g／
含有する水溶液のコバルト酸塩水溶液中に、水
溶性のタングステン酸塩またはクロム化合物を金
属ＷまたはCrとして0.01〜10g／含有するよう
添加調整し、適切なPHとしたものを用いる。使用
可能なコバルト酸塩としては、硫酸コバルト、塩
化コバルト、スルフアミン酸コバルト、ピロリン
酸コバルト（アルカリ性PH8.3）、クエン酸コバル
ト（酸性PH４、アルカリ性PH10）、ナフテン酸コ
バルトなどがあり、タングステン酸塩としては代
表的に、タングステン酸アンモニウム、タングス
テン酸ナトリウム、タングステン酸カリウム、タ
ングステン酸カルシウム、クロム化合物として
は、塩化クロム、硫酸クロム、無水クロム酸など
を挙げることができる。なお、Co−ＷまたはCo
−Cr合金めつき浴にはめつき操業安定化を図る
ため、塩化アンモニウム、硫酸ナトリウム等の電
気伝導助剤、ホウ酸、クエン酸アンモニウム等の
PH緩衝剤等を添加しても良い。Co−ＷまたはCo
−Cr合金めつきは電気めつき法でコーテイング
されるため付着量が少ない場合でも正確にコント
ロールすることができる。なお、Co−Ｗまたは
Co−Cr合金めつき皮膜中のＷまたはCr含有率は、
電流密度が大きい程、めつき浴温が比較的低い程
上がる傾向にあるから、必要に応じてＷまたは
Cr含有率をコントロールすることができる。ま
た、Co−ＷまたはCo−Crめつき層上にクロメー
トおよびタンニン酸系などの不溶性処理を実施す
ることによつて、より耐食性の向上が達成でき
る。
以下、本発明を実施例につき具体的に説明す
る。
実施例
冷延鋼板を常法に従い電解脱脂、酸洗した後、
以下の条件により各種の第１層のZnまたはZn系
合金めつきを行つた。
(A) 電気Znめつき
(1) 浴組成 塩化亜鉛 210g/
塩化カリウム 360g/
(2) 浴 温 55℃
(3) PH＝５
(4) 電流密度 30A／ｄm2
(5) めつき付着量 20g／m2
(B) Zn−Ni合金めつき
(1) 浴組成 塩化亜鉛 130g/
塩化ニツケル 240g/
塩化アンモニウム 60g/
(2) 浴 温 45℃
(3) PH＝４
(4) 電流密度 30A／ｄm2
(5) めつき付着量 20g／m2（Ni含有量13wt
％）
(C) Zn−Fe合金めつき
(1) 浴組成 塩化亜鉛 130g/
塩化第一鉄 120g/
塩化アンモニウム 60g/
クエン酸 ５g/
(2) 浴 温 50℃
(3) PH＝２
(4) 電流密度 30A／ｄm2
(5) めつき付着量 20g／m2（Fe含有量15wt
％）
(D) Zn−Al複合めつき
(1) 浴組成 硫酸亜鉛 0.5M/
水酸化亜鉛 0.5M/
水酸化アルミニウム 0.2M/
ホウ酸 30g/
アルミニウム粉末（−250mesh）
20〜30g/
(2) 浴 温 40℃
(3) PH＝５
(4) 電流密度 30A／ｄm2
(5) めつき付着量 20g／m2（Al含有量12wt
％）
(E) Zn−Cr合金めつき
(1) 浴組成 塩化亜鉛 130g/
塩化クロム 60g/
塩化アンモニウム 60g/
(2) 浴 温 50℃
(3) PH＝4.5
(4) 電流密度 30A／ｄm2
(5) めつき付着量 20g／m2（Cr含有量3wt％）
(F) 溶融Znめつき
一般のゼンジマー方式によつて溶融Znめつ
きを行つた。めつき付着量90g／m2
上述したようにして第１層のZnまたはZn系合
金めつきを行つた後、水洗して直に下記の条件で
第２層のCo−ＷまたはCo−Cr合金めつきを行つ
た。
(G) Co−Ｗ合金めつき
(1) 浴組成 硫酸コバルト 200g/
塩化アンモニウム 60g/
ホウ酸 30g/
タングステン酸ナトリウム 10
ｇ／
(2) 浴 温 40℃
(3) PH＝６
(4) 電流密度 １〜10A／ｄm2
(5) めつき付着量
電解電気量でコントロールし、Co−Ｗ合
金めつき層中のＷ含有量は約1wt％となるよ
うにコントロールした。
(H) Co−Cr合金めつき
(1) 浴組成 塩化コバルト 150g/
塩化アンモニウム 60g/
ホウ酸 30g/
塩化クロム 20g/
(2) 浴 温 40℃
(3) PH＝３
(4) 電流密度 １〜10A／ｄm2
(5) めつき付着量
電解電気量でコントロールし、Co−Ｗ合
金めつき層中のCr含有量は約1wt％となるよ
うにコントロールした。
このようにして得られた種々の積層めつき鋼板
について下記のような種々の性能試験を行つた。
その結果を第１表および第２表にまとめて示す。
第１表および第２表の試験結果から明らかなよう
に、Co−ＷまたはCo−Cr合金めつきの付着量は
0.003〜3g／m2とすることにより、そしてCo−Ｗ
またはCo−Cr合金めつき層中のＷまたはCr含有
量を0.01〜10wt％の範囲内に収めることにより、
特に自動車用防錆鋼板として要求される裸耐食
性、塗装後の耐食性、溶接性などの優れた鋼板が
得られる。
(1) 裸耐食性
Co−Ｗ合金は以下に示す冷熱サイクル腐食
試験（CCT）で行つた。また、Co−Cr合金は
以下に示す複合腐食試験に準拠して行つた。
(1‐1) 冷熱サイククル腐食試験
(a) 塩水噴霧試験（JIS Ｚ 2371）……４時
間
(b) 乾燥（60℃）……２時間
(c) 湿潤（60℃、相対湿度95％以上）……４
時間
(d) 冷凍（−15℃）……２時間
上記(a)〜(d)を１サイクルとして２サイク
ル／日で144および240時間行つた。
The present invention relates to a surface-treated steel sheet that is excellent in various properties required for a rust-proof steel sheet for automobiles, such as bare corrosion resistance, corrosion resistance after painting, and weldability, and a method for manufacturing the same. Zn-plated steel sheets are used as rust-prevention treated steel sheets for automobiles, but because the pure Zn layer corrodes at a high rate, they are not suitable for use in particularly harsh corrosive environments, such as road anti-icing agents such as rock salt sprayed in cold regions. If exposed, the amount of Zn plating must be considerably increased (for example, if the amount of Zn plating is 20 to 40g/ m2 ,
120g/ m2 ), it is becoming impossible to expect long-term rust prevention. However, increasing the amount of plating deposit not only increases costs but also has disadvantages in terms of performance, such as deterioration of plating adhesion, workability, and weldability. On the other hand, in order to suppress the activity of the Zn-plated layer, metals that are potentially more noble than Zn, such as Fe and Ni, are added to the Zn.
The corrosion rate of the plated layer is reduced by precipitating an alloy with
30g/m 2 ) has been developed and is being used in some car bodies. Here, since the Zn-Fe alloy plated steel sheet has excellent phosphoric acid treatment properties as a pre-painting treatment, it has good corrosion resistance after painting. However, since the alloy plating layer does not have a sufficient protective and anticorrosive effect on the steel plate, the bare corrosion resistance is insufficient. In addition, since the corrosion rate of the plated layer of Zn-Ni alloy plated steel sheets is significantly reduced, the protective and anticorrosive effect on the steel sheet is reduced, and the formation of red rust from the steel sheet is significant, especially after processing.
Its corrosion resistance is not necessarily sufficient. This deterioration in corrosion resistance of Zn-Ni alloy plated steel sheets after processing becomes more pronounced as the Ni content in the plated layer increases. The reason for this is that as the Ni content increases, the protective and anticorrosion effect decreases, and many cracks that reach the steel plate occur during processing. As mentioned above, conventional Zn-plated steel sheets and Zn-based alloy-plated steel sheets each have drawbacks. The present inventors recognize that, as mentioned above, it is extremely difficult to improve all the properties required for automotive rust-proof steel sheets, such as bare corrosion resistance, corrosion resistance after coating, and weldability, with single-layer plating. In addition to this, we conducted repeated research based on the standpoint of eliminating the economic and operational disadvantages caused by including alloying additives in all the required plating thicknesses. As a result, the corrosion rate of the plating layer has been significantly reduced, and the occurrence of red rust from the steel plate (plated original sheet), which is likely to occur due to alloying of the plating layer, has been reduced. As a matting steel plate with excellent performance required for rusted steel plates,
Zn or Zn-based alloy plating is applied, and a second
It has been found that a laminated plated steel plate coated with Co-W or Co-Cr alloy as a layer satisfies the required performance. Co-W or Co-Cr alloy plating with Zn or Zn
Among the corrosion products generated in a corrosive environment, the plating applied on the alloy plating contains a single phase of zinc hydroxide, Zn(OH) 2 , which is effective in suppressing the oxygen reduction reaction, which is a cathode reaction during corrosion. This is thought to be due to the fact that it is formed on the plated surface in a denser and more stable manner compared to the plated surface, and it showed extremely excellent corrosion resistance in corrosive environments such as cold/hot cycle corrosion tests and composite corrosion tests. The present invention has been made based on such knowledge, and according to the first aspect of the present invention, on a steel plate,
The first layer is a Zn or Zn-based alloy plating layer with a plating amount of 3 g/m 2 or more, and the second layer is a plating layer with a plating amount of 0.003 to 3 g/m 2 .
Co-W or Co-Cr with Cr content of 0.01~10wt%
A laminated plated steel plate having an alloy plated layer and having excellent corrosion resistance, weldability, etc. is provided. According to the second aspect of the present invention, a steel plate is plated with Zn or a Zn-based alloy according to a conventional method, and then coated with Co in a cobalt plating bath containing 10 to 100 g of Co and 0.01 to 10 g of W or Cr. A method for producing a highly corrosion-resistant surface-treated steel sheet is provided, which includes the step of electroplating -W or a Co-Cr alloy. The present invention will be explained in more detail below. First, Zn or Zn-based alloy plating is applied in advance to a steel plate manufactured through a normal plated original plate manufacturing process such as surface cleaning treatment by an electroplating method or a hot-dip plating method. Here, Zn plating means electric
Zn plating and fused Zn plating are included, and Zz alloy plating refers to alloyed fused Zn plating (Zn-Fe),
Including Zn-Fe alloy electroplating, Zn-Ni alloy electroplating, Zn-Al composite electroplating,
Ni, Cr, Al, Mg, Mn, Fe, W, V, Sn, Mo,
A total of at least one type of In, Cu, Zr, Ti, Bi, etc.
It also includes Zn-based alloy plating containing 0.1 to 30 wt% (including both electroplating method and hot-dip plating method). As mentioned above, the metal used for this lower plating layer is one that has a strong protective and anti-corrosion effect on steel sheets (Zn plating), or one that has a moderately suppressed protective and anti-corrosion effect (Zn-based alloy plating).
Further, the thickness of the lower plating layer is preferably in the range of 3 to 60 g/m 2 from the viewpoint of corrosion resistance, weldability, etc. If the lower plating layer is less than 3 g/m 2 , the uniform coverage of the lower plating layer on the steel plate (base plate) will not be sufficient, and even if the superimposed effect with the upper plating layer is taken into account, satisfactory red rust will occur. No preventive effect can be obtained. A plating weight exceeding 60 g/m 2 is undesirable because weldability and workability deteriorate. As described above, the present invention provides a method for applying Zn or Zn-based alloy plating to a steel plate, and then coating the plated layer with Co.
-W or Co-Cr alloy plating layer is formed, and as can be seen from Tables 1 and 2, the amount of plating is 0.003 to 3 g/m 2 , preferably
0.01~1g/ m2 , and the W or Cr content in the matte film is 0.01~10wt%, preferably 0.05~
It is 5wt%. And this Co-W or Co-
The Cr alloy plating layer exhibits excellent performance with an extremely small amount of adhesion. The reason for the presumed effect is as follows. (1) Since the Co-W or Co-Cr alloy plating layer is thin and porous, it is thought that it does not completely cover the underlying Zn or Zn-based alloy plating layer, and therefore the surface is composed of Zn and Co-W. Or the Co-Cr alloy is finely and uniformly mixed and distributed. When a product with such a surface condition is exposed to a corrosive environment such as salt spray, a local battery is formed between Zn and Co-W or Co-Cr alloy, and the exposed Zn on the surface becomes an anode and is eluted. do. However, on the Co-W or Co-Cr alloy that serves as the cathode, zinc hydroxide Zn immediately reacts with hydroxyl ions OH
(OH) 2 and deposits on the surface. This Zn
(OH) 2 is dense and stable, as well as porous.
Since it is held by the Co-W or Co-Cr alloy plating layer, corrosion of the underlying Zn or Zn-based alloy plating layer is significantly suppressed. (2) Furthermore, by applying this Co-W or Co-Cr alloy plating, phosphate treatment properties and performance after painting, especially corrosion resistance after electrodeposition painting, are significantly improved. That is, since rust-proof steel sheets for automobiles, which are the main object of the laminated plated product of the present invention, are generally used in many fields after being treated with phosphoric acid and painted, they are required to have excellent performance. The surface-treated steel sheet of the present invention is effective against the formation of microcells necessary to obtain uniformly dense phosphate crystals during phosphate treatment, as described above.
Since Zn and Co-W or Co-Cr alloy are finely and uniformly mixed and distributed, the phosphate treatability is significantly improved. (3) Furthermore, in addition to the excellent phosphate treatment properties due to the effect of the upper plating layer, the performance after coating, especially the corrosion resistance after electrodeposition coating, is significantly improved. In other words, the formation of uniform and dense phosphate crystals improves the adhesion with the paint film, and the uniform and dense phosphate crystals prevent corrosive solutions from penetrating through the paint film in a corrosive environment onto the plated surface. To prevent this from occurring, improve corrosion resistance after painting. Furthermore, because the plated surface is extremely stable, even if a corrosive solution reaches the surface through the coating, for example, a Co-W or Co-Cr alloy plated film and a dense and stable corrosion product (zinc hydroxide) will form. The film prevents defects such as blistering from occurring in the electrodeposition coating, and has a remarkable effect of improving corrosion resistance. (4) On the other hand, in the steel sheet according to the present invention, Co-W or
Since the Co-Cr alloy plating layer is on the surface, it becomes difficult for the Cu chip for welding and the Zn present in the underlying layer to form an alloy, which prevents the chip tip from changing shape and significantly improves continuous weldability. Furthermore, since the steel sheet according to the present invention has excellent corrosion resistance, it is possible to reduce the amount of the underlying Zn or Zn-based alloy plating layer, which is advantageous for weldability. For the above-mentioned effects and reasons, and as can be seen from Tables 1 and 2 showing the results detailed later, Co-W or Co-W as the upper plating layer.
The amount of the Cr alloy plating layer deposited is preferably in the range of 0.003g/m 2 to 3g/m 2 . If the plating weight of the Co-W or Co-Cr alloy plating layer is less than 0.003 g/ m2 , no effect will be observed, and if it exceeds 3 g/ m2 , the uniform coverage will be greatly improved, resulting in improved corrosion resistance. It is also unfavorable from an economical point of view because Co and W are both expensive. Next, although the theoretical basis for the effect of W or Cr contained in the Co-W or Co-Cr alloy plating layer is not necessarily clear, the following is confirmed from the experimental results of the present inventors. There is. That is, when W or Cr is contained in Co in an alloy or eutectoid state, the corrosion resistance especially after processing is significantly improved. This is Co-W or Co-Cr during processing.
This is thought to be due to fewer cracks entering the alloy plating layer. Furthermore, in Co-W or Co-Cr alloy plating, it is thought that the synergistic effect of Co and W or Cr further promotes the formation of uniform, dense, and stable Zn(OH) 2 . From the above, it has been found that the appropriate W or Cr content in the Co-W or Co-Cr alloy plating layer is in the range of 0.01 to 10 wt%. The reason is,
This is because if the W or Cr content is less than 0.01 wt%, the above-mentioned effects are not observed, whereas if it exceeds 10 wt%, the effect reaches saturation and the plating appearance deteriorates, which is not preferable. The rust-proof steel sheet of the present invention is manufactured by plating a steel sheet with Zn or a Zn-based alloy, and then subsequently plating with a Co-W or Co-Cr alloy using an electroplating method. The composition of the Co-W or Co-Cr alloy plating bath is 10 to 100 g/co of metal Co.
A water-soluble tungstate or chromium compound is added to the aqueous cobaltate solution containing 0.01 to 10 g of metal W or Cr, and the pH thereof is adjusted to an appropriate level. Usable cobalt salts include cobalt sulfate, cobalt chloride, cobalt sulfamate, cobalt pyrophosphate (alkaline PH8.3), cobalt citrate (acidic PH4, alkaline PH10), cobalt naphthenate, etc. Representative examples include ammonium tungstate, sodium tungstate, potassium tungstate, calcium tungstate, and chromium compounds include chromium chloride, chromium sulfate, and chromic anhydride. In addition, Co-W or Co
- In order to stabilize the plating operation in the Cr alloy plating bath, conductive additives such as ammonium chloride and sodium sulfate, boric acid, ammonium citrate, etc.
A PH buffer or the like may be added. Co-W or Co
- Since Cr alloy plating is applied by electroplating, it can be precisely controlled even when the amount of deposit is small. In addition, Co-W or
The W or Cr content in the Co-Cr alloy plating film is
The higher the current density and the lower the plating bath temperature, the higher the plating bath temperature.
Cr content can be controlled. Moreover, by performing insoluble treatment such as chromate and tannic acid on the Co-W or Co-Cr plating layer, corrosion resistance can be further improved. Hereinafter, the present invention will be specifically explained with reference to examples. Example After electrolytically degreasing and pickling a cold-rolled steel plate according to the conventional method,
Various types of first layer Zn or Zn-based alloy plating were performed under the following conditions. (A) Electric Zn plating (1) Bath composition Zinc chloride 210g/ Potassium chloride 360g/ (2) Bath temperature 55℃ (3) PH=5 (4) Current density 30A/dm 2 (5) Plating amount 20g /m 2 (B) Zn-Ni alloy plating (1) Bath composition Zinc chloride 130g/ Nickel chloride 240g/ Ammonium chloride 60g/ (2) Bath temperature 45℃ (3) PH=4 (4) Current density 30A/dm 2 (5) Plating amount 20g/m 2 (Ni content 13wt)
%) (C) Zn-Fe alloy plating (1) Bath composition Zinc chloride 130g/ Ferrous chloride 120g/ Ammonium chloride 60g/ Citric acid 5g/ (2) Bath temperature 50℃ (3) PH=2 (4) Current density 30A/dm 2 (5) Plating amount 20g/m 2 (Fe content 15wt
%) (D) Zn-Al composite plating (1) Bath composition Zinc sulfate 0.5M/ Zinc hydroxide 0.5M/ Aluminum hydroxide 0.2M/ Boric acid 30g/ Aluminum powder (-250mesh)
20～30g/ (2) Bath temperature 40℃ (3) PH=5 (4) Current density 30A/dm 2 (5) Plating amount 20g/m 2 (Al content 12wt
%) (E) Zn-Cr alloy plating (1) Bath composition Zinc chloride 130g/ Chromium chloride 60g/ Ammonium chloride 60g/ (2) Bath temperature 50℃ (3) PH=4.5 (4) Current density 30A/dm 2 (5) Plating amount: 20g/m 2 (Cr content: 3wt%) (F) Molten Zn plating Molten Zn plating was performed using the general Sendzimer method. Plating amount: 90 g/m 2 After plating the first layer of Zn or Zn-based alloy as described above, wash with water and immediately apply the second layer of Co-W or Co-Cr alloy under the following conditions. I went to meet someone. (G) Co-W alloy plating (1) Bath composition Cobalt sulfate 200g/ Ammonium chloride 60g/ Boric acid 30g/ Sodium tungstate 10
g/ (2) Bath temperature 40℃ (3) PH=6 (4) Current density 1 to 10A/dm 2 (5) Plating deposition amount Controlled by the amount of electrolytic electricity, W in the Co-W alloy plating layer was The content was controlled to be approximately 1wt%. (H) Co-Cr alloy plating (1) Bath composition Cobalt chloride 150g/ Ammonium chloride 60g/ Boric acid 30g/ Chromium chloride 20g/ (2) Bath temperature 40℃ (3) PH=3 (4) Current density 1~ 10 A/dm 2 (5) Plating deposition amount The amount of plating was controlled by the amount of electrolytic electricity, and the Cr content in the Co-W alloy plating layer was controlled to be approximately 1 wt%. Various performance tests as described below were conducted on the various laminated plated steel sheets thus obtained.
The results are summarized in Tables 1 and 2.
As is clear from the test results in Tables 1 and 2, the coating weight of Co-W or Co-Cr alloy plating is
By setting it as 0.003~3g/ m2 , and Co-W
Or by keeping the W or Cr content in the Co-Cr alloy plating layer within the range of 0.01 to 10 wt%,
In particular, a steel plate with excellent bare corrosion resistance, corrosion resistance after coating, weldability, etc. required as a rust-proof steel plate for automobiles can be obtained. (1) Bare corrosion resistance The Co-W alloy was subjected to the cold cycle corrosion test (CCT) shown below. In addition, the Co-Cr alloy was subjected to a composite corrosion test shown below. (1-1) Cold cycle corrosion test (a) Salt spray test (JIS Z 2371)...4 hours (b) Dry (60℃)...2 hours (c) Wet (60℃, relative humidity 95% or more) ...4
Time (d) Freezing (-15°C)...2 hours The above (a) to (d) were treated as one cycle, and 2 cycles/day were carried out for 144 and 240 hours.
【表】
(1‐2) 複合腐食試験
(a) 塩水噴霧試験（JIS Ｚ 2371）……４時
間
(b) 熱風乾燥（60℃）……１時間
(c) 湿潤試験（50℃、相対温度70％以上）…
…３時間
上記(a)〜(c)を１サイクルとして４サイク
ル／日で168および240時間行つた。[Table] (1-2) Combined corrosion test (a) Salt spray test (JIS Z 2371)...4 hours (b) Hot air drying (60℃)...1 hour (c) Humidity test (50℃, relative temperature over 70)…
...3 hours The above (a) to (c) were carried out in 4 cycles/day for 168 and 240 hours.
【表】
(2) りん酸塩処理性
ボンデライト＃3128（日本パーカライジング
(株)製）を50℃で140秒間スプレー処理し、均一
で緻密で微細な結晶ができる付着量により評価
した。なお、×評価では不均一でポーラスで粗
大な結晶となつた。[Table] (2) Phosphate treatment Bonderite #3128 (Nippon Parkerizing
Co., Ltd.) was sprayed at 50°C for 140 seconds, and evaluation was made based on the amount of adhered particles that produced uniform, dense, and fine crystals. In addition, in the case of x evaluation, the crystals were non-uniform, porous, and coarse.
【表】
(3) 電着塗装後の耐食性
ボンデライト＃3128でりん酸塩処理後、パワ
ートツプＵ−30ブラツク（日本ペイント(株)製）
を用いて20μmのカチオン電着塗装を行い、上
述した冷熱サイクル腐食試験および複合腐食試
験に準拠してクロスカツト部からの塗膜ふくれ
幅により評価した。[Table] (3) Corrosion resistance after electrodeposition coating After phosphate treatment with Bonderite #3128, Power Top U-30 Black (manufactured by Nippon Paint Co., Ltd.)
A cationic electrodeposition coating of 20 μm was performed using a cationic electrodeposition coating, and the coating was evaluated based on the width of the coating film swelling from the cross-cut area in accordance with the above-mentioned cold/heat cycle corrosion test and composite corrosion test.
【表】
(4) 溶接性
肉厚0.7mmの片面めつき鋼板を用い、めつき
面を外側にして重ね合わせてスポツト溶接を行
い、連続溶接可能打点数で評価した。[Table] (4) Weldability Using single-sided plated steel plates with a wall thickness of 0.7 mm, spot welding was performed by overlapping the plates with the plated side facing outward, and evaluation was performed based on the number of continuous welding points.
【表】
本発明は上述の分野に限られず、下記のような
種々の分野に適用することができる。
(1) 本発明の積層めつきはジンクリツチプライマ
ー（Zn粉末等の金属粉を含む導電性有機コー
テイング）の下地としても好適であり、極めて
優れた耐食性を発揮する。
(2) 本発明の積層めつきは鋼板の片面あるいは両
面に適用でき、両面めつきの場合用途に応じて
差厚めつき、異種めつきを行うことができる。
(3) 本発明のCo−ＷまたはCo−Cr合金めつきに
おいて、ＷまたはCrの代りにバナジウム、チ
タン、モリブデン、ジルコニウム等の金属を用
いても同様の効果を奏する。[Table] The present invention is not limited to the above-mentioned fields, but can be applied to various fields as described below. (1) The laminated plating of the present invention is also suitable as a base for a zinc-rich primer (a conductive organic coating containing metal powder such as Zn powder), and exhibits extremely excellent corrosion resistance. (2) The laminated plating of the present invention can be applied to one or both sides of a steel plate, and in the case of double-sided plating, differential thickness plating or different types of plating can be performed depending on the application. (3) In the Co-W or Co-Cr alloy plating of the present invention, similar effects can be obtained even if metals such as vanadium, titanium, molybdenum, and zirconium are used instead of W or Cr.
【表】【table】
【表】【table】
【表】【table】
【表】【table】
Claims (1)
3g／m2以上のZnまたはZn系合金めつき層および
第２層としてめつき付着量が0.003〜3g／m2で、
めつき皮膜のＷまたはCr含有量が0.01〜10wt％
のCo−ＷまたはCo−Cr合金めつき層を形成して
なることを特徴とする高耐食性表面処理鋼板。 ２ 鋼板にZnまたはZn系合金めつきを施し、次
いでCoを10〜100g／、ＷまたはCrを0.01〜
10g／含有するコバルトめつき浴中でCo−Ｗま
たはCo−Cr合金を電気めつきすることを特徴と
する高耐食性表面処理鋼板の製造方法。[Claims] 1. On a steel plate, the amount of plating deposited as the first layer is
Zn or Zn-based alloy plating layer of 3 g/m 2 or more and a plating amount of 0.003 to 3 g/m 2 as the second layer,
W or Cr content of plating film is 0.01~10wt%
A highly corrosion-resistant surface-treated steel sheet, characterized by forming a Co-W or Co-Cr alloy plating layer. 2. Apply Zn or Zn-based alloy plating to a steel plate, then add 10 to 100 g of Co and 0.01 to 0.01 g of W or Cr.
A method for producing a highly corrosion-resistant surface-treated steel sheet, which comprises electroplating Co-W or Co-Cr alloy in a cobalt plating bath containing 10 g/cobalt.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13609982A JPS5925992A (en) | 1982-08-04 | 1982-08-04 | Surface treated steel sheet having high corrosion resistance and its production |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP13609982A JPS5925992A (en) | 1982-08-04 | 1982-08-04 | Surface treated steel sheet having high corrosion resistance and its production |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5925992A JPS5925992A (en) | 1984-02-10 |
| JPH0210236B2 true JPH0210236B2 (en) | 1990-03-07 |
Family
ID=15167242
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP13609982A Granted JPS5925992A (en) | 1982-08-04 | 1982-08-04 | Surface treated steel sheet having high corrosion resistance and its production |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5925992A (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| LU85453A1 (en) * | 1984-07-06 | 1986-02-12 | Cockerill Sambre Sa | HOT GALVANIZED STEEL PRODUCT, IN PARTICULAR FOR USE AS A PHOSPHATE, AND PROCESS FOR PREPARING THE SAME |
| US4663245A (en) * | 1985-05-16 | 1987-05-05 | Nippon Steel Corporation | Hot-dipped galvanized steel sheet having excellent black tarnish resistance and process for producing the same |
| JPS6228698U (en) * | 1985-08-07 | 1987-02-21 | ||
| JPH0689473B2 (en) * | 1990-04-25 | 1994-11-09 | 新日本製鐵株式会社 | Anti-corrosion steel plate with excellent corrosion resistance |
| KR100455083B1 (en) * | 2000-12-22 | 2004-11-08 | 주식회사 포스코 | Zn-Co-W alloy electroplated steel sheet with excellent corrosion resistance and welding property and electrolyte therefor |
| KR100854505B1 (en) | 2007-02-23 | 2008-08-26 | (주)해빛정보 | Plating layer and plating method using tungsten cobalt and tin cobalt |
-
1982
- 1982-08-04 JP JP13609982A patent/JPS5925992A/en active Granted
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5925992A (en) | 1984-02-10 |
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