JPS626758B2 - - Google Patents
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- Publication number
- JPS626758B2 JPS626758B2 JP23245983A JP23245983A JPS626758B2 JP S626758 B2 JPS626758 B2 JP S626758B2 JP 23245983 A JP23245983 A JP 23245983A JP 23245983 A JP23245983 A JP 23245983A JP S626758 B2 JPS626758 B2 JP S626758B2
- Authority
- JP
- Japan
- Prior art keywords
- alumina sol
- plating
- chloride
- plating layer
- corrosion
- 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 32
- 230000007797 corrosion Effects 0.000 claims description 28
- 238000005260 corrosion Methods 0.000 claims description 28
- PNEYBMLMFCGWSK-UHFFFAOYSA-N aluminium oxide Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 claims description 27
- 229910000831 Steel Inorganic materials 0.000 claims description 17
- 239000010959 steel Substances 0.000 claims description 17
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 15
- 239000002131 composite material Substances 0.000 claims description 9
- 229910052742 iron Inorganic materials 0.000 claims description 8
- 229910018072 Al 2 O 3 Inorganic materials 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 229910052759 nickel Inorganic materials 0.000 claims description 6
- 239000011701 zinc Substances 0.000 description 29
- XEEYBQQBJWHFJM-UHFFFAOYSA-N Iron Chemical compound [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 description 14
- JIAARYAFYJHUJI-UHFFFAOYSA-L zinc dichloride Chemical compound [Cl-].[Cl-].[Zn+2] JIAARYAFYJHUJI-UHFFFAOYSA-L 0.000 description 11
- WCUXLLCKKVVCTQ-UHFFFAOYSA-M Potassium chloride Chemical compound [Cl-].[K+] WCUXLLCKKVVCTQ-UHFFFAOYSA-M 0.000 description 8
- 230000000694 effects Effects 0.000 description 8
- 239000000203 mixture Substances 0.000 description 6
- 238000006243 chemical reaction Methods 0.000 description 5
- 239000011651 chromium Substances 0.000 description 5
- 239000011248 coating agent Substances 0.000 description 5
- 238000000576 coating method Methods 0.000 description 5
- 150000001875 compounds Chemical class 0.000 description 5
- PXHVJJICTQNCMI-UHFFFAOYSA-N nickel Substances [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 5
- 239000000047 product Substances 0.000 description 5
- 235000005074 zinc chloride Nutrition 0.000 description 5
- 239000011592 zinc chloride Substances 0.000 description 5
- NLXLAEXVIDQMFP-UHFFFAOYSA-N Ammonia chloride Chemical compound [NH4+].[Cl-] NLXLAEXVIDQMFP-UHFFFAOYSA-N 0.000 description 4
- 230000007423 decrease Effects 0.000 description 4
- 238000011156 evaluation Methods 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- 239000003973 paint Substances 0.000 description 4
- 239000002245 particle Substances 0.000 description 4
- 239000001103 potassium chloride Substances 0.000 description 4
- 235000011164 potassium chloride Nutrition 0.000 description 4
- 101100203596 Caenorhabditis elegans sol-1 gene Proteins 0.000 description 3
- VEXZGXHMUGYJMC-UHFFFAOYSA-M Chloride anion Chemical compound [Cl-] VEXZGXHMUGYJMC-UHFFFAOYSA-M 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 150000002500 ions Chemical class 0.000 description 3
- 229910052751 metal Inorganic materials 0.000 description 3
- 239000002184 metal Substances 0.000 description 3
- 238000000034 method Methods 0.000 description 3
- 150000003839 salts Chemical class 0.000 description 3
- 239000000243 solution Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- 229910021555 Chromium Chloride Inorganic materials 0.000 description 2
- 229910021586 Nickel(II) chloride Inorganic materials 0.000 description 2
- 229910019142 PO4 Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 235000019270 ammonium chloride Nutrition 0.000 description 2
- 125000002091 cationic group Chemical group 0.000 description 2
- QSWDMMVNRMROPK-UHFFFAOYSA-K chromium(3+) trichloride Chemical compound [Cl-].[Cl-].[Cl-].[Cr+3] QSWDMMVNRMROPK-UHFFFAOYSA-K 0.000 description 2
- GVPFVAHMJGGAJG-UHFFFAOYSA-L cobalt dichloride Chemical compound [Cl-].[Cl-].[Co+2] GVPFVAHMJGGAJG-UHFFFAOYSA-L 0.000 description 2
- 238000004090 dissolution Methods 0.000 description 2
- 238000004070 electrodeposition Methods 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- QMMRZOWCJAIUJA-UHFFFAOYSA-L nickel dichloride Chemical compound Cl[Ni]Cl QMMRZOWCJAIUJA-UHFFFAOYSA-L 0.000 description 2
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 2
- 239000010452 phosphate Substances 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- 229910017090 AlO 2 Inorganic materials 0.000 description 1
- KRHYYFGTRYWZRS-UHFFFAOYSA-M Fluoride anion Chemical compound [F-] KRHYYFGTRYWZRS-UHFFFAOYSA-M 0.000 description 1
- GRYLNZFGIOXLOG-UHFFFAOYSA-N Nitric acid Chemical compound O[N+]([O-])=O GRYLNZFGIOXLOG-UHFFFAOYSA-N 0.000 description 1
- FAPWRFPIFSIZLT-UHFFFAOYSA-M Sodium chloride Chemical compound [Na+].[Cl-] FAPWRFPIFSIZLT-UHFFFAOYSA-M 0.000 description 1
- QAOWNCQODCNURD-UHFFFAOYSA-L Sulfate Chemical compound [O-]S([O-])(=O)=O QAOWNCQODCNURD-UHFFFAOYSA-L 0.000 description 1
- 229910007570 Zn-Al Inorganic materials 0.000 description 1
- 239000002253 acid Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 150000007513 acids Chemical class 0.000 description 1
- 239000012670 alkaline solution Substances 0.000 description 1
- -1 aluminate ion Chemical class 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 229910001593 boehmite Inorganic materials 0.000 description 1
- 239000004566 building material Substances 0.000 description 1
- 239000010960 cold rolled steel Substances 0.000 description 1
- 239000000084 colloidal system Substances 0.000 description 1
- 239000013078 crystal Substances 0.000 description 1
- 230000007547 defect Effects 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000006866 deterioration Effects 0.000 description 1
- XPPKVPWEQAFLFU-UHFFFAOYSA-J diphosphate(4-) Chemical compound [O-]P([O-])(=O)OP([O-])([O-])=O XPPKVPWEQAFLFU-UHFFFAOYSA-J 0.000 description 1
- 235000011180 diphosphates Nutrition 0.000 description 1
- 239000002612 dispersion medium Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 229960002089 ferrous chloride Drugs 0.000 description 1
- 230000005484 gravity Effects 0.000 description 1
- 230000007062 hydrolysis Effects 0.000 description 1
- 238000006460 hydrolysis reaction Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- FAHBNUUHRFUEAI-UHFFFAOYSA-M hydroxidooxidoaluminium Chemical compound O[Al]=O FAHBNUUHRFUEAI-UHFFFAOYSA-M 0.000 description 1
- 238000009863 impact test Methods 0.000 description 1
- NMCUIPGRVMDVDB-UHFFFAOYSA-L iron dichloride Chemical compound Cl[Fe]Cl NMCUIPGRVMDVDB-UHFFFAOYSA-L 0.000 description 1
- 238000003754 machining Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- LNOPIUAQISRISI-UHFFFAOYSA-N n'-hydroxy-2-propan-2-ylsulfonylethanimidamide Chemical compound CC(C)S(=O)(=O)CC(N)=NO LNOPIUAQISRISI-UHFFFAOYSA-N 0.000 description 1
- 229910017604 nitric acid Inorganic materials 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 238000010422 painting Methods 0.000 description 1
- 239000012466 permeate Substances 0.000 description 1
- 238000005554 pickling Methods 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 238000013441 quality evaluation Methods 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 239000011780 sodium chloride Substances 0.000 description 1
- 239000003381 stabilizer Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
Landscapes
- Electroplating Methods And Accessories (AREA)
Description
本発明は、裸耐食性、塗装後耐食性および溶接
性などの諸性質に優れた電気Zn−アルミナ系複
合めつき鋼板に関するものである。
Znめつき鋼板は、耐食性が要求される自動
車、家電製品、建築材料などに防錆処理鋼板とし
て広く使用されている。これは、純Zn層が鋼板
の鉄に対して卑であるので、ピンホールなどのめ
つき欠陥や加工により生じた地鉄の露出部分に対
してはZnが先に腐食されるという犠牲防食効果
があり、鋼板の赤錆発生を防止するからである。
しかし、純Znは活性なため塩水噴霧等の腐食環
境において、Znめつき層自体の腐食が著しく進
行する欠点がある。また、純Znは腐食生成物と
して導電性のZnOを生成しやすいため、表面に存
在する腐食生成物による保護効果が乏しいことも
耐食性が十分でない一因と考えられる。
本発明者等は、このようなZnめつき層の活性
を抑制し、さらに導電性の腐食生成物ZnOの生成
を抑制させるものとして、特公昭54−30649号、
川崎製鉄技報vol.12、No.4、P625（1980）で、Zn
−Al複合電気めつき鋼板を提案している。この
Zn−Al複合電気めつき層は電気Znめつき層中に
金属Al粒子を分散含有せしめたもので、特に裸
耐食性が優れている。しかし、めつき密着性を向
上させるため、めつき後に圧下率２％程度の圧延
を施した場合、素地鋼板の加工劣化をもたらし、
またりん酸塩処理後、カチオン電着塗装等の塗装
を施した場合、腐食条件によつては塗膜ふくれを
生じやすい欠点があつた。
この塗膜ふくれの原因としては、塗膜を透過し
た水と酸素がめつき表面のカソード部で還元さ
れ、次式により
H2O＋1/2O2＋2e→2OH-
水酸イオンを生ずるため、塗膜下が強アルカリ
性となり、両性金属であるAlおよびZnが溶解す
る。とくにめつき層中Alが存在する場合、Alは
アルカリ溶液中ではアルミン酸イオンとなり、次
式により
Al＋3OH-→AlO2 -＋H+＋H2O
速やかに溶解するため、塗膜ふくれの原因になる
と推測されている。
従つて、本発明は裸耐食性、塗装後耐食性、溶
接性などの諸性質に優れた電気Zn−アルミナ系
複合めつき鋼板を提供しようとするにある。
本発明の第１の態様によれば、電気Znめつき
層中に濃度0.1N以上の塩酸に可溶なアルミナゾ
ルをAl2O3換算で0.01〜3wt％含有することを特
徴とする高耐食性Zn−アルミナ系複合電気めつ
き鋼板が提供される。
本発明の第２の態様によれば、電気Znめつき
層中に、Co、Ni、FeおよびCrより成る群から選
択された少なくとも１種の元素を0.1〜30wt％含
有し、さらに濃度0.1N以上の塩酸に可溶なアル
ミナゾルをAl2O3換算で0.01〜3wt％含有するこ
とを特徴とする高耐食性Zn−アルミナ系複合電
気めつき鋼板が提供される。
本発明は以下に述べる知見に基いてなされたも
のである。
(1) Znめつき層中にAlを含有すると耐食性が向
上する。これはめつき層のZnとAlが腐食する
過程でAlイオンが生成し、保護効果の優れた
腐食生成物Zn（OH）2の生成と安定性に寄与す
る。
(2) Znめつき層中に酸に可溶なAl化合物を含有
させることにより、腐食生成物中にAlイオン
を存在させることができる。すなわち、腐食は
アノード反応とカソード反応で進行するが、ア
ノード部では次式により
Zn→Zn2+＋2e
Zn2+＋2H2O→Zn（OH）2＋2H+
Fe→Fe2+＋2e
Fe2+＋2H2O→Fe（OH）2＋2H+
ZnおよびまたはFe（素地鋼）の溶解と加水
分解によつて酸性化し、めつき層中に存をする
Al化合物を溶解（Alのイオン化）する。一
方、カソード部では金属Alげ存在しないた
め、Alの溶解反応が生じないので、塗膜ふく
れの原因となるカソード反応が抑制される。
(3) 腐食環境によつては、Znより貴なCo、Ni、
Fe、Crの元素の１種または２種以上をZnめつ
き層中に含有させることにより、Znめつき層
の活性を抑制する。さらに、Al化合物をめつ
き層中に含有させると、より一層耐食性に優れ
る効果がある。
以下に本発明を更に詳細に説明する。
Znめつき液に添加するAl化合物としては、正
に帯電しているアルミナゾルが望ましい。正帯電
によつてめつき層中に共析しやすくなるためであ
る。また、一般にアルミナゾルは100℃以下の低
温で湿式法によつて製造されるため、完全に
Al2O3になつておらず、大部分はAlの水酸化物あ
るいは水和酸化物あるいはまたAl塩との複合物
として存在している。このようなアルミナゾルが
めつき層に共析した場合、0.1Nより強い酸には
比較的容易に溶解する。とくに塩酸には溶解しや
すい。なお、食塩水を主体とする腐食液における
アノード部ではHClが生成するため、PHが低下
し、酸性となる。したがつて、本発明で用いる
Al化合物としては0.1N以上の塩酸に可溶なアル
ミナゾルとするのが好適である。
Znめつき層中のアルミナゾルの含有量はAl2O3
換算で0.01〜3wt％が望ましい。これが0.01wt％
未満では耐食性向上効果が十分でなく、また3wt
％をこえるとめつき外観が黒変し、めつき密着性
がやや低下する傾向がみられるだけでなく、めつ
き浴中に高濃度のアルミナゾル添加を必要とし、
浴粘性は増大して製造上にも問題を生ずる。
Znめつき層の活性をより一層抑制する合金元
素としては、Znより貴なCo、Ni、Fe、Crが選定
される。これら合金元素の１種または２種以上の
めつき層中含有率は0.1〜30wt％が望ましい。め
つき層中でアルミナゾルと共存させても、0.1wt
％未満では十分な耐食性向上効果を発揮しない。
また、30wt％をこえるとZnの犠牲防食性能が低
下するため、腐食環境によつては耐食性低下をも
たらし、またコストも大幅に増加するので望まし
くない。
以下本発明を実施例および比較例を上げて具体
的に説明する。
冷延鋼板（SPCC）をアルカリ電解脱脂し、５
％塩酸で酸洗したのち、水洗し、以下の条件によ
りめつきを行つた。撹拌はポンプにより行い、液
流速は約60ｍ／minで、陽極に純Zn板を使用し、
極間距離は20mm、液温は50℃で行つた。目付量は
全て20ｇ／m2とした。
Znめつき液に添加するアルミナゾルは日産化
学(株)製の＃520を用いた。その性状は次の通りで
ある。このアルミナゾルは0.1N以上の塩酸によ
く溶解する。
Al2O3含有量：20wt％
分散媒：水
PH：4.5
比重：1.23（25℃）
粘度：8C.P（20℃）
表面積：245m2／ｇ
安定剤：硝酸
粒子形状：棒〜粒状
粒子電荷：陽性
結晶形：凝ベーマイト
粒子の大きさ：５〜20ｍμ
外観：乳白色膠質液
なお、Znめつき浴は硫酸塩浴、塩化物浴、ピ
ロリン酸浴、スルフアミン酸浴、フツ化物浴、ホ
ウフツ化物浴あるいは、これらの混合浴を用いる
ことができる。以下の例では塩化物浴を主体に示
すが、これにのみ限定されない。ここで、めつき
層中に含有するアルミナゾルの量およびCo、
Ni、Fe、Crの総量はめつき液中の添加濃度によ
り適宜コントロールした。
実施例 １
浴組成 塩化亜鉛 200ｇ／
塩化カリウム 350ｇ／
アルミナゾル １〜100ml／
PH4.5、電流密度 75A／ｄm2
実施例 ２
浴組成 塩化亜鉛 200ｇ／
塩化カリウム 300ｇ／
塩化コバルト 0.1〜100ｇ／
アルミナゾル １〜100ml／
PH2.5、電流密度 100A／ｄm2
実施例 ３
浴組成 塩化亜鉛 200ｇ／
塩化カリウム 300ｇ／
塩化ニツケル 0.1〜100ｇ／
アルミナゾル １〜100ml／
PH３、電流密度 75A／ｄm2
実施例 ４
浴組成 塩化亜鉛 200ｇ／
塩化アンモニウム 300ｇ／
塩化第一鉄 0.1〜100ｇ／
アルミナゾル １〜100ml／
PH２、電流密度 150A／ｄm2
実施例 ５
浴組成 塩化亜鉛 200ｇ／
塩化アンモニウム 300ｇ／
塩化クロム 0.1〜100ｇ／
アルミナゾル １〜100ml／
PH２、電流密度 75A／ｄm2
実施例 ６
浴組成 塩化亜鉛 150ｇ／
塩化カリウム 300ｇ／
アルミナゾル １〜100ml／
を基本浴として、これに
塩化コバルト 0.1〜50ｇ／
塩化ニツケル 0.1〜50ｇ／
塩化第一鉄 0.1〜50ｇ／
塩化クロム 0.1〜50ｇ／
の２種以上を適宜添加して、電流密度100A／ｄ
m2でめつきを行つた。
比較例
比較のために、アルミナゾルの添加濃度、
Co、Ni、Fe、Crの１種または２種以上のイオン
の添加濃度を上記実施例の範囲外として、品質評
価試験用のめつき鋼板を作成した。
上記実施例および比較例で得たれためつき鋼板
につき以下に述べる試験を行つた。その結果を第
１表に示す。
(1) めつき密着性評価方法
デユポン衝撃試験（撃心径 1/2インチ、重
さ１Kg、高さ 50cm）後のめつき層の剥離状態
で評価した。
◎……剥離なし
〇……極くわずか剥離
△……わずかに剥離
×……剥離多し
(2) 耐食性評価方法
りん酸塩処理（日本パーカライジング(株) ボ
ンデライト＃3004）を行つたのち、カチオン電
着塗装（日本ペイント(株) パワートツプＵ−
30）を10μｍ施した試料について、素地鋼板に
たつするまでのクロスカツトを入れ、次のサイ
クル腐食試験を、塩水噴霧（JIS Z2371）10時
間、乾燥（60℃）２時間、湿潤（50℃、95％相
対湿度）６時間、乾燥（室温）６時間を１サイ
クルとして第１表末尾に示す数のサイクル行
い、クロスカツト部のふくれ幅で評価した。
◎……０〜１mm
〇……１〜３mm
△……３〜６mm
×……６mm以上
The present invention relates to an electric Zn-alumina composite plated steel sheet that has excellent properties such as bare corrosion resistance, post-painting corrosion resistance, and weldability. Zn-plated steel sheets are widely used as anti-rust steel sheets in automobiles, home appliances, building materials, etc. that require corrosion resistance. This is because the pure Zn layer is base against the iron of the steel sheet, so it has a sacrificial corrosion protection effect where the Zn corrodes first against plating defects such as pinholes and exposed areas of the base steel caused by machining. This is because it prevents red rust from forming on the steel plate.
However, since pure Zn is active, it has the disadvantage that corrosion of the Zn plating layer itself progresses significantly in corrosive environments such as salt spray. In addition, since pure Zn tends to produce conductive ZnO as a corrosion product, it is thought that one reason for the insufficient corrosion resistance is that the protection effect of the corrosion products existing on the surface is poor. The present inventors have proposed a method for suppressing the activity of such a Zn-plated layer and further suppressing the formation of conductive corrosion product ZnO, as described in Japanese Patent Publication No. 54-30649,
In Kawasaki Steel Technical Report vol.12, No.4, P625 (1980), Zn
-We are proposing an Al composite electroplated steel sheet. this
The Zn-Al composite electroplated layer has metal Al particles dispersed in the electroplated Zn layer, and has particularly excellent bare corrosion resistance. However, if rolling is performed at a reduction rate of about 2% after plating to improve plating adhesion, processing deterioration of the base steel sheet will occur.
Furthermore, when a coating such as cationic electrodeposition coating is applied after phosphate treatment, there is a drawback that the coating film tends to blister depending on the corrosion conditions. The cause of this paint film blistering is that the water and oxygen that permeate through the paint film are reduced at the cathode part of the plating surface, producing H 2 O + 1/2O 2 + 2e→2OH - hydroxyl ions according to the following formula. becomes strongly alkaline, and the amphoteric metals Al and Zn dissolve. In particular, when Al is present in the plating layer, Al becomes an aluminate ion in an alkaline solution, and according to the following formula, Al + 3OH - → AlO 2 - +H + +H 2 O It is assumed that this will cause paint film blistering because it will dissolve quickly. has been done. Accordingly, the present invention aims to provide an electrolytic Zn-alumina composite plated steel sheet that has excellent properties such as bare corrosion resistance, post-coating corrosion resistance, and weldability. According to the first aspect of the present invention, the highly corrosion-resistant Zn is characterized in that the electrolytic Zn plating layer contains 0.01 to 3 wt% of alumina sol soluble in hydrochloric acid with a concentration of 0.1 N or more in terms of Al 2 O 3 . - An alumina-based composite electroplated steel sheet is provided. According to the second aspect of the present invention, the electroplated Zn layer contains 0.1 to 30 wt% of at least one element selected from the group consisting of Co, Ni, Fe, and Cr, and further contains a concentration of 0.1N. A highly corrosion-resistant Zn-alumina composite electroplated steel sheet is provided, which is characterized by containing the above hydrochloric acid-soluble alumina sol in an amount of 0.01 to 3 wt% in terms of Al 2 O 3 . The present invention has been made based on the findings described below. (1) Including Al in the Zn plating layer improves corrosion resistance. This is because Al ions are generated during the process of corrosion of Zn and Al in the plating layer, contributing to the generation and stability of Zn(OH) 2 , a corrosion product with excellent protective effects. (2) By including an acid-soluble Al compound in the Zn plating layer, Al ions can be present in the corrosion product. In other words, corrosion progresses through an anode reaction and a cathode reaction, but in the anode part, Zn→Zn 2+ +2e Zn 2+ +2H 2 O→Zn(OH) 2 +2H + Fe→Fe 2+ +2e Fe 2+ +2H 2 O→Fe(OH) 2 +2H + Acidified by dissolution and hydrolysis of Zn and/or Fe (base steel) and exists in the plating layer
Dissolves Al compounds (ionizes Al). On the other hand, since there is no metal Al in the cathode portion, no dissolution reaction of Al occurs, and therefore the cathode reaction that causes paint film blistering is suppressed. (3) Depending on the corrosive environment, Co, Ni, and
By containing one or more of the elements Fe and Cr in the Zn plating layer, the activity of the Zn plating layer is suppressed. Furthermore, when an Al compound is contained in the plating layer, it has the effect of further improving corrosion resistance. The present invention will be explained in more detail below. As the Al compound added to the Zn plating solution, positively charged alumina sol is desirable. This is because positive charging makes it easier to eutectoid in the plating layer. In addition, since alumina sol is generally produced by a wet method at a low temperature of 100°C or less, it is completely
It is not converted into Al 2 O 3 , and most of it exists as Al hydroxide or hydrated oxide, or as a composite with Al salt. When such alumina sol is eutectoid on the plating layer, it is relatively easily dissolved in acids stronger than 0.1N. It is particularly soluble in hydrochloric acid. In addition, HCl is generated in the anode part of the corrosive liquid mainly composed of saline, so the pH decreases and becomes acidic. Therefore, used in the present invention
As the Al compound, it is preferable to use an alumina sol that is soluble in 0.1N or higher hydrochloric acid. The content of alumina sol in the Zn plating layer is Al 2 O 3
A conversion of 0.01 to 3wt% is desirable. This is 0.01wt%
If it is less than 3wt, the corrosion resistance improvement effect will not be sufficient, and
%, the plating appearance tends to turn black and the plating adhesion tends to decrease slightly, and it is necessary to add a high concentration of alumina sol to the plating bath.
The viscosity of the bath increases, creating manufacturing problems. Co, Ni, Fe, and Cr, which are more noble than Zn, are selected as alloying elements that further suppress the activity of the Zn-plated layer. The content of one or more of these alloying elements in the plating layer is preferably 0.1 to 30 wt%. Even when coexisting with alumina sol in the plating layer, 0.1wt
If it is less than %, sufficient corrosion resistance improvement effect will not be exhibited.
Moreover, if it exceeds 30 wt%, the sacrificial anticorrosion performance of Zn decreases, resulting in a decrease in corrosion resistance depending on the corrosive environment, and the cost also increases significantly, which is not desirable. The present invention will be specifically described below with reference to Examples and Comparative Examples. Alkaline electrolytic degreasing of cold rolled steel plate (SPCC), 5
After pickling with % hydrochloric acid, washing with water, and plating under the following conditions. Stirring is performed by a pump, the liquid flow rate is approximately 60 m/min, and a pure Zn plate is used as the anode.
The distance between the electrodes was 20 mm, and the liquid temperature was 50°C. The basis weight was all 20g/ m2 . As the alumina sol added to the Zn plating solution, #520 manufactured by Nissan Chemical Co., Ltd. was used. Its properties are as follows. This alumina sol dissolves well in 0.1N or higher hydrochloric acid. Al 2 O 3 content: 20wt% Dispersion medium: Water PH: 4.5 Specific gravity: 1.23 (25℃) Viscosity: 8C.P (20℃) Surface area: 245m 2 /g Stabilizer: Nitric acid Particle shape: Rod to granular particle charge : Positive crystal form: Size of coagulated boehmite particles: 5 to 20 mμ Appearance: Milky colloid liquid Zn plating baths include sulfate bath, chloride bath, pyrophosphate bath, sulfamic acid bath, fluoride bath, and borofluoride bath. Alternatively, mixed baths of these can be used. The following examples mainly show chloride baths, but are not limited thereto. Here, the amount of alumina sol contained in the plating layer and Co,
The total amount of Ni, Fe, and Cr was appropriately controlled by the concentration added in the plating solution. Example 1 Bath composition Zinc chloride 200g/ Potassium chloride 350g/ Alumina sol 1~100ml/ PH4.5, current density 75A/dm 2 Example 2 Bath composition Zinc chloride 200g/ Potassium chloride 300g/ Cobalt chloride 0.1~100g/ Alumina sol 1~ 100ml/PH2.5, current density 100A/dm 2Example 3 Bath composition Zinc chloride 200g/Potassium chloride 300g/Nickel chloride 0.1~100g/Alumina sol 1~100ml/PH3, Current density 75A/dm2Example 4 Bath composition Chloride Zinc 200g / Ammonium chloride 300g / Ferrous chloride 0.1-100g / Alumina sol 1-100ml / PH2, current density 150A/dm 2 Example 5 Bath composition Zinc chloride 200g / Ammonium chloride 300g / Chromium chloride 0.1-100g / Alumina sol 1- 100ml/PH2, current density 75A/ dm2Example 6 Bath composition Zinc chloride 150g/potassium chloride 300g/alumina sol 1-100ml/ as a basic bath, cobalt chloride 0.1-50g/nickel chloride 0.1-50g/ primary chloride Add two or more of iron 0.1~50g/chromium chloride 0.1~50g/ as appropriate to achieve a current density of 100A/d.
I did the plating with m2 . Comparative example For comparison, the addition concentration of alumina sol,
Plated steel sheets for quality evaluation tests were prepared with the addition concentration of one or more ions of Co, Ni, Fe, and Cr outside the range of the above examples. The following tests were conducted on the tempered steel plates obtained in the above Examples and Comparative Examples. The results are shown in Table 1. (1) Plating adhesion evaluation method Evaluation was made based on the peeling state of the plating layer after the Dupont impact test (center of impact diameter 1/2 inch, weight 1 kg, height 50 cm). ◎...No peeling 〇...Very slight peeling △...Slight peeling ×...Excessive peeling (2) Corrosion resistance evaluation method After phosphate treatment (Nippon Parkerizing Co., Ltd. Bonderite #3004), cationic Electrodeposition coating (Nippon Paint Co., Ltd. Power Top U-
30) was applied with a thickness of 10 μm, a cross cut was made to the base steel plate, and the following cycle corrosion tests were conducted: salt spray (JIS Z2371) for 10 hours, dry (60℃) for 2 hours, and wet (50℃, 95℃). % relative humidity) for 6 hours and drying (room temperature) for 6 hours as one cycle, the number of cycles shown at the end of Table 1 was repeated, and evaluation was made based on the bulge width of the cross-cut portion. ◎...0~1mm 〇...1~3mm △...3~6mm ×...6mm or more
【表】【table】
Claims (1)
可溶なアルミナゾルをAl2O3換算で0.01〜3wt％
含有することを特徴とする高耐食性Zn−アルミ
ナ系複合電気めつき鋼板。 ２ 電気Znめつき層中に、Co、Ni、FeおよびCr
より成る群から選択された少なくとも１種の元素
を0.1〜30wt％含有し、さらに濃度0.1N以上の塩
酸に可溶なアルミナゾルをAl2O3換算で0.01〜
3wt％含有することを特徴とする高耐食性Zn−ア
ルミナ系複合電気めつき鋼板。[Claims] 1. Alumina sol soluble in hydrochloric acid with a concentration of 0.1N or more is contained in the electrolytic Zn plating layer in an amount of 0.01 to 3 wt% in terms of Al 2 O 3
Highly corrosion resistant Zn-alumina composite electroplated steel sheet. 2 Co, Ni, Fe and Cr in the electroplated Zn layer
An alumina sol containing 0.1 to 30 wt% of at least one element selected from the group consisting of 0.01 to 30% by weight and soluble in hydrochloric acid with a concentration of 0.1N or higher, calculated as Al 2 O 3
A highly corrosion-resistant Zn-alumina composite electroplated steel sheet characterized by containing 3wt%.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23245983A JPS60125395A (en) | 1983-12-09 | 1983-12-09 | Zn-alumina composite electroplated steel sheet having high corrosion resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP23245983A JPS60125395A (en) | 1983-12-09 | 1983-12-09 | Zn-alumina composite electroplated steel sheet having high corrosion resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS60125395A JPS60125395A (en) | 1985-07-04 |
| JPS626758B2 true JPS626758B2 (en) | 1987-02-13 |
Family
ID=16939614
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP23245983A Granted JPS60125395A (en) | 1983-12-09 | 1983-12-09 | Zn-alumina composite electroplated steel sheet having high corrosion resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS60125395A (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH01290797A (en) * | 1988-05-17 | 1989-11-22 | Nippon Steel Corp | Composite electroplated steel sheet having superior corrosion resistance |
| US4904545A (en) * | 1987-07-10 | 1990-02-27 | Nkk Corporation | Composite electroplated steel sheet |
| WO2007026841A1 (en) | 2005-09-01 | 2007-03-08 | Mitsubishi Chemical Corporation | Apparatus for heat treatment of polyester particle and method of multistage solid-phase polycondensation of polyester particle |
Families Citing this family (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JP2534280B2 (en) * | 1987-02-05 | 1996-09-11 | 日本パーカライジング株式会社 | Zinc-based composite plating metal material and plating method |
| JPS63199899A (en) * | 1987-02-12 | 1988-08-18 | Nkk Corp | Production of dispersion-galvanized steel sheet having high corrosion resistance |
| JP2562607B2 (en) * | 1987-08-06 | 1996-12-11 | 新日本製鐵株式会社 | Method for producing zinc-chromium composite electroplated steel sheet |
| JP2707085B2 (en) * | 1987-08-06 | 1998-01-28 | 新日本製鐵株式会社 | Zinc-chromium composite electroplated steel sheet |
| JPH01230797A (en) * | 1987-11-26 | 1989-09-14 | Nippon Steel Corp | Zn-ni composite electroplated steel sheet having superior corrosion resistance and workability |
| JPH02270998A (en) * | 1990-03-14 | 1990-11-06 | Nippon Steel Corp | Composite electroplated steel sheet having high corrosion resistance |
| US5283131A (en) * | 1991-01-31 | 1994-02-01 | Nihon Parkerizing Co., Ltd. | Zinc-plated metallic material |
| JPH0718498A (en) * | 1993-07-02 | 1995-01-20 | Kawasaki Steel Corp | Highly corrosion resistant zn-alumina dispersion-plated steel sheet and its production |
-
1983
- 1983-12-09 JP JP23245983A patent/JPS60125395A/en active Granted
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4904545A (en) * | 1987-07-10 | 1990-02-27 | Nkk Corporation | Composite electroplated steel sheet |
| JPH01290797A (en) * | 1988-05-17 | 1989-11-22 | Nippon Steel Corp | Composite electroplated steel sheet having superior corrosion resistance |
| WO2007026841A1 (en) | 2005-09-01 | 2007-03-08 | Mitsubishi Chemical Corporation | Apparatus for heat treatment of polyester particle and method of multistage solid-phase polycondensation of polyester particle |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS60125395A (en) | 1985-07-04 |
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