JPS6343479B2 - - Google Patents
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- Publication number
- JPS6343479B2 JPS6343479B2 JP20398582A JP20398582A JPS6343479B2 JP S6343479 B2 JPS6343479 B2 JP S6343479B2 JP 20398582 A JP20398582 A JP 20398582A JP 20398582 A JP20398582 A JP 20398582A JP S6343479 B2 JPS6343479 B2 JP S6343479B2
- Authority
- JP
- Japan
- Prior art keywords
- coating layer
- corrosion resistance
- layer
- corrosion
- coating
- 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
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- 239000011247 coating layer Substances 0.000 claims description 59
- 230000007797 corrosion Effects 0.000 claims description 59
- 238000005260 corrosion Methods 0.000 claims description 59
- XEEYBQQBJWHFJM-UHFFFAOYSA-N iron Substances [Fe] XEEYBQQBJWHFJM-UHFFFAOYSA-N 0.000 claims description 36
- 229910000831 Steel Inorganic materials 0.000 claims description 28
- 239000010959 steel Substances 0.000 claims description 28
- 229910045601 alloy Inorganic materials 0.000 claims description 24
- 239000000956 alloy Substances 0.000 claims description 24
- 229910052759 nickel Inorganic materials 0.000 claims description 18
- 229910052742 iron Inorganic materials 0.000 claims description 16
- 239000000463 material Substances 0.000 claims description 14
- 229910052698 phosphorus Inorganic materials 0.000 claims description 9
- 229910052782 aluminium Inorganic materials 0.000 claims description 7
- 229910052718 tin Inorganic materials 0.000 claims description 7
- 229910052721 tungsten Inorganic materials 0.000 claims description 7
- 229910052804 chromium Inorganic materials 0.000 claims description 6
- 229910052748 manganese Inorganic materials 0.000 claims description 6
- 229910052750 molybdenum Inorganic materials 0.000 claims description 6
- 229910052796 boron Inorganic materials 0.000 claims description 5
- 239000010410 layer Substances 0.000 description 24
- 238000007747 plating Methods 0.000 description 24
- 239000011701 zinc Substances 0.000 description 21
- 238000000576 coating method Methods 0.000 description 15
- 239000011248 coating agent Substances 0.000 description 14
- 230000000694 effects Effects 0.000 description 12
- 239000000523 sample Substances 0.000 description 12
- 238000010422 painting Methods 0.000 description 11
- 238000012360 testing method Methods 0.000 description 7
- 229910019142 PO4 Inorganic materials 0.000 description 6
- NBIIXXVUZAFLBC-UHFFFAOYSA-K phosphate Chemical compound [O-]P([O-])([O-])=O NBIIXXVUZAFLBC-UHFFFAOYSA-K 0.000 description 6
- 239000010452 phosphate Substances 0.000 description 6
- 239000013078 crystal Substances 0.000 description 5
- 239000002184 metal Substances 0.000 description 5
- 229910052751 metal Inorganic materials 0.000 description 5
- 238000004070 electrodeposition Methods 0.000 description 4
- 230000015572 biosynthetic process Effects 0.000 description 3
- 230000000052 comparative effect Effects 0.000 description 3
- 230000007547 defect Effects 0.000 description 3
- 230000007774 longterm Effects 0.000 description 3
- 239000003973 paint Substances 0.000 description 3
- 239000010935 stainless steel Substances 0.000 description 3
- ROSDSFDQCJNGOL-UHFFFAOYSA-N Dimethylamine Chemical compound CNC ROSDSFDQCJNGOL-UHFFFAOYSA-N 0.000 description 2
- 229910001335 Galvanized steel Inorganic materials 0.000 description 2
- 229910018104 Ni-P Inorganic materials 0.000 description 2
- 229910018536 Ni—P Inorganic materials 0.000 description 2
- 229910001297 Zn alloy Inorganic materials 0.000 description 2
- 238000005275 alloying Methods 0.000 description 2
- 238000007796 conventional method Methods 0.000 description 2
- 230000002950 deficient Effects 0.000 description 2
- 239000008397 galvanized steel Substances 0.000 description 2
- JEIPFZHSYJVQDO-UHFFFAOYSA-N iron(III) oxide Inorganic materials O=[Fe]O[Fe]=O JEIPFZHSYJVQDO-UHFFFAOYSA-N 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000007921 spray Substances 0.000 description 2
- ISIJQEHRDSCQIU-UHFFFAOYSA-N tert-butyl 2,7-diazaspiro[4.5]decane-7-carboxylate Chemical compound C1N(C(=O)OC(C)(C)C)CCCC11CNCC1 ISIJQEHRDSCQIU-UHFFFAOYSA-N 0.000 description 2
- 241001156002 Anthonomus pomorum Species 0.000 description 1
- HCHKCACWOHOZIP-UHFFFAOYSA-N Zinc Chemical compound [Zn] HCHKCACWOHOZIP-UHFFFAOYSA-N 0.000 description 1
- 229910007567 Zn-Ni Inorganic materials 0.000 description 1
- 229910007614 Zn—Ni Inorganic materials 0.000 description 1
- 125000002091 cationic group Chemical group 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000005520 cutting process Methods 0.000 description 1
- 238000005238 degreasing Methods 0.000 description 1
- 230000002542 deteriorative effect Effects 0.000 description 1
- 238000007772 electroless plating Methods 0.000 description 1
- 238000009713 electroplating Methods 0.000 description 1
- 238000011156 evaluation Methods 0.000 description 1
- -1 ferrous metals Chemical class 0.000 description 1
- 150000002500 ions Chemical class 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 238000011160 research Methods 0.000 description 1
- 229920006395 saturated elastomer Polymers 0.000 description 1
- 230000009291 secondary effect Effects 0.000 description 1
- 238000010998 test method Methods 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 1
- 229910052725 zinc Inorganic materials 0.000 description 1
Description
本発明は高耐食性表面処理鋼板に係り、特に亜
鉛系合金被覆層を有する表面処理鋼板に関する。
亜鉛めつき鋼板はめつき層の犠牲防食効果によ
り赤錆発生を防止する効果がすぐれているので従
来から自動車用耐食鋼板としても大量に使用され
ている。しかし最近では自動車用耐食性鋼板の耐
食性に対する要求がますます強くなつており、従
来の亜鉛めつき鋼板程度の耐食性では必ずしも十
分とは言えなくなつてきている。これらの要望に
応えるため電位的に亜鉛めつき層より貴なZn―
Fe，Zn―Ni等の如きZn系合金のめつき鋼板の開
発が行なわれており、既に実用段階に入りつつあ
る状況である。しかしこれらのZn系合金めつき
鋼板は従来のZnめつき鋼板よりも耐食性はすぐ
れているとはいえ、これらはめつき層を電位的に
Feより卑、Znよりも貴としてめつき層の腐食速
度をZnより小さくしているがなおFeより大であ
るので、長期間での耐食性が問題となる高耐食性
表面処理鋼板としてはなお不十分である。
その対策として従来特開昭56−33493、特開昭
56−166389等の如くNi等の単一金属を下層被覆
し、Zn系合金めつきを上層被覆として耐食性を
向上させた鋼板が開示されている。しかしこれら
の鋼板でも、その耐食性はなお十分ではなく、特
に下層被覆が薄目付の場合には著しく耐食性が劣
化する欠点がある。
本発明の目的は高耐食性表面処理鋼板の上記従
来技術の欠点を克服し、溶接性を劣化させること
なく、塗装前の裸の耐食性を向上させると共に、
塗装後特に電着塗装後の耐食性のすぐれた高耐食
性表面処理鋼板を提供するにある。
本発明者らはこの目的を達成するために鋭意研
究を重ねた結果鉄属金属とＰ等よりなるめつきの
下層被覆によつて被覆層の腐食速度を著しく減少
させることができ、かつこの成分系のめつきの組
織は非晶質またはきわめて微細な結晶粒からなる
ものであることを見出し本発明を完成するに至つ
たものであつて、その要旨とするところは次の通
りである。
すなわち、鋼板上に形成されたFe，Ni，Coの
うちより選ばれた１種又は２種以上とＰ，Ｗ，
Ｂ，Moのうちより選ばれた１種より成る第１被
覆層と、前記第１被覆層上に形成されたFe，Ni，
Co、Sn，Al，Crのうちより選ばれた１種または
２種以上を含有するZn系合金より成る第２被覆
層と、を有して成ることを特徴とする高耐食性表
面処理鋼板である。
本発明の詳細を本発明者らの実験結果に基いて
説明する。
電解脱脂等通常のめつき原板処理工程を経て製
造された鋼板に先ずFe，Ni，CoのFe族元素のう
ちより選ばれた１種または２種以上とＰ，Ｗ，
Ｂ，Moのうちより選ばれた１種の元素より成る
Fe族合金めつきを第１被覆層として形成する。
これらのFe族合金めつきは例えばNi―Ｐはワツ
ト浴に亜リン酸を加えた溶液から電気めつきする
か、もしくはブレンナー浴から無電解めつきする
ことによつて可能であり、Fe―Ｐ，Co―Ｐ，Fe
―Ni―Ｐなども同様にめつき液に亜リン酸を添
加することによつて可能である。またＢを含む
Fe族合金めつきはジメチルアミンボラーなどの
還元剤を添加することにより、またＷ，Moを含
むFe族合金めつきはそれぞれのFe族めつきの溶
液にＷ，Moの酸化物等の形で添加することによ
つていずれもめつきすることが可能である。
これらの第１被覆層を形成するFe族合金めつ
きは、Fe族元素の単一金属めつきと異なり非晶
質をなるか、もしくは極めて微細な結晶粒から成
る組織を有するめつきとなるのが特徴である。そ
のため薄目付の場合でも均一な被覆となり、地鉄
鋼板の表面に被覆率が高く欠陥の少い被覆層を形
成することができる。
上記第１被覆層を形成するFe族系合金めつき
中のFe族元素の合計含有量は70〜99％に限定す
べきであることが判明した。その理由は、70％未
満では電流効率が著しく減少し製造コストが高く
なり、かつ技術的にも困難を伴い、また99％を越
すとＰ，Ｗ，Ｂ，Moを含有しないFe族金属とほ
ぼ同一の性質となり好ましくないからであつて、
好ましくは80〜95％の範囲が適当である。
上記第１被覆層を形成するFe族系合金の付着
量は0.05〜５ｇ／m2の範囲に限定すべきあつて
0.1〜３ｇ／m2の範囲は最も好ましい。その理由
は付着量が0.05ｇ／m2未満では耐食性向上効果が
少く、また５ｇ／m2を越して被覆層の厚さが厚く
なつても耐食性向上効果が飽和して不経済であ
り、更に第２被覆層の耐食性を劣化する場合があ
るからである。
次に上記第１被覆層上にFe，Ni，Co，Sn，
Al，Mn，Crのうちより選ばれた１種または２種
以上を含有するZn系合金より成る第２被覆層を
形成する。これらのZn系合金めつき硫酸塩浴も
しくは塩化物浴のZnめつき溶液にFe，Ni，Co，
Sn，Al，Mn，Crの各添加元素イオンを添加する
ことにより任意の含有量の第２層を形成すること
ができる。これらの元素を第２被覆層に添加する
ことにより、めつき層の電位をより貴とすること
ができ腐食速度を減少させる効果がある。更に
Znにこれらの元素を合金することにより局部電
池が均一に形成されるためZnの単一めつき層に
比較して均一で緻密な燐酸塩結晶が生成し、燐酸
塩処理性が向上する効果もある。上記第２被覆層
を形成するZn系合金めつき中のFe，Ni，Co，
Sn，Al，Mn，Crの１種または２種以上の合計含
有量は５〜95％の範囲に限定すべきであるが、特
に８〜80％の範囲が最適である。その理由は上記
合金元素の添加量が５％未満ではZn合金として
腐食速度を減少させる効果に乏しく、また95％を
越える過剰の添加ではZnの犠牲防食性が著しく
小さくなるためである。而してかかるZn系合金
より成る第２被覆層の付着量は６〜60ｇ／m2に限
定すべきであり、特に10〜50ｇ／m2の範囲が最適
であることが判明した。その理由はZn系合金被
覆層が６ｇ／m2未満の場合には、犠牲防食作用を
有するZn量が少いために耐食性が劣り、また60
ｇ／m2を越える過剰付着量では、めつき層が過度
に厚くなつてプレス加工性および溶接性を劣化す
るからである。
かくの如き限定範囲のZn系合金より成る第２
被覆層を形成することにより上記腐食速度を著し
く減少する効果のほかに、塗装後の耐食性も向上
する。これは塗装後の塗膜欠陥部よりの腐食、ま
たは塗膜下腐食が開始された場合でも、該腐食生
成物による塗膜ふくれ等の欠陥の発生を防止し、
その耐食性を向上するからである。
上記の如く通常のめつき原板処理をした鋼板上
に第１被覆層を形成し、更にその上に第２被覆層
を形成することによつて本発明による高耐食性表
面処理鋼板が得られるが、各被覆層の付着量は適
正でなければならず、そのため第１被覆層の付着
量は0.05〜５ｇ／m2と限定し、第２被覆層の付着
量は６〜60ｇ／m2と限定すべきであることは既に
述べたとおりであるが、第１被覆層の付着量と第
２被覆層の付着量との比も極めて重要であつて、
この比は１／５以下である必要がある。すなわ
ち、第２層のZn系合金めつき被覆層は第１層の
Fe族系合金めつき層の５倍以上の付着量を有す
ることによつて始めて長期的な耐食性のすぐれた
表面処理鋼板が得られることが判明した。その理
由は第１層が第２層の１／５を越える付着量を有
する場合には、犠牲防食能が少いために表面加工
部となる第１層の耐食性が劣化し、更に長期間の
耐食性試験においてかえつて耐食性が劣化する場
合があるからである。その結果、本発明では第１
層の被覆層と第２層の被覆層との付着量の比を
１／５以下に限定した。
かくの如き第１層および第２層を有することに
より、塗装前の裸の耐食性は勿論、塗装後の耐食
性、特に電着塗装後の耐食性のすぐれた表面処理
鋼板を得ることができた。
実施例
本発明による種々の高耐食性表面処理鋼板と本
発明による限定条件の表面処理鋼板について塗装
前の裸の状態における耐食性および塗装後の耐食
性について比較試験した。
すなわち、第１表に示す如き本発明外の供試材
No.１〜６と本発明による供試材No.７〜14の14種類
について試験した。本発明外の供試材について
は、No.１は下層被覆層なしにて上層被覆層をZn
―10％Niめつきを15ｇ／m2施し、No.２について
は下層被覆層をNiのみの１ｇ／m2とし、その上
層被覆層をNo.１と同一条件のZn―10％Niめつき
を15ｇ／m2施した。以下第１表に記載のとおり供
試材No.３，４，５，６に従来法等の本発明外条件
でそれぞれ被覆層を形成した。
本発明による供試材については、No.７はFe―
30％Moの下層被覆層を１ｇ／m2施し、その上に
供試材No.１と同様にZn―10％Niめつきを15ｇ／
m2施し、供試材No.８についてはNi―５％Ｐの下
層被覆層めつきを0.1ｇ／m2施し、その上に供試
材No.１と同様にZn―10％Niめつきを15ｇ／m2施
し、以下同様に第１表記載のとおり供試材No.９は
Fe―15％Ｐ、No.10はCo―３％Ｐ、No.11はCo―25
％Ｗ、No.12はNi―10％Co―５％Ｐ、No.13はNi―
25％Ｂ、No.14はNi―10％Ｐの下層被覆層をそれ
ぞれ
The present invention relates to a highly corrosion-resistant surface-treated steel sheet, and particularly to a surface-treated steel sheet having a zinc-based alloy coating layer. Galvanized steel sheets have been used in large quantities as corrosion-resistant steel sheets for automobiles because they have an excellent effect of preventing the occurrence of red rust due to the sacrificial anticorrosion effect of the galvanized layer. However, in recent years, there has been an increasingly strong demand for the corrosion resistance of corrosion-resistant steel sheets for automobiles, and the corrosion resistance of conventional galvanized steel sheets is no longer necessarily sufficient. In order to meet these demands, Zn-- which is potentially more noble than the galvanized layer.
Steel sheets plated with Zn-based alloys such as Fe, Zn-Ni, etc. are being developed and are already entering the stage of practical use. However, although these Zn-based alloy-plated steel sheets have better corrosion resistance than conventional Zn-plated steel sheets, these
Although the corrosion rate of the plated layer is lower than Fe and nobler than Zn, it is still higher than Fe, so it is still insufficient as a highly corrosion-resistant surface-treated steel sheet where long-term corrosion resistance is a problem. It is. As a countermeasure to this problem, the conventional Japanese Patent Application Laid-Open No. 56-33493,
No. 56-166389, etc., discloses a steel plate coated with a single metal such as Ni as a lower layer and coated with a Zn-based alloy as an upper layer to improve corrosion resistance. However, even with these steel plates, the corrosion resistance is still not sufficient, and particularly when the lower layer coating has a light basis weight, there is a drawback that the corrosion resistance is significantly deteriorated. The purpose of the present invention is to overcome the drawbacks of the above-mentioned conventional techniques of highly corrosion-resistant surface-treated steel sheets, improve the corrosion resistance of the bare surface before painting without deteriorating the weldability, and
It is an object of the present invention to provide a highly corrosion-resistant surface-treated steel sheet that has excellent corrosion resistance after painting, especially after electrodeposition painting. The present inventors have conducted extensive research to achieve this objective, and have found that the corrosion rate of the coating layer can be significantly reduced by a plating lower layer coating made of ferrous metals and P, etc. The present invention was completed by discovering that the plating structure is amorphous or composed of extremely fine crystal grains, and the gist thereof is as follows. In other words, one or more selected from Fe, Ni, and Co formed on a steel plate and P, W,
A first coating layer made of one selected from B, Mo, and Fe, Ni,
and a second coating layer made of a Zn-based alloy containing one or more selected from among Co, Sn, Al, and Cr. . The details of the present invention will be explained based on the experimental results of the present inventors. First, one or more selected from Fe group elements such as Fe, Ni, and Co, and P, W,
Consists of one element selected from B and Mo
Fe group alloy plating is formed as the first coating layer.
These Fe group alloy platings are possible, for example, by electroplating Ni-P from a solution containing phosphorous acid in a Watts bath or by electroless plating from a Brenner bath; ,Co-P,Fe
-Ni-P etc. can also be produced by adding phosphorous acid to the plating solution. Also includes B
Fe group alloy plating can be achieved by adding a reducing agent such as dimethylamine borer, and Fe group alloy plating containing W and Mo can be achieved by adding oxides of W and Mo to the respective Fe group plating solutions. By doing this, it is possible to plate both. Unlike single metal plating of Fe group elements, the Fe group alloy plating that forms these first coating layers is either amorphous or has a structure consisting of extremely fine crystal grains. It is characterized by Therefore, even in the case of a thin basis weight, a uniform coating is obtained, and a coating layer with a high coverage rate and few defects can be formed on the surface of the base steel sheet. It has been found that the total content of Fe group elements in the Fe group alloy plating forming the first coating layer should be limited to 70-99%. The reason for this is that if it is less than 70%, the current efficiency will decrease significantly, manufacturing costs will increase, and it will be technically difficult. This is because they have the same characteristics, which is undesirable.
Preferably, a range of 80 to 95% is appropriate. The amount of Fe group alloy that forms the first coating layer should be limited to a range of 0.05 to 5 g/ m2 .
A range of 0.1 to 3 g/m 2 is most preferred. The reason for this is that if the coating amount is less than 0.05 g/m 2 , the effect of improving corrosion resistance will be small, and even if the thickness of the coating layer exceeds 5 g/m 2 , the effect of improving corrosion resistance will be saturated and it will be uneconomical. This is because the corrosion resistance of the second coating layer may be deteriorated. Next, Fe, Ni, Co, Sn,
A second coating layer made of a Zn-based alloy containing one or more selected from among Al, Mn, and Cr is formed. Fe, Ni, Co,
By adding ions of Sn, Al, Mn, and Cr, the second layer can have an arbitrary content. By adding these elements to the second coating layer, the potential of the plating layer can be made more noble, which has the effect of reducing the corrosion rate. Furthermore
By alloying these elements with Zn, a local cell is formed uniformly, resulting in the formation of more uniform and dense phosphate crystals than a single plated layer of Zn, which also has the effect of improving phosphate treatment properties. be. Fe, Ni, Co, in the Zn alloy plating forming the second coating layer,
The total content of one or more of Sn, Al, Mn, and Cr should be limited to a range of 5 to 95%, and a range of 8 to 80% is particularly optimal. The reason for this is that if the amount of the alloying element added is less than 5%, the Zn alloy will not be effective in reducing the corrosion rate, and if it is added in excess of 95%, the sacrificial corrosion protection of Zn will be significantly reduced. Therefore, it has been found that the amount of the second coating layer made of the Zn-based alloy should be limited to 6 to 60 g/m 2 , and in particular, a range of 10 to 50 g/m 2 is optimal. The reason for this is that when the Zn-based alloy coating layer is less than 6 g/m2, the amount of Zn that has a sacrificial anticorrosion effect is small, resulting in poor corrosion resistance.
This is because if the coating amount exceeds g/m 2 , the plated layer becomes excessively thick and the press workability and weldability deteriorate. The second material is made of a Zn-based alloy in a limited range as described above.
By forming a coating layer, in addition to the effect of significantly reducing the corrosion rate mentioned above, corrosion resistance after painting is also improved. This prevents defects such as blistering of the paint film due to corrosion products even if corrosion from defective parts of the paint film or corrosion under the paint film starts after painting.
This is because it improves its corrosion resistance. A highly corrosion-resistant surface-treated steel sheet according to the present invention can be obtained by forming a first coating layer on a steel sheet that has been subjected to the usual plating original plate treatment as described above, and further forming a second coating layer thereon. The amount of each coating layer must be appropriate, so the amount of the first coating layer is limited to 0.05 to 5 g/ m2 , and the amount of the second coating layer is limited to 6 to 60 g/ m2 . As already mentioned, the ratio of the amount of the first coating layer to the amount of the second coating layer is also extremely important.
This ratio needs to be 1/5 or less. In other words, the second Zn-based alloy plating coating layer is the same as the first layer.
It has been found that a surface-treated steel sheet with excellent long-term corrosion resistance can only be obtained by having a coating weight of at least 5 times that of the Fe group alloy plating layer. The reason for this is that when the first layer has a coating weight that exceeds 1/5 of the second layer, the sacrificial anticorrosion ability is low, so the corrosion resistance of the first layer, which is the surface treated part, deteriorates, and the long-term corrosion resistance deteriorates. This is because the corrosion resistance may actually deteriorate in the test. As a result, in the present invention, the first
The ratio of the amount of adhesion between the coating layer and the coating layer of the second layer was limited to 1/5 or less. By having such a first layer and a second layer, it was possible to obtain a surface-treated steel sheet that not only has excellent corrosion resistance before coating but also has excellent corrosion resistance after coating, especially corrosion resistance after electrodeposition coating. Examples Various highly corrosion-resistant surface-treated steel sheets according to the present invention and surface-treated steel sheets under limited conditions according to the present invention were compared and tested for corrosion resistance in a bare state before painting and corrosion resistance after painting. That is, test materials other than the present invention as shown in Table 1
Fourteen types of specimens Nos. 1 to 6 and test materials Nos. 7 to 14 according to the present invention were tested. Regarding test materials other than the present invention, No. 1 has no lower coating layer and the upper coating layer is Zn.
-10%Ni plating was applied at 15g/ m2 , and for No.2, the lower coating layer was Ni only at 1g/ m2 , and the upper coating layer was Zn-10%Ni plating under the same conditions as No.1. was applied at a rate of 15g/ m2 . As shown in Table 1 below, coating layers were formed on sample materials Nos. 3, 4, 5, and 6 using conventional methods and other conditions outside the present invention. Regarding the sample material according to the present invention, No. 7 is Fe-
A lower coating layer of 30%Mo was applied at 1g/ m2 , and on top of that, 15g/m2 of Zn-10%Ni plating was applied in the same manner as test material No.1.
For sample material No. 8 , a Ni-5%P lower coating layer was applied at 0.1 g/m2, and on top of that, Zn-10% Ni plating was applied in the same manner as test material No. 1. 15g/ m2 was applied, and similarly as shown in Table 1, sample material No. 9 was
Fe-15%P, No.10 is Co-3%P, No.11 is Co-25
%W, No.12 is Ni-10%Co-5%P, No.13 is Ni-
25%B and No.14 are Ni-10%P lower coating layers, respectively.
【表】【table】
【表】
めつきした上に、供試材No.９はNo.１と同一の上層
被覆層、No.10〜12はいずれも供試材No.３と同一の
上層被覆層、No.13〜14はいずれも供試材No.５と同
一の上層被覆層を形成させた。
かくして得た比較材No.１〜６、本発明材No.７〜
14の各Zn系合金被覆鋼板の裸の耐食性および塗
装後の耐食性は第１表のとおりである。第１表に
おいて耐食性の評価は下記のとおりである。
〇印………良好
△印………やや良好
×印………劣る
なお、本実施例における耐食性は次の基準によ
つて評価した。
(イ) 裸の耐食性
JIS Z2371に基く塩水噴霧試験方法において、
240時間後の赤錆発生を評価した。
(ロ) 塗装後の耐食性
各供試材の燐酸塩処理し、1.5〜2.0ｇ／m2の燐
酸塩を付着させた後、カチオン型電着塗装を17μ
ｍの厚さに施し、クロスカツト後JISZ2371に基
く塩水噴霧試験を行い、1200時間後の塗装のふく
れと、その後の板厚減少とを評価した。
第１表に示した実施例より明らかなとおり、供
試材No.１，２と供試材No.７，８，９および供試材
No.３，４とNo.10，11，12、更に供試材No.５，６と
No.13，14とはそれぞれ上層被覆層は同一であるに
拘らず、比較例は本発明例に比して裸の耐食性お
よび塗装後の耐食性が著しく劣るのは、第１層の
下層被覆層が欠除するか、または従来例のNo.２，
４，６の如く下層被覆層がFe族金属単味であつ
て本発明の要件を満足しないためであつて、本発
明による第１被覆層による効果を如実に示すもの
である。その結果本発明例による裸の耐食性およ
び塗装後の耐食性はいずれも比較例に比し極めて
すぐれた結果を示している。
第１表にて示す本発明の実施例では第１被覆層
はFe族元素の１種および２種のみを示したが、
Fe，Ni，CoはFe族元素として近似の性質を有
し、Fe，Ni，Coの３種元素にＰ，Ｗ，Ｂ，Mo
のうちより選ばれた１種を含む場合も同様な効果
を示すことを確認した。
上記実施例より明らかな如く、本発明による高
耐食性表面処理鋼板は、電解脱脂等通常のめつき
原板処理を施した鋼板上に、先ずFe，Ni，Coの
鉄族元素とＰ，Ｗ，Ｂ，Moのうちの１種とのFe
族系合金めつきの第１被覆層を形成し、更にその
上にFe，Ni，Co，Sn，Al，Mn，Crの１種また
は２種以上を含有するZn系合金より成る第２被
覆層を形成したものであつて、特に第１被覆層中
のFe族元素の含有量ならびに第１層、第２層の
付着量を限定することにより裸の耐食性は勿論、
塗装後特に電着塗装後の耐食性の極めてすぐれた
高耐食性表面処理鋼板を得ることができた。
これは第１被覆層を形成するFe族合金めつき
は従来のNi等の単一金属めつきと異なり、非晶
質または極めて微細な結晶粒よりなる組織を有す
るために、それ自体が耐食性が良好であるばかり
ではなく、薄目付の場合でも均一な被覆となり、
地鉄鋼板の表面に被覆率が高く欠陥の少い被覆層
を形成することができることに因るものであつ
て、本発明の大きな特徴の一つである。この第１
層上に更に第２層の上層被覆層があるので、上層
被覆層に欠陥部が発生しても、その対応部分の第
２被覆層の耐食性が良好のため腐食の進展が防止
される。
上記本発明の効果のほかに本発明鋼板の第２層
のZn系合金被覆層の存在によつて局部電池が均
一に形成されるので、Znの単一めつき層に比較
して均一で緻密な燐酸塩結晶が生成し、燐酸塩処
理性が向上するほか上記第１、第２層の形成いよ
つても溶接性を損わない副次的効果もあるので、
自動車用耐食鋼板等広い用途に使用されてすぐれ
た耐食効果が期待できる。[Table] In addition to plating, sample material No. 9 has the same upper coating layer as No. 1, Nos. 10 to 12 have the same upper coating layer as sample material No. 3, and No. 13 In all of Samples No. 1 to 14, the same upper coating layer as Sample No. 5 was formed. Comparative materials No. 1 to 6 and invention materials No. 7 to 6 thus obtained.
Table 1 shows the corrosion resistance of each of the 14 Zn-based alloy coated steel sheets, both naked and after coating. In Table 1, the evaluation of corrosion resistance is as follows. ○ mark: Good △ mark: Slightly good × mark: Poor In addition, the corrosion resistance in this example was evaluated according to the following criteria. (a) Bare corrosion resistance In the salt spray test method based on JIS Z2371,
The occurrence of red rust after 240 hours was evaluated. (b) Corrosion resistance after painting After each sample material was phosphate treated and 1.5 to 2.0 g/m 2 of phosphate was applied, cationic electrodeposition coating was applied to 17 μm.
After cross-cutting, a salt water spray test based on JIS Z2371 was conducted to evaluate the blistering of the coating after 1200 hours and the subsequent decrease in board thickness. As is clear from the examples shown in Table 1, sample materials No. 1, 2, sample materials No. 7, 8, 9, and sample materials
No. 3, 4, No. 10, 11, 12, and sample materials No. 5, 6.
Although the upper coating layer is the same as that of Nos. 13 and 14, the comparative example is significantly inferior in bare corrosion resistance and post-painting corrosion resistance compared to the inventive example because the lower coating layer of the first layer is is missing, or conventional example No. 2,
This is because the lower coating layer as in Nos. 4 and 6 is made of only Fe group metal and does not satisfy the requirements of the present invention, and clearly shows the effect of the first coating layer according to the present invention. As a result, both the bare corrosion resistance and the corrosion resistance after coating according to the examples of the present invention are extremely superior to those of the comparative examples. In the examples of the present invention shown in Table 1, the first coating layer contained only one and two types of Fe group elements,
Fe, Ni, and Co have similar properties as Fe group elements, and P, W, B, and Mo are the three elements of Fe, Ni, and Co.
It was confirmed that a similar effect was obtained when one of the selected types was included. As is clear from the above examples, the highly corrosion-resistant surface-treated steel sheet according to the present invention is produced by first adding iron group elements such as Fe, Ni, and Co to a steel sheet that has been subjected to ordinary plating original plate treatment such as electrolytic degreasing. , Fe with one of Mo
Forming a first coating layer plated with a Zn-based alloy, and further forming a second coating layer made of a Zn-based alloy containing one or more of Fe, Ni, Co, Sn, Al, Mn, and Cr. In particular, by limiting the content of Fe group elements in the first coating layer and the amount of deposits of the first and second layers, it is possible to improve not only bare corrosion resistance but also
It was possible to obtain a highly corrosion-resistant surface-treated steel sheet with extremely excellent corrosion resistance after painting, especially after electrodeposition painting. This is because the Fe group alloy plating that forms the first coating layer has a structure consisting of amorphous or extremely fine crystal grains, unlike conventional single metal plating such as Ni, so it itself has no corrosion resistance. Not only is it good, but it also provides uniform coverage even in the case of thin coatings.
This is due to the ability to form a coating layer with a high coverage rate and few defects on the surface of the base steel plate, and is one of the major features of the present invention. This first
Since there is a second upper coating layer on top of the second layer, even if a defective portion occurs in the upper coating layer, the second coating layer in the corresponding portion has good corrosion resistance, so that the progress of corrosion is prevented. In addition to the above-mentioned effects of the present invention, the presence of the second Zn-based alloy coating layer of the steel sheet of the present invention allows local batteries to be formed uniformly, which is more uniform and dense than a single Zn plated layer. In addition to the formation of phosphate crystals, which improves phosphate treatment properties, there is also the secondary effect that the formation of the first and second layers does not impair weldability.
It is expected to be used in a wide range of applications, such as corrosion-resistant steel sheets for automobiles, and has excellent corrosion resistance effects.
Claims (1)
選ばれた１種又は２種以上とＰ，Ｗ，Ｂ，Moの
うちより選ばれた１種より成る第１被覆層と、前
記第１被覆層上に形成されたFe，Ni，Co，Sn，
Al，Mn，Cr、のうちより選ばれた１種または２
種以上を含有するZn系合金よりなる第２被覆層
と、を有して成ることを特徴とする高耐食性表面
処理鋼板。 ２ 前記第１被覆層の付着量は0.05〜５ｇ／m2で
あつてFe，Ni，Coのうちより選ばれた鉄族元素
を70〜99％含有し、前記第２被覆層の付着量は６
〜60ｇ／m2であつてFe，Ni，Co，Sn，Al，Mn，
Crのうちより選ばれた１種または２種以上を５
〜95％含有する特許請求の範囲の第１項に記載の
高耐食性表面処理鋼板。 ３ 前記第１被覆層と前記第２被覆層の付着量の
比は１／５以下である特許請求の範囲の第１項も
しくは第２項に記載の高耐食性表面処理鋼板。[Scope of Claims] 1. A first material formed on a steel plate and comprising one or more selected from Fe, Ni, and Co and one selected from P, W, B, and Mo. Fe, Ni, Co, Sn, formed on the coating layer and the first coating layer.
One or two selected from Al, Mn, Cr
A highly corrosion-resistant surface-treated steel sheet comprising: a second coating layer made of a Zn-based alloy containing at least one Zn-based alloy; 2 The first coating layer has an adhesion amount of 0.05 to 5 g/m 2 and contains 70 to 99% of iron group elements selected from Fe, Ni, and Co, and the second coating layer has an adhesion amount of 6
~60g/ m2 and Fe, Ni, Co, Sn, Al, Mn,
5 of one or more selected types of Cr
The highly corrosion-resistant surface-treated steel sheet according to claim 1, containing ~95%. 3. The highly corrosion-resistant surface-treated steel sheet according to claim 1 or 2, wherein the ratio of the adhesion amounts of the first coating layer and the second coating layer is 1/5 or less.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20398582A JPS5993897A (en) | 1982-11-20 | 1982-11-20 | Surface treated steel sheet having high corrosion resistance |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| JP20398582A JPS5993897A (en) | 1982-11-20 | 1982-11-20 | Surface treated steel sheet having high corrosion resistance |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| JPS5993897A JPS5993897A (en) | 1984-05-30 |
| JPS6343479B2 true JPS6343479B2 (en) | 1988-08-30 |
Family
ID=16482873
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| JP20398582A Granted JPS5993897A (en) | 1982-11-20 | 1982-11-20 | Surface treated steel sheet having high corrosion resistance |
Country Status (1)
| Country | Link |
|---|---|
| JP (1) | JPS5993897A (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02283091A (en) * | 1988-12-20 | 1990-11-20 | Pfu Ltd | Printed board and manufacture thereof |
Families Citing this family (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH0768635B2 (en) * | 1986-03-29 | 1995-07-26 | 日新製鋼株式会社 | Electric Zn alloy plated steel sheet with excellent paintability |
| GB2230537B (en) * | 1989-03-28 | 1993-12-08 | Usui Kokusai Sangyo Kk | Heat and corrosion resistant plating |
| DE4136038C2 (en) * | 1990-11-02 | 1994-06-16 | Usui Kokusai Sangyo Kk | Welded steel tube with high corrosion resistance of the inner surface and process for its production |
| JP2010270353A (en) * | 2009-05-19 | 2010-12-02 | Nippon Steel Corp | Plated steel material excellent in glossy appearance and corrosion resistance, and method of manufacturing the same |
| CN103074649B (en) * | 2013-01-21 | 2015-10-07 | 四川重汽王牌兴城液压件有限公司 | Strengthen mine individual hydraulic prop cylinder tube preserving method |
-
1982
- 1982-11-20 JP JP20398582A patent/JPS5993897A/en active Granted
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH02283091A (en) * | 1988-12-20 | 1990-11-20 | Pfu Ltd | Printed board and manufacture thereof |
Also Published As
| Publication number | Publication date |
|---|---|
| JPS5993897A (en) | 1984-05-30 |
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