JPH0433875B2 - - Google Patents

Description

[Detailed description of the invention]

(Industrial Application Field) The present invention provides highly corrosion-resistant electrical composite plating containing fine particles coated with a thin film of an inorganic or organic material (this treatment is referred to as microencapsulation) in the plating layer. It concerns steel plates. (Prior Art) In recent years, in cold winter regions such as North America and Europe, rock salt, calcium chloride, etc. are being sprayed to prevent roads from freezing, and the environment in which automobiles are used has become increasingly harsh. In such an environment, there is an urgent need to develop highly corrosion-resistant galvanized steel sheets for automobiles that do not develop red rust or develop holes for a certain period of time. In response to this, there are two developments. In other words, the development of thick electroplated steel sheets in countries with low electricity costs, such as the United States and Canada, and the development of thick electroplated steel sheets in countries such as Japan, where electricity costs are high and users have strict requirements for weldability, plating adhesion, etc. An electroplated steel sheet with a thin coating weight and high corrosion resistance has been developed. The present invention relates to the latter, and up to now, thin electroplated steel sheets include Zn-Fe, Zn-Ni, Zn-Fe, Zn-Ni,
Zn alloy coated steel sheets such as Zn-Mn and Zn or Zn
-An organic multilayer electroplated steel sheet has been developed in which a chromate + organic resin coating is applied on the Ni alloy plating layer. However, the above-mentioned alloy-plated and organic multi-layer electroplated steel sheets have a light weight of about 20 to 30 g/m ² , and the current goal of domestic and foreign automakers is ``5-year resistance to external rust'' (red rust on the exterior of the automobile is 5 years). - "10 years of perforation resistance (no perforation from the outside or inside of the vehicle for 10 years)" In particular, it is said that the requirement of "10 years of perforation resistance" has not yet been met. It is being said. Therefore, recently, in order to produce galvanized steel sheets with even higher corrosion resistance, the production of so-called highly corrosion-resistant composite galvanized steel sheets has been studied, in which fine particles with anti-corrosion properties are dispersed and co-deposited in the galvanized layer. ing. (Problems to be solved by the invention) Composite galvanized steel sheets can provide various properties to the galvanized layer through dispersed and eutectoid fine particles, and there is a tendency for composite galvanized steel sheets to be often used as galvanized steel sheets with new functions. It is in. For example, recently, composite galvanized steel sheets exhibiting high corrosion resistance have been published in Japanese Patent Application Laid-Open No. 60-96786,
It has been introduced in many patent publications such as 60-211094 to 211096. JP-A-60-96786 discloses that anticorrosion pigments (e.g., PbCrO ₄ ,
This paper describes a composite galvanized steel sheet in which SrCrO ₄ , ZnCrO ₄ , BaCrO ₄ , Zn ₃ (PO ₄ ) _2, etc.) are dispersed and eutectoid, and a method for producing the same. This composite plated steel sheet can be evaluated as having superior corrosion resistance against external rust and pitting compared to the alloy plating and organic multilayer electroplating. However, JP-A-60-
A laminated steel sheet containing only a slightly soluble chromate anticorrosive pigment (almost insoluble in an aqueous solution) as disclosed in Japanese Patent No. 96786 has not reached the level of corrosion resistance targeted by the present inventors. The results of the accelerated corrosion test conducted by the present inventors are shown in FIG. Here, the hot-dip galvanizing (90 g/m ² ) was at the level of 10-year perforation resistance, and was used as a comparison material. From the figure, during Zn plating
Composite galvanized steel sheets in which only BaCrO ₄ particles are dispersed have inferior pitting resistance compared to hot-dip galvanized steel sheets (90 g/m ² ). Furthermore, it is difficult to obtain a matted layer in which a rust-preventing pigment such as a hardly soluble chromate is sufficiently dispersed and precipitated. The reason for this is that anti-rust pigments such as poorly soluble chromates have a surface potential of almost zero in a galvanizing bath, so even if they are electrolytically treated using a steel plate as a cathode, they will remain in the bath.
Zn ²⁺ ions preferentially precipitate, making it difficult for the anticorrosive pigment to precipitate onto the plating layer, and as a result, a composite plated steel sheet with stable corrosion resistance cannot be obtained. Also,
JP-A-60-211095 discloses a composite plated steel sheet in which chromium, alumina (Al ₂ O ₃ ), silica (SiO ₂ ), etc. are dispersed and eutectoid in a Zn-Ni alloy plated layer. ing. This publication uses chromium chloride (CrCl ₃ ) as a chromium source in the plating bath, but chromium chloride dissolves in the plating bath and releases Cr ³⁺ ions. When electrolytically treated in this bath using a steel plate as a cathode, metallic chromium and chromium chloride (Cr ₂ O ₃ · nH ₃ O) are precipitated, and the plating layer is Zn-Ni.
−Cr (+Cr ₂ O ₃・nH ₃ O), and a composite plated steel sheet with alumina and silica eutectoid is manufactured. This composite plated steel sheet has a small improvement in corrosion resistance compared to Zn-Ni alloy plating or Zn-Ni-Cr (+Cr ₂ O ₃ nH ₃ O) plating layer, and as shown in Figure 1, Zn-Ni-Cr
-As shown in the accelerated corrosion test results for Al ₂ O ₃ composite plated steel sheets, the 10-year perforation resistance has not yet been achieved. In other words, Zn-Ni-Cr-Al ₂ O ₃ composite galvanized steel sheet and hot-dip galvanized steel sheet (90g/
m ² ). FIG. 1 shows the corrosion depth results after 50 cycles of the composite corrosion test of the composite plated steel plate of the present invention and the uncoated comparative material. (Note) The contents of the complex corrosion test cycle are

[Table] Note Evaluation sample 1: Zn-0.3%BaCrO ₄ composite plated steel plate (JP-A-Sho
60-96786 publication conditions) 2: Zn-1%Ni-1%Cr-1%Al ₂ O ₃ composite plated steel plate (plated under the conditions of JP-A-60-211095 publication) 3: Zn-10%Co-4%BaCrO ₄ (SiO ₂ thin film coating) (composite plating according to the present invention) 4: Hot-dip zinc thick plating (90 g/m ² ) (Means for solving the problem) Therefore, the present invention They were acutely aware of the need to develop a composite galvanized steel sheet with higher corrosion resistance, and as a result of intensive study, as shown in Figure 1, they succeeded in dispersing micro-encapsulated fine particles by coating the surface with an ultra-thin film. It has been found that a toughened steel sheet provided with a eutectoid toughened layer has excellent properties as a rust-preventing steel sheet for automobiles, and is particularly excellent in rust resistance and porosity resistance. That is, the gist of the present invention is as follows: (1) Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions having an anticorrosion effect in a plating layer, a compound that itself has corrosion-inhibiting ability, or both. , SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb,
A highly corrosion-resistant electrical composite plated steel sheet, characterized in that it has an alloy plating layer consisting of one or more of Pb, Ni, and Mo on one or both sides of the steel sheet. (2) Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions that have an anticorrosion effect in the plating layer, a compound that itself has a corrosion-inhibiting ability, or both, are mixed with SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb,
A multi-layer steel plate having an alloy plating layer consisting of one or more types of Pb, Ni, and Mo, and an electroplating layer each consisting of one or more types of Zn, Fe, Co, Ni, Mn, and Cr on top of the alloy plating layer. A highly corrosion-resistant electrically composite galvanized steel sheet, characterized in that it has on one or both sides thereof. (3) Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions that have an anticorrosion effect in the plating layer, a compound that itself has a corrosion-inhibiting ability, or both, are mixed with SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb,
A highly corrosion-resistant electrical composite material comprising a laminated layer consisting of an alloy plating layer made of one or more of Pb, Ni, and Mo and a resin coating film on one or both sides of a steel plate. Steel plate. (4) Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions having an anti-corrosion effect in the plating layer, a compound that itself has corrosion-inhibiting ability, or both, are mixed with SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb,
An alloy plating layer made of one or more of Pb, Ni, and Mo, an electroplated layer each made of one or more of Fe, Co, Ni, Mn, and Cr, and a resin coating on top of that. This is a highly corrosion-resistant electrically composite plated steel sheet characterized by having a laminated film on one or both sides of the steel sheet. (Function) The structure of the composite plated steel sheet of the present invention will be explained in detail. Figures 2a, b, c, and d show cross-sectional views of the composite plated steel plate model of the present invention. In FIG. 2a, 1 is a steel plate, which is a thin steel plate whose surface has been cleaned through a normal surface treatment steel plate manufacturing process. 2 is zinc or zinc and Co, Mn, Cr, Sn, Sb,
This is an alloy plating layer made of one or more of Pb, Ni, and Mo, and is attached to one or both sides of the steel plate 1. 3 is various micro-encapsulated fine particles. Microencapsulated corrosion inhibiting particulates are
Slightly soluble chromate fine particles (PbCrO ₄ , SrCrO ₄ ,
BaCrO ₄ , ZnCrO ₄ etc.), easily soluble chromates (CrO ₃ , Na ₂ CrO ₄ , K ₂ CrO ₄ , K ₂ O・4ZnO・
4CrO ₃ , etc.), aluminum compounds (Zn, Al alloy powder,
Al ₂ O ₃・2SiO ₂・2H ₂ O, etc.), phosphates (Zn ₃
(PO ₄ ) ₂・2H ₂ O, etc.), molybdenum compounds (ZnO・
ZnMoO ₄ , CaMoO ₄・ZnMoO ₄ , PbCrO ₄・
PbMoO ₄ , PbSO _4, etc.), titanium compounds (TiO ₂ ,
The particles may be either inorganic particles such as NiO.Sb 2 O 3 (NiO, Sb ₂ O _3, etc.) or organic particles such as fluororesin or polypropylene resin. The ultrathin film that microcapsulates the fine particles described above can be made of one or more inorganic substances such as SiO ₂ , TiO ₂ , AL ₂ O ₃ , ZrO ₂ , ethyl cellulose, amino resin, vinylidene chloride resin, polyethylene, polyethylene It consists of organic substances such as The film thickness is
The thickness is preferably 10 Å to 1 μ (preferably 10 Å to 500 Å). When the film thickness exceeds 1μ, the properties of the thin film material become noticeable (for example, SiO ₂ tends to cause particle agglomeration), resulting in a slight deterioration in plating performance, and conversely, when it becomes thinner than 10Å, coverage deteriorates. Therefore, the effect of suppressing particle dissolution tends to decrease. By microencapsulating particles, the following effects occur. The fine particles themselves have zero surface potential or are only slightly charged in the plating bath, so in electroplating methods that use electrophoresis, sufficient dispersion and co-deposition into the plating layer is ensured. Can not. However, ultrathin films such as SiO ₂ , TiO ₂ , Al ₂ O ₃ , ZrO _{2 ,} etc. have potential by themselves, and this property does not change even when coated on the surface of fine particles. It is possible to give a potential to Therefore, it is possible to improve the amount of dispersion of fine particles into the plating layer. Two advantages of microencapsulation are that it suppresses dissolution of microparticles in the plating bath. For example, slightly soluble chromate fine particles dissolve in a plating bath and release Cr ⁶⁺ ions, albeit in a small amount. this
When the concentration of Cr ⁶⁺ ions exceeds a certain level, the amount of released fine particles decreases, the appearance of the plating becomes black and powdery, and the adhesion of the plating deteriorates. Therefore, microencapsulation suppresses the dissolution of fine particles and makes it possible to obtain a laminated steel sheet that is stable for a long time. The third advantage of microencapsulation is that it improves corrosion resistance compared to dispersion eutectoid of only fine particles. The reason for this is thought to be that the corrosion inhibiting properties of the fine particles remain effective even after microencapsulation. The corrosion inhibiting effect of dispersed fine particles and microencapsulated fine particles will be described in detail. The reason why the corrosion resistance of the plating layer is improved by dispersing and eutectoiding the fine particles in the plating layer is considered to be as follows. When sparingly soluble chromate fine particles are dispersed and eutectoid, they decompose in a corrosive environment as the corrosion of the plating layer progresses, releasing Cr ⁶⁺ ions. This Cr ⁶⁺ ion reacts with the plating layer metal,
Forms chromium compounds, chromium oxides, or hydroxides with excellent corrosion resistance. This improves high corrosion resistance. Furthermore, even if this chromium compound layer is destroyed, since the fine particles are uniformly dispersed throughout the plating layer, the above formation reaction is repeated again, and corrosion resistance is maintained. Next, when microencapsulated fine particles are used, corrosion resistance is further improved. The film of SiO ₂ etc. produced by micro-encapsulation is not completely sealed and is porous, so Cr ⁶⁺ ions are eluted little by little, forming a rust-preventing film of chromium compounds and improving corrosion resistance. is the same as that of non-encapsulated particles. However, in the case of microencapsulated sparingly soluble chromate particles, compared to non-encapsulated sparingly soluble chromate particles,
By suppressing the elution rate of Cr ⁶⁺ ions (according to experiments conducted by the inventors, the rate is 1/3 to 1/10), a major feature is that the lifespan of rust-preventing film formation is extended accordingly. As mentioned above, the long-term perforation-resistant life of anticorrosive steel sheets for automobiles is targeted at 10 years, and the accelerated corrosion tests carried out in experiments also last for 1 to 3 months. Therefore, the dispersed particles in the plating layer temporarily become Cr ⁶⁺
Rather than releasing ions to form a thick anti-corrosion film made of chromium compounds, gradually releasing Cr ⁶⁺ ions to repeatedly form thin anti-rust films provides longer-term corrosion protection. As a representative example, we have described the anticorrosion effect of Cr ⁶⁺ ions eluted from poorly soluble chromate fine particles, but we have also discussed PO ₄ ^3- ions eluted from phosphate chlorides and MoO ₄ ^2- ions eluted from molybdenum compounds. The effect is the same. In other words, they release ions that have an anticorrosion effect. In addition, organic particles such as aluminum compounds, titanium compounds, and fluororesins have anticorrosion properties in themselves, and have the effect of acting as a corrosion inhibiting layer that exhibits a barrier effect against corrosion factors. According to experiments conducted by the inventors, the content of microencapsulated fine particles is preferably 0.1 to 30 wt% of the plating amount (preferably 0.5 to 30 wt%).
20wt% is good). If it is less than 0.1%, the effect on improving corrosion resistance is small, and if it exceeds 30%, the plating adhesion tends to deteriorate. Although the composite plated layer thus obtained exhibits sufficient rust resistance and porosity resistance as described above, it may inhibit the film crystallization of the chemical conversion treatment performed as a pre-painting treatment. For example, a composite plating layer containing microencapsulated poorly soluble chromate fine particles retains the properties of fine particles because the film is not completely sealed and is porous even if it is encapsulated. Phosphate treatment, which is carried out as a chemical conversion treatment, does not react on chromium, so it may cause the film crystals to become coarser or to cause scratches (crystals are not formed), which may cause variations in paint adhesion after painting and porosity resistance after painting. It becomes a factor that occurs. Therefore, when painting automobile exterior panels, etc., it is effective to apply an electric thinning layer of 1 to 5 g/m ² on the composite plating layer as shown in Figure 2b. be. If this electroplated layer is less than 1 g/m ² , it will be difficult to completely cover the composite plating layer, and if it exceeds 5 g/m ² , the adhesion to the plated surface will tend to deteriorate slightly. It is better to control within the above range. This electroplated layer consists of Zn, Fe,
Multi-layer plating treatment may be performed, consisting of one or more of Co, Mn, and Cr. However, in that case, the total adhesion amount is controlled at 1 to 5 g/m ² for the same reason as above. In addition, if chemical conversion treatment is not performed, as shown in Figure 2 c and d, either an organic resin film or an organic resin film containing chromium ions is applied as a composite plating layer or an electrically thin layer after organic resin or chromate treatment. By applying it on top of the coating layer, it is possible to ensure paint adhesion and puncture resistance after painting. This effect is due to the fact that the material of the capsule enclosing the corrosion-inhibiting fine particles is an inorganic or organic substance such as SiO ₂ or TiO ₂ , so the bonding property (- It is thought that chemical bonds such as O...H are generated) become stronger. The adhesion between the resin film and the paint is good, and the adhesion of the resin-coated composite plated steel sheet to the paint is also good. Furthermore, in order to improve corrosion resistance, it is also possible to perform chromate treatment on the composite plating layer. However, with chromate treatment alone, there is a concern that chromium (particularly Cr ⁶⁺ ions) in the chromate film may be leached out during the degreasing and chemical conversion treatment steps in the automobile production process. Since the elution of chromium is a major social problem in terms of pollution and hygiene, it is necessary to suppress the elution to almost zero. It is known that there are differences in chromium elution depending on the chromate method (high elution ← coated chromate > reactive chromate > electrolytic chromate → small elution), but corrosion resistance is in the opposite order of elution. Therefore, it is necessary to use them properly depending on the required corrosion resistance performance, etc. However, in any chromate treatment, chromium elution occurs, so it is necessary to cover with resin coating after the chromate treatment. It is also possible to prevent chromium from elution by incorporating chromium into a resin paint and applying the paint onto a steel plate and baking it to fix the chromium in the resin. Here, the organic resins include epoxy resins, epoxyphenol resins, water-soluble acrylic emulsion resins, etc., and the coating methods include roll coating,
Either electrostatic atomization method, curtain flow method, etc. may be used. At that time, the resin liquid composition has a resin content of 5 to 50% by weight.
If chromium is contained, one containing 1 to 20% by weight of chromium ions based on the resin content is used. However, if the film thickness is less than 0.1μ, the ability to prevent the elution of chromium in chromate will be significantly reduced, and if it exceeds 2μ, welding becomes difficult, so it is desirable to control it within the range of 0.1 to 2μ. Next, the present invention will be explained based on examples. Cold-rolled steel sheets were degreased with alkali, pickled with 10% sulfuric acid, washed with water, and subjected to electric composite plating under the following conditions. While circulating the liquid with a plating tabletop pump, the amount of various fine particles added to the plating bath can be changed to
The electrolytic treatment was carried out in a sulfuric acid acidic zinc or zinc alloy plating bath with pH=2, using a steel plate as a cathode. For example, in the case of Zn-Co-BaCrO ₄ (SiO ₂ thin film coated particles) composite plating, ZnSO ₄ 7H ₂ O 180 g / CoSo ₄ 7H ₂ O 10-450 g / BaCrO ₄ 5-60 g / (SiO ₂ thin film coated particles) pH=2.0, Bath temperature=50℃ Current density 40A/dm ² Electrolysis time 22sec Total deposition amount (target) 22g/m ² (Here, the coating material of the particles (e.g. SiO ₂ ) (The film thickness was 10 Å to 1 μ as appropriate.) Next, for thin electroplating on top of composite plating, Fe, Co, Ni,
Using a tacking bath in which appropriate amounts of Mn and Cr sulfates were added (no addition was made in the case of Zn plating), the total adhesion amount was in the range of 1 to 5 g/m ² . Further, the resin coating and the resin coating containing chromium were performed by a roll coating method using a water-soluble acrylic emulsion system as the resin. Also,
Chromate-treated resin coating was performed by roll coating, and chromate was applied by coating, reaction, or electrolysis. The following performance evaluation tests were conducted on the various composite plated steel sheets of the present invention manufactured in this manner. (1) Corrosion resistance Treatment: Unpainted and painted materials (Full-dip chemical conversion treatment → cationic electrodeposition coating → scratch damage) Evaluation: Measurement of red rust incidence and corrosion depth after 50 cycles of combined corrosion test (CCT) (Note) CCT: Salt spray (35℃ x 6Hr), dry (70℃, 60% x 4Hr), wet (49℃, >95%
Composite corrosion test (2) Paint adhesion Treatment: Full-dip chemical conversion treatment → 3-coat painting → Hot water immersion (40℃× (10 days) Evaluation: After the test, 100 squares of 2 mm squares were placed, and the rate of paint film peeling was measured by taping (3) The rate of occurrence of red rust was evaluated as follows. ◎...Red rust occurrence rate 0% ○...Red rust occurrence rate 5% or less △...Red rust occurrence rate 5-20% ×...Red rust occurrence rate 20-50% ××...Red rust occurrence rate 50% or more (4) Evaluation of corrosion depth is as follows. ◎...Corrosion depth 0mm ○...Corrosion depth 0.1mm or less△...Corrosion depth 0.1~0.3mm ×...Corrosion depth 0.3~0.5mm ××...Corrosion depth 0.5mm or more (5) Evaluation of paint adhesion It looks like this: ◎... Paint film peeling rate 0% ○... Paint film peeling rate 5% or less △... Paint film peeling rate 5-20% ×... Paint film peeling rate 20-50% ××... Paint film peeling rate 50% or more Table 1 shows the evaluation results. As is clear from this, it is clearly seen that the composite plated steel plate of the present invention is a highly corrosion-resistant composite plated steel plate with superior performance compared to comparative materials.

【table】

【table】

[Table] 〓〓〓 in component 4 means a multilayer structure.
(Effect of the invention) By using corrosion-inhibiting fine particles whose surface is coated with a thin film such as SiO ₂ , dissolution of the fine particles is suppressed, and the corrosion-inhibiting ability of the fine particles can be maintained for a long period of time. It has superior performance in comparison. Furthermore, by coating the surface with an easily soluble compound, it becomes possible to disperse and precipitate the compound into the plating layer. The present invention provides a highly corrosion-resistant zinc or zinc alloy electrolytically composite plated steel sheet in which fine particles having the above properties are dispersed and eutectoided in the plated layer.

[Brief explanation of drawings]

FIG. 1 shows the corrosion depth results of the composite plated steel plate of the present invention and a comparative material, and FIG. 2 shows a cross-sectional view of the composite plated steel plate model of the present invention.

Claims (1)

[Scope of Claims] 1 Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions having an anticorrosion effect in the plating layer, a compound that itself has corrosion-inhibiting ability, or both, are formed by SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb, Pb, Ni, Mo
A highly corrosion-resistant electrical composite plated steel sheet, characterized in that it has an alloy plating layer consisting of one or more of the following on one or both sides of the steel sheet. 2 Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions that have an anticorrosion effect in the plating layer, a compound that itself has corrosion-inhibiting ability, or both, are mixed with SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb, Pb, Ni, Mo
An alloy plating layer consisting of one or more types of
Highly corrosion-resistant electro-composite plating characterized by having a multi-layer electroplated layer made of one or more of Zn, Fe, Co, Ni, Mn, and Cr on one or both sides of a steel sheet. steel plate. 3 Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions that have an anticorrosion effect in the plating layer, a compound that itself has corrosion-inhibiting ability, or both, are mixed with SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb, Pb, Ni, Mo
1. A highly corrosion-resistant electrically composite plated steel sheet comprising a laminated layer comprising one or more alloy plating layers and a resin coating film on one or both sides of the steel sheet. 4 Corrosion-inhibiting fine particles consisting of a compound that forms corrosion products by releasing ions having an anti-corrosion effect in the plating layer, a compound that itself has corrosion-inhibiting ability, or both, are mixed with SiO ₂ ,
Containing a capsule coated with an ultra-thin film made of one or more of Al ₂ O ₃ , ZrO ₂ , TiO ₂ or a capsule coated with an ultra-thin film made of an organic polymer having film-forming ability, Galvanized layer or zinc and Co, Mn, Cr, Sn, Sb, Pb, Ni, Mo
An alloy plating layer consisting of one or more types of
It is characterized by having an electroplated layer made of one or more of Fe, Co, Ni, Mn, and Cr, and a resin coating film laminated thereon on one or both sides of the steel plate. Highly corrosion resistant electrical composite galvanized steel sheet.