JPH05253540A - Organic film coated zn base alloy plated al alloy plate - Google Patents

Abstract

PURPOSE:To provide an org. film coated Zn base alloy plated Al alloy plate excellent in outer surface rust-proof properties and lubricating properties after the plating and org-film coating of an Al alloy plate. CONSTITUTION:A Zn base alloy plating layer is applied to the single surface or both surfaces of an Al alloy plate in an amount of 0.1-60g/m<2> and an org. film containing 5-70wt.% of MoS2 particles with a mean particle size of 0.5mum or less is applied to the plating layer through a zinc phosphate film whose adhesion amount is 0.1-5g/m<2> in a thickness of 0.01-0.5mum to obtain an org. film coated Zn base alloy plated Al alloy plate.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an organic coated Zn-based alloy plated Al alloy plate, and more specifically, it has excellent corrosion resistance and lubricity, weldability, and electrodeposition paintability, and has various uses, for example, The present invention relates to an organic coating Zn-based alloy plated Al alloy plate applicable as an Al alloy plate for automobiles.

[0002]

2. Description of the Related Art In general, steel sheets for automobiles undergo various processes in the process of car body manufacturing, and therefore lubricity for pressing, weldability for joining parts, and electrodeposition paintability during painting are essential. It On the other hand, corrosion resistance is particularly required in the traveling environment of automobiles. From the viewpoint of corrosion resistance, not only bare corrosion resistance but also external surface rust resistance, perforation resistance, hot water immersion adhesion of coating film, red rust resistance and the like are required. For example, Japanese Patent Publication No.
Zn-Ni plated steel sheet seen in Japanese Patent Publication No. 29821, Zn-Fe2 seen in Japanese Patent Publication No. 56-133488.
The plated steel sheets that have been conventionally used such as the layer-plated steel sheet have excellent corrosion resistance, but there is no example in which such a plating is coated on the Al alloy sheet. Furthermore, the performance required from the user side is higher. However, there is room for improvement in the plating to be coated in terms of outer surface rust resistance and perforation resistance of processed parts. Further, a single-layer plated composite plated steel sheet found in Japanese Patent Publication No. Sho 58-247984 has been proposed, but its application to an Al alloy sheet is partially found in Japanese Patent Laid-Open No. 61-157693, but it is resistant to yarn rust. At present, it is not sufficient in terms of lubricity and lubricity.

[0003]

In view of the above situation, the inventors of the present invention have conducted various experiments, and as a result, the surface of an Al alloy plate has been subjected to Zn-based alloy plating and, as an upper layer, zinc phosphate treatment. It was found that by adding an organic coating film containing MoS ₂ to the Al alloy plate, the outer surface rust resistance and lubricity are improved without impairing the weldability and electrodeposition coatability. It is considered that the Zn-based alloy plating and the zinc phosphate coating coated on the Al alloy plate suppressed the thread rust peculiar to the Al alloy plate and improved the outer surface rust resistance. It was also found that the lubricity is remarkably improved by thinly applying an organic coating film containing MoS ₂ on the zinc phosphate coating.

The present invention has been made on the basis of the above findings, and the gist thereof is as follows: (1) The amount of plating deposited as an underlayer is 0.1 to 60 g on one or both sides of an Al alloy plate. / M ² Zn-based alloy plating layer, and MoS ₂ having an average particle size of 0.5 μm or less is added to the upper layer through a zinc phosphate coating having an adhesion amount of 0.1 to 5 g / m ^2.
An organic coating Zn-based alloy plated Al alloy plate having an organic coating film containing 70 wt% of 0.01 to 0.5 μm. (2) The Zn-based alloy plating of the lower layer is Fe, Ni, C
1 to 90 wt% of one or more alloy elements selected from o, Cr, Al, and Mn are contained in the organic coated Zn-based alloy plated Al alloy plate of (1).

The present invention will be described in detail below. First, in the present invention, the organic coated Zn-based alloy-plated Al alloy plate is composed of three layers including a Zn-based alloy plating, a zinc phosphate coating, and an organic coating film containing MoS ₂ as an upper layer as described below. The reason why this has a three-layer structure is that the outer surface rust resistance, lubricity, weldability, and electrodeposition paintability are taken into consideration at the same time, as described above. Here, the Zn-based alloy plating of the lower layer refers to a Zn-based alloy plating containing one or more alloy elements selected from Fe, Ni, Co, Cr, Al, and Mn. Rate is 1-9
It is 0%. The reason for using these platings is that Al or F
While e tends to cause thread rust, Zn-alloy plating generally does not show thread rust and has better corrosion resistance than Zn single plating, and therefore has an excellent effect of suppressing rust width. Therefore, by coating the Zn alloy plating on the Al alloy plate,
Effective for improving outer surface rust resistance. Further, Zn-based alloy plating generally has a higher surface hardness than Zn single plating, and the friction coefficient tends to decrease. This effect is remarkable as compared with the original aluminum alloy plate. In addition, the lower limit of the alloy element content is 1% at which improvement in corrosion resistance is recognized as compared with Zn single plating,
On the other hand, if it exceeds 90%, the alloy plating layer becomes too hard and the lubricity deteriorates, so this was made the upper limit.

The role of the zinc phosphate film under the three-layer structure is important from the viewpoint of improving the adhesion between the plating and the organic coating film. The reason why the zinc phosphate coating amount is limited to 0.1 to 5 g / m ² is that the adhesion between the plating and the organic coating is not good outside this range. It can be said that these are known functions when considering the organic composite plated steel sheets developed so far. Furthermore, by applying a thin MoS ₂ -containing organic coating film to the uppermost layer, it is possible to improve the lubricity without impairing the weldability and electrodeposition coating property.

Here, the constitution and role of the organic coating film are explained.
Reveal MoS in the coating₂Is mainly used for electrodeposition
The purpose is to improve paintability during painting.
oS ₂Uses that it shows semiconductivity depending on conditions
Of. MoS with an average particle size of 0.5 μm or less in the coating film₂
The coating film containing 5 to 70 wt% has a thickness of 0 to 20 μm.
In the range, good electrodeposition coatability is exhibited. If necessary,
Conductive fine particles may also be used in combination. Examples of conductive particles
As for zinc oxide, tin oxide, conductive carbon, graph
And iron tetroxide. Contained as the amount to be used in combination
MoS₂Is preferably 0 to 50 wt% of the content of
5 to 20 wt% is desirable. MoS₂Increase the amount of
The energizing amount increases as the
The electrodeposition limit film thickness also increases, but if it exceeds 70 wt%, corrosion resistance
Cause a decrease in sex. As a resin to disperse these
As long as it is a resin generally used in coating compositions, there are no particular restrictions.
Absent. In addition, colloidal silica, flow regulator and coloring
Pigment, anti-foaming agent, dispersant, anti-settling agent, blocking
Do not cover pigment additives used in general paint such as inhibitors.
It can be used as long as the characteristics of the covering are not impaired.

Although MoS ₂ is generally known as a solid lubricant, the same effect was observed in the coating film. The reason why the average particle size of MoS ₂ is limited to 0.5 μm or less is that the particle size of 0.5 μm or more is not preferable in appearance and causes workability defects such as mold galling, and is preferably less than the coating film thickness. To do. The MoS ₂ -containing organic coating film had a coating thickness of 0.01 μm or more and was found to have very good lubricating properties. Furthermore, since the upper coating film of the organic coating Zn-based alloy-plated Al alloy plate of the present invention has a very small current at a low voltage, it exhibits good corrosion resistance and good electrodeposition coating property. Good weldability is essential for determining the effective range of the coating thickness. Of the weldability, the continuous spotting property is particularly important, but an increase in the coating thickness leads to a decrease in the continuous spotting property. When the thickness of the upper coating film of the present invention exceeds 0.5 μm, the spotting property is remarkably lowered. Therefore, the upper layer film thickness is set to 0.5 μm or less.
Hereinafter, the effects of the present invention will be described more specifically with reference to Examples.

[0009]

EXAMPLES The production of the plated Al alloy plate of the present invention was conducted at pH 1
˜3 fluoride bath or pH 13.5-14.5 alkaline bath and pH 1-3 sulphate bath,
It is possible by performing electroplating using a chloride bath.
However, in the examples shown below, the electroplating conditions are a current density of 10 to 200 A / dm ² and a line speed of 10
˜250 m / min. The base Al alloy plate was mainly based on 5000 series and 6000 series. Ordinary immersion type zinc phosphate treatment (coating amount 0.1-10
g / m ² ) was applied. For organic coating, the following coating composition was applied with a bar coater.

(1) MoS _{2 having} an average particle diameter of 0.5 μm or less (manufactured by Moly Powder PA Sumiko Lubricant) (2) SiO ₂ (manufactured by Mizukasil P-526 Mizusawa Chemical) (3) Phenoxy resin (ESRP #
250 20% liquid manufactured by Sumitomo Chemical Co., Ltd.) (4) Butylcellosolve (5) Methylethylketone (6) Dispersant However, the compounding ratio was appropriately changed with changes in film thickness and MoS ₂ content.

The evaluation tests include flat plate pull-out test (friction coefficient measurement), yarn rust resistance test (thread rust occurrence), continuous spotting property test (spotting number, dust occurrence), electrodeposition paintability test (surface smoothness appearance observation). I went. The test conditions are shown below. [Plate drawing test condition] Specimen size: 1.0 mm x 30 mm x 300 mm Pressing force: 450 kgf Drawing speed: 200 mm / min Tool contact area: 900 mm ² (30 mm x 30 mm)

[Test Conditions for Thread Rust Resistance] Specimen size: 1.0 mm × 70 mm × 150 mm Sample preparation: A plating aluminum plate was subjected to chemical conversion treatment + 3 coats, and then scratches reaching the base of coating were added. Test environment: salt spray + wet environment.

[Conditions for continuous spotting test] Electrode: Tip C type 4.5 mmφ Pressurization: Based on 200 kgf Energization time: 10 cycles Energization condition: Use of proper welding current Measurement of nugget diameter and dust by peel test as evaluation of number of spots The occurrence is observed and judged.

[Conditions for Electrodeposition Coating Property Test] Species: Epoxy-based cation type electrodeposition coating type Electrodeposition conditions: 200V, 3min Baking conditions: 180c, 30min Coating thickness: 20 ± 2 μm Further, the evaluation criteria of each test are as follows. Is the street.

[0015]

[0016] However, thread rust occurs from the cut scratches.

[0017]

[0018]

In the present invention, the lower layer is made of Zn--Fe (10-5).
0%), Zn-Cr (5-30%), Zn-Mn (1-
50%), Zn-Fe (1 to 15%)-Al (10 to 3)
0%), Zn-Ni (1-30%)-Cr (5-10)
%), Zn-Al (1 to 80%) Zn-based alloy plating is applied at an adhesion amount of 10 g / m ² respectively, and the upper organic film is M
The relationship between the amount of zinc phosphate coating and the adhesiveness of the organic coating when the content of oS ₂ is 20 wt% and the thickness is 0.5 μm is shown in Table 1 and FIG. 1, the lower layer is Zn—Co (20 to 50%). , Z
n-Ni (1-40%), Zn-Fe (1-50%)-
Co (1-5%) Zn-based alloy plating is applied,
The amount of zinc phosphate deposited is 2 g / m ² , and the upper organic film is Mo.
Table 2 and FIG. 2 show the relationship between the Zn-based alloy plating deposition amount and each evaluation test in the case of containing S ₂ of 20 wt% and having a thickness of 0.5 μm. Zn-
Al (1-70%), Zn-Fe (5-85%)-Cr
(1 to 5%) and Zn-Ni (1 to 90%) Zn-based alloy plating is applied at an adhesion amount of 1 g / m ² , respectively, and zinc phosphate adhesion amount is 2 g / m ² , and an organic layer containing MoS ₂ in the upper layer. The relationship between the MoS ₂ content in the organic film and each evaluation test when the film thickness is 0.5 μm is shown in Table 3 and FIG.
e (1-90%), Zn-Al (1-70%), Zn-
Fe (5-85%)-Cr (1-5%), Zn-Ni
(1 to 90%) Zn-based alloy plating applied 1 each
Table 4 and FIG. 4 show the relationship between the organic coating thickness and the evaluation test in the case where 0 g / m ^{2 was} applied, the amount of zinc phosphate deposited was 2 g / m ² , and the upper organic coating contained 20 wt% MoS ₂ . The symbols on the vertical axis of (wet), (melt), (rust), and (electric) in the figure represent lubricity, continuous dot-forming property, yarn rust resistance, and electrodeposition coating property, respectively.

From FIG. 1, the zinc phosphate coating amount is 0.1 to 5 g.
It can be seen that the adhesion of the organic film is good in the range of / m ² . From FIG. 2, it can be seen that the occurrence of thread rust is not observed when the Zn-based alloy plating is 0.1 g / m ² or more, and the continuous dot-forming property is deteriorated when it exceeds 60 g / m ² . From FIG. 3, the content of MoS ₂ is 5 to 70 due to the limitation of the electrodeposition coatability.
It is considered appropriate to set it as wt%. From FIG. 4, the lower limit of the organic film thickness is 0.01 μm because of lubricity, and the upper limit is 0.5 μm because of weldability, and this range is a suitable film thickness. From the above, the Zn-based alloy plating layer was 0.1
~ 60g / m ² coating, the amount of adhesion to the upper layer 0.1-5g / m
M with an average particle size of 0.5 μm or less through the zinc phosphate coating of ²
An organic film containing ₅ to 70 wt% of oS ₂ is 0.01 to
It was confirmed that the structure of 0.5 μm is suitable for improving the lubricity and the outer surface rust resistance of the Al alloy plate.

[0021]

[Table 1]

[0022]

[Table 2]

[0023]

[Table 3]

[0024]

[Table 4]

[0025]

As described above, according to the present invention, there is an organic coated Zn-based alloy-plated Al alloy plate which is extremely excellent in external surface rust resistance and lubricity after plating of the Al alloy plate and coating of an organic film. The industrial significance is that it can be applied as an Al alloy plate for automobiles.

[Brief description of drawings]

FIG. 1 is a diagram showing the relationship between the zinc phosphate coating amount and the organic coating adhesion according to the present invention.

FIG. 2 is a diagram showing a relationship between a Zn plating deposition amount and each evaluation test according to the present invention.

FIG. 3 is a diagram showing the relationship between the MoS ₂ content in the organic film according to the present invention and each evaluation test.

FIG. 4 is a diagram showing the relationship between the organic film thickness and each evaluation test according to the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification number Office reference number FI Technical indication location C23C 28/00 B C25D 5/30 (72) Inventor Kazuhiko Honda 20-1 Shintomi, Futtsu-shi, Chiba Shin Nippon Steel Co., Ltd.

Claims (2)

[Claims] 1. An Al alloy plate has a Zn-based alloy plating layer having a coating amount of 0.1 to 60 g / m ² as a lower layer on one or both sides, and an upper layer having a coating amount of 0.1 to 5 g / m ² . MoS _{2 with} an average particle size of 0.5 μm or less through a zinc phosphate coating
An organic coating containing 5 to 70 wt% of 0.01 to 0.5
An organic coating Zn-based alloy plated Al alloy plate having a thickness of μm. 2. The Zn-based alloy plating of the lower layer is Fe, N
The organic-coated Zn-based alloy-plated Al alloy plate according to claim 1, which contains 1 to 90 wt% of one or more alloy elements selected from i, Co, Cr, Al, and Mn.