JPH0688208A - Highly corrosion resistant surface treated metallic material and its production - Google Patents

Abstract

PURPOSE:To produce the surface treated metallic sheet, such as steel sheet, having excellent corrosion resistance and formability by laminating vapor deposited plating layers of an Al-Ti alloy and pure Al having specific quality on both surfaces of the metallic sheet. CONSTITUTION:The metallic sheet 1, such as steel sheet, is introduced through an inlet side vacuum sealing device 2a into a vacuum vapor deposition chamber 4a and is passed above a vapor deposition chamber 6a contg. the Al-Ti alloy 6 consisting of 1 to 30% Ti and the balance Al and a vapor deposition chamber 5b contg. the pure Al 6b. The Al-Ti alloy 6a is evaporated by using a high-energy beam, such as electron beam to form the vapor deposited plating layer of the Al-Ti alloy on one surface of the steel sheet; in succession, the pure Al 6b is evaporated by the electron beam thereon to form the vapor deposited Al layer. These vapor deposited layers are so formed that the ratio of [Al]/[Al-Ti] attains 1/5<=R<=1 when the deposition of the vapor deposited Al layer is expressed as [Al]g/m<2> and the deposition of the vapor deposited Al-Ti alloy layer as [Al-Ti]g/m<2>. The Al-Ti alloy layer and the vapor deposited pure Al layer having the similar compsns. are similarly formed on the opposite surface of the steel sheet in a vacuum vapor deposition chamber 4b.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vapor-deposited surface-treated metal material having excellent corrosion resistance, which is used for building materials, home electric appliances, containers, automobiles and the like, and a method for producing the same.

[0002]

2. Description of the Related Art Al and Al alloys (sometimes referred to as "Al alloys" below) are more commonly used in building materials and containers because of their superior corrosion resistance compared to steel and their cleanliness. Products plated on steel sheets have also been put to practical use.

[0003] Above all, since the production cost of Al plated steel sheet is relatively low, the excellent oxidation resistance, corrosion resistance and heat resistance of Al are utilized to make automobile mufflers, household appliances, building materials, garbage incinerators, etc. It is widely used as a member used under severe conditions.

[0004] However Al plating steel Cl ^- A by the ion in the presence environment in which the anions such as
l The passive oxide film on the plating surface is destroyed, white rust mainly composed of Al (OH) ₃ is generated on the Al plating surface, and pitting corrosion is generated, especially in the case of Al-plated steel material. Further, pitting corrosion may progress and even the base steel sheet may be corroded, resulting in red rust.

By the way, since the Al-plated metal material has been conventionally manufactured mainly by a hot dip plating method, in order to improve the above-mentioned defects of the Al-plated metal material and to improve the corrosion resistance, A
The addition of an alloying element such as Zn to the 1-bath has been studied. However, in the current hot dip plating method, the elements that can be dissolved in the Al bath and the amount thereof are limited, and therefore, those having sufficient corrosion resistance have not been obtained.

Further, in the hot dipping method, the process of supplying and passing the metal material into the molten Al is indispensable, so the surface temperature of the metal material rises up to about 700 ° C. For example, in the case of an Al plated steel sheet, the interface between the steel sheet and the Al plating. An Fe-Al intermetallic compound such as Fe ₂ Al ₅ is generated at. The intermetallic compound is brittle and causes peeling of the plating during molding, resulting in poor workability.

Therefore, in order to suppress the formation of Fe-Al intermetallic compounds and the like that occur at the interface between the plating and the base metal, Si is added to the molten Al bath in an amount of about 10%, and Fe during plating is added.
-Al intermetallic compound production is suppressed and the Fe-Al intermetallic compound formation (heat resistance) is also suppressed at high temperatures, especially when used at 400 ° C or higher, but this is not always sufficient. . Moreover, when Si is added, the corrosion resistance of the Al plating itself is rather lowered. Therefore, in an Al-plated steel sheet to which Si is added as an alloying element, a thin protective coating is often formed on the plated surface by chemical conversion treatment such as chromate treatment in order to supplement the corrosion resistance of Al plating. However, once this protective film is destroyed or disappears due to corrosion or the like, corrosion of the Si-added Al plating layer having insufficient corrosion resistance occurs, so it cannot be said to have a sufficient effect of improving corrosion resistance.

As described above, none of the Al-based hot-dip galvanized metal materials satisfy all of the required characteristics, and the hot-dip galvanizing method has a drawback that it is not possible to manufacture a galvanized steel sheet by the manufacturing method.

Another plating method is an electroplating method, which is often used for Zn plating. In the plating method, Al or Al from an aqueous solution is used.
Electrodeposition of metal alloys is not possible, and electroplating from a non-aqueous solution is possible in principle, but the current density at the time of electrodeposition is very small, so plating efficiency is low, and the plating solution Even considering the electrical instability, it is difficult to apply the electroplating method to industrial production.

[0010]

In order to deal with such a situation, recently, development of dry Al plating technology by a vacuum vapor deposition method has been advanced. Therefore, the present inventors intend to establish a vacuum method to establish a method of producing a surface-treated steel sheet that simultaneously satisfies the problems of a typical Al-plated steel sheet among Al-plated metal materials, that is, heat resistance, corrosion resistance, and formability. When the vapor deposition plating method was examined, and the surface of the steel sheet was first subjected to pure Al plating by the vacuum vapor deposition method, the following problems were confirmed. That is, even the Al vapor-deposited steel sheet has the same corrosion resistance as the hot-dip Al-plated steel sheet, and does not show any effect of improving the corrosion resistance against the attack of halogen ions or the like.

The present invention has been made in view of these circumstances, and basically, while utilizing the characteristics of the Al-plated metal material that is economical and excellent in various characteristics, corrosion resistance,
An object of the present invention is to provide a surface-treated metal material which is more excellent in moldability and the like, and a method for producing the same.

[0012]

The highly-corrosion-resistant surface-treated metal material of the present invention which has been able to solve the above-mentioned problems has an Al-Ti alloy vapor deposition plating layer containing 1 to 30% of Ti on the surface of a metal base material. The gist is that it is formed and a pure Al vapor deposition plating layer is further formed thereon. Further, the adhesion amount of the Al vapor deposition plating layer is [Al] (g / m ² ), A
1-Ti alloy vapor deposition plating layer adhesion amount [Al-Ti]
When it is (g / m ² ), the adhesion ratio R represented by [Al] / [Al-Ti] is preferably in the range of 1/5 ≦ R ≦ 1.

Further, according to the manufacturing method of the present invention, when the metal base material is continuously vapor-deposited and plated, an Al--Ti alloy evaporation tank is provided in the vacuum vapor deposition chamber on the upstream side with respect to the traveling direction of the base metal, Al evaporation tanks are installed in parallel on the downstream side, and each evaporation tank is heated by a high-energy beam to generate Al-Ti mixed vapor and Al vapor, and the surface-cleaned metal substrate is vacuum-deposited. It has the gist of allowing it to run continuously through a room and performing vapor deposition Al / Al-Ti alloy-based two-layer plating on the metal surface.

[0014]

The kind of the metal material used as the base material in the present invention is not particularly limited, and general stainless steel materials, various stainless steel materials, alloy steel materials, and also Al and Al alloy materials, Cu
And Cu alloy materials, Ti and Ti alloy materials, and the like. Further, the shape thereof may be any shape such as plate shape, corrugated plate shape, rod shape, and linear shape as long as vapor deposition plating is possible. The following will describe the process of the present invention, but a cold rolled steel sheet, which is the most common metal material as a base material, will be described as a typical example.

The inventors of the present invention produced Al alloy-plated steel sheets to which various alloying metals were added by using the vacuum vapor deposition method and evaluated their corrosion resistance. As a result, the Al-Ti alloy vapor-deposited steel sheets are excellent in corrosion resistance. And filed a prior application (for example, Japanese Patent Laid-Open Nos. 64-28359, 1-96369, 1-18
4268, JP-A 1-259159, etc.).

Then, the present inventors examined the reason why the corrosion resistance of the vapor-deposited Al-Ti alloy plated steel sheet is excellent. The effect of Ti in the plated layer is that the plated layer is exposed in a corrosive environment in which chloride anions exist. It reduces the corrosion rate of itself, and the addition of Ti causes Al-T
The corrosion current density of the i alloy decreases, the pitting corrosion resistance of the Al-Ti alloy itself is improved, and the addition of Ti reduces the electrochemical potential difference between the plating layer and the base steel sheet, resulting in sacrificial corrosion resistance. It was found to be a combined effect of a decrease in current density.

In view of the excellent pitting corrosion resistance of the Al-Ti alloy plated layer, the progress of corrosion in the thickness direction of the plated layer due to pitting corrosion is suppressed, and as a result, the time of occurrence of red rust due to corrosion of the steel sheet is significantly extended. However, since the sacrificial anticorrosion current density is small, the sacrificial anticorrosion ability of the processed portion or the end face may be insufficient.

Therefore, the inventors of the present invention, on the basis of the knowledge on the above corrosion mechanism, vapor-deposited Al / Al-T having a pure Al plating layer as an upper layer and an Al-Ti alloy plating layer as a lower layer.
The present invention has been achieved by developing an i2-layer plated steel sheet.

First, the role of the Al-Ti alloy of the lower layer plays a role of excellent pore corrosion resistance in a corrosive environment in which chloride ions are present as described above. The Ti content in the lower plating layer needs to be 1 to 30%. If the Ti content is less than 1%, the effect of adding Ti to the plating layer will not be sufficiently exhibited, and pitting corrosion resistance will not be exhibited. If it is less than 1%, as described below, there is almost no electrochemical potential difference between the upper pure Al plating layer and the upper pure Al plating layer. It becomes difficult to suppress the progress of pitting corrosion in the depth direction. On the other hand, when the Ti content exceeds 30%, not only the pitting corrosion resistance is saturated, but also the cost at the time of plating production is increased, which is not preferable. For the above reasons, the Ti content in the lower Al-Ti plated layer is set to 1 to 3
The limit is set to 0%. Next, the reason why the upper layer is a pure Al plating layer and the lower layer is an Al-Ti alloy plating layer will be described from the viewpoint of the corrosion process of the plating layer of the present invention.

First, when the Al / Al-Ti alloy two-layer plating layer of the present invention is applied to the surface of the substrate, pitting corrosion is initially caused by pure A of the upper layer.
1. Starting from the surface of the plated layer (initial pitting corrosion process). Then, the pitting corrosion progresses along the plating thickness direction of the upper pure Al plating layer, and eventually reaches the interface with the lower Al / Al-Ti alloy plating layer (the pitting corrosion progress process of the upper layer plating. ).

By the way, there is a slight electrochemical potential difference between the upper pure Al plating layer and the lower Al-Ti alloy plating layer, and the Al-Ti alloy plating layer is smaller than the pure Al plating layer. , Has a slightly noble potential. Therefore, when the pitting corrosion reaches the interface between the upper pure Al plating and the lower Al-Ti plating, a galvanic corrosion phenomenon occurs between the plated layers due to the potential difference between the two. That is, the upper pure Al plating layer is selectively corroded by the galvanic phenomenon, which means that the upper pure Al plating layer is lower Al-Ti.
It means that the plating layer has a kind of sacrificial anticorrosion ability. The upper pure Al plating layer is corroded in the plating thickness direction at the initial pitting corrosion generation time and the pitting corrosion progressing time, but after the pitting corrosion reaches the interface of the upper layer plating / lower layer plating, the pitting corrosion is lower layer Al. -Instead of proceeding in the thickness direction of the Ti plating layer, the general corrosion of the upper Al plating layer starts instead (the general corrosion progress process of the upper plating). Since the general corrosion indicates a corrosion mode in which the plating thickness gradually decreases from the surface of the plating layer, this general corrosion causes the plating thickness of the upper pure Al plating layer to be extremely thin. , It continues until there is almost nothing (overall corrosion progress process of upper layer plating). In other words, the period during which this upper layer plating remains
It means that the lower layer Al-Ti plating layer is effectively protected by the upper layer plating, and the corrosion start time of the lower layer is
The presence of the upper plating layer will be significantly delayed.

After that, when the upper plating layer is almost completely eluted due to the general corrosion, the lower Al--Ti layer is then removed.
Corrosion (pitting corrosion) of the plating layer due to chloride ions is started (pitting corrosion starting process of the lower layer plating).
Since the Ti alloy plating layer itself is basically a plating layer having excellent pitting corrosion resistance, the pitting corrosion progresses very slowly in the plating depth (thickness) direction (lower layer plating pitting corrosion progressing process) The time required for pitting to reach the interface with the steel plate surface, which is the material, until red rust occurs becomes longer.

In this way, the upper pure Al plating layer and the lower Al-
Each of the Ti plating layers has a meaningful role, that is, the upper pure Al plating layer itself does not have excellent pitting corrosion resistance, but has a sacrificial anticorrosive ability of protecting the lower Al-Ti plating layer. Plays an important role as a plating layer, lower layer A
The 1-Ti plating layer plays a role as a plating layer having excellent pitting corrosion resistance that delays the corrosion period of the material to be plated after the upper layer plating disappears. Therefore, as a result of the synergistic effect of the roles of the upper and lower plating layers, the corrosion time of the steel sheet to be plated is significantly extended.

In the present invention, the upper layer must be a pure Al plating layer and the lower layer must be an Al-Ti plating layer. This is because when the upper layer is an Al-Ti plated layer and the lower layer is a pure Al plated layer (a structure opposite to the plated layer structure of the present invention), it particularly reaches the end face, the processed portion, or the steel plate surface. In places such as scratches in the plating layer, the pure Al of the lower layer is formed before the Al-Ti plating layer of the upper layer.
This is because the plating layer is preferentially corroded, and as a result, the blistering phenomenon and the peeling phenomenon of the upper plating layer occur and the high corrosion resistance is lost.

Next, the phase structure of the lower Al-Ti alloy plating layer will be described. It goes without saying that the lower Al-Ti alloy plating layer contains an Al-Ti intermetallic compound phase as an essential component. The Al-Ti intermetallic compound phase is
It has excellent pitting corrosion resistance to chloride ions, and the intermetallic compound phase must exist in the Al-Ti plating layer in order to serve as the lower layer as described above. The intermetallic compound formed in the Al-Ti plating layer is not limited to one kind, and may be, for example, Al depending on the manufacturing conditions and the Ti content in the plating layer.
One or more Al-Ti intermetallic compounds such as ₃ Ti, AlTi, and Al ₃ Ti are present. These Al-T
The i intermetallic compound phases are all excellent in pitting corrosion resistance, and in the present invention, it is specified that the intermetallic compound phase is necessarily contained in the lower plating layer. The Al ₃ Ti phase has better pitting corrosion resistance than other intermetallic compound phases, and at the same time, the electrochemical potential shows a more base potential than the potential of the steel sheet (however, the upper layer pure A
Since it is always nobler than the potential of 1-plating), the sacrificial anticorrosion effect on the steel sheet is excellent. Thus, as the Al-Ti intermetallic phase present in the lower Al-Ti-plated layer, and more preferably Al ₃ Ti phase.

Further, in addition to the above-mentioned various Al-Ti intermetallic compound phases being present in the lower Al-Ti plating layer, it is desirable that the lower Al-Ti plating layer contains an Al phase and / or a Ti phase as another component. . Al contained in the lower Al-Ti plating layer has two functions of an effect of improving plastic deformability of the lower plating layer and an effect of ensuring plating adhesion with the upper pure Al plating layer, It is possible to effectively suppress the peeling of the plating layer from the surface of the material to be plated or the interface between the upper / lower plating layers during processing.

T contained in the lower Al-Ti plating layer
i does not mean that all of them react with Al to form an Al-Ti intermetallic compound phase, and especially in the region where the Ti content is high within the range of the Ti content specified in the present invention, the lower layer It is highly possible that Ti is present in the plating layer. Ti in the lower plating layer is basically a metal that is not corroded by chloride ions, and when present in a trace amount in the lower plating layer, it contributes to improving the pitting corrosion resistance of the plating layer. is there. When the vapor-deposited Al / Al-Ti alloy double-layer plated steel sheet is used in a high-temperature environment (generally 500 ° C or higher), a small amount of Ti in the lower-layer plating is present at the interface between the lower-layer Al-Ti alloy plated layer and the steel sheet. It has a function of effectively suppressing the formation of the Al-Fe based intermetallic compound layer, and contributes to the improvement of the heat resistance of the plating layer.

Next, the reason for defining the ratio of the upper layer plating film thickness and the lower layer plating film thickness will be described. Pure Al coating layer coating weight of the upper layer (g / m ²⁾ the underlying Al-Ti alloy coating weight (g / m ²⁾ divided by the, i.e. a coating weight ratio when the R, 1/5 ≦ It is desirable to satisfy R ≦ 1. The lower limit of the ratio is defined as 1/5 for the following two reasons.

(1) First, the fact that R is less than 1/5 means that
This means a case in which the amount of pure Al plating deposited on the upper layer is significantly smaller than the amount of Al-Ti plating deposited on the lower layer when considering the entire plated layer. The main role of the upper pure Al plating layer is the sacrificial anticorrosion ability for the lower Al-Ti alloy plating layer, as described above. The pure Al plating layer itself is the lower Al-Ti layer.
Since it is inferior in pitting corrosion resistance to the alloy plating layer,
Although it has no ability to suppress pitting corrosion in the plating thickness direction,
The sacrificial anticorrosive action due to the general corrosion can effectively prevent the corrosion of the lower Al-Ti alloy plating layer. In order to exert such an effect as the upper layer plating, if the amount of the lower layer plated is less than 1/5, the period for exhibiting the sacrificial anticorrosion action is shortened, and the amount of the deposited layer is at least 1/5. Is desirable.

(2) Further, as an important role of the upper pure Al plating layer, there is a sacrificial anticorrosion ability for the plated material as a whole of the plating layer. As described above, the sacrificial anticorrosive ability of the plated layer with respect to the material to be plated is generally superior as the plated layer has a larger base potential with respect to the electrochemical potential of the material to be plated. By the way, it has already been described that the lower Al-Ti alloy plating layer has a slightly noble electrochemical potential as compared with the upper pure Al plating layer. Therefore, the potential difference between the lower Al-Ti alloy plating layer and the steel sheet is higher than that of the pure Al plating and the steel sheet. It becomes a little smaller than the potential difference between them. Therefore, if the potential difference becomes smaller, the sacrificial anticorrosion current decreases accordingly, and the corrosion rate (elution rate) of the plating layer itself becomes smaller and the life of the plating layer becomes longer, while the end surface (cut surface), The pure Al plating layer is superior in the sacrificial anticorrosive ability to the steel sheet at the processed portion or the scratched portion from the surface of the plating layer that reaches the surface of the steel sheet. Therefore,
The upper pure Al plating layer is required to exert a sacrificial anticorrosion effect on the steel plate as the material to be plated under an exposed environment such as an end surface. For that purpose, the plating adhesion ratio R defined above is 1 It is desirable to have an upper layer pure Al plating adhesion amount of / 5 or more.

The reason why the plating adhesion amount ratio R is specified to be 1 or less is as follows. When R exceeds 1, it means that the amount of deposited pure Al plating on the upper layer is larger than the amount of deposited Al-Ti plating on the lower layer when considering the entire plated layer. Two-layer plating with such a ratio is
Since the deposition amount ratio of the Al-Ti alloy plating layer having excellent pitting corrosion resistance of the lower layer is small, the performance as the original purpose of the high corrosion resistance plated material is deteriorated. Therefore, the lower layer Al
The upper limit of the coating weight ratio R was defined as 1 so as not to reduce the ratio of the Ti alloy coating weight.

The vapor-deposited Al / Al- obtained by the present invention.
The total coating amount of the Ti alloy two-layer plating is not limited in any way in the present invention, and should be appropriately determined depending on the member to which the surface treatment material of the present invention is applied, the environmental conditions to be used, the required service life, etc. Is desirable. Generally, considering both corrosion resistance and economy, 10-100 g /
A coating weight of m ² , preferably in the range of 20-60 g / m ² is recommended.

Next, the method for producing high corrosion resistance according to the present invention will be described with reference to FIG. The to-be-plated metal material 1 whose surface has been cleaned in advance by various methods is introduced into the No. 1 vapor deposition chamber 4a via the inlet vacuum seal device 2a. The vapor deposition chambers 4a and 4b are maintained in a desired vacuum or a dilute gas atmosphere. In the vapor deposition chambers 4a and 4b, two evaporation tanks 5a and 5b are arranged in parallel below the metal material to be plated, and the Al-Ti alloy bath 6a is provided in the evaporation tank 5a on the upstream side with respect to the traveling direction of the metal material. And an Al bath 6b is prepared in the evaporation tank 5b on the downstream side. Two melting baths 6a, 6
b is a metal to be plated which is heated by irradiation of an electron beam (not shown) generated from an electron gun (not shown) to generate Al-Ti mixed vapor and Al vapor from both evaporation tanks and which runs. Evaporated Al on the surface of material 1
/ Al-Ti alloy-based two-layer plating is applied. The metal material 1 to be plated, which has been vapor-deposited on only one surface in the No. 1 vapor deposition chamber, is introduced into the No. 2 vapor deposition chamber via the deflector roll 3, and the other process is performed in the same manner as the No. 1 vapor deposition chamber. The vapor deposition plating process is performed on one surface of the. The metal material 1 to be plated, which has been plated on both sides in this manner, is used as the output side vacuum seal device 2b.
After that, predetermined post-processing is performed.

The manufacturing method of the present invention will be additionally described with reference to FIG. 2 in which only the vapor deposition chamber is shown. Two evaporation tanks 5a and 5b are arranged in the vapor deposition chamber 4, and the Al-Ti alloy bath 6 is provided in the evaporation tank 5a on the upstream side with respect to the traveling direction of the metal material 1 to be plated.
a, and a pure Al bath 6b is prepared in the evaporation tank 5b on the downstream side. An electron beam 11 generated from an electron gun 10 provided on the side wall of the vapor deposition chamber 4 is deflected downward by a magnetic field formed in a space near the evaporation tank by a deflection coil (not shown), and the evaporation tank 5a The surfaces of the evaporation baths 6a and 6b prepared in 5b are irradiated while being operated in the plate width direction of the metal material 1 to be plated.

Al-Ti mixed vapor and pure Al vapor are generated from the bath surfaces of the evaporation baths 6a and 6b heated by the electron beam 11, respectively, and are vapor-deposited on the lower surface of the running metal material 1 to be plated. At this time, the Al-Ti mixed vapor is vapor-deposited first on the surface of the metal material to be plated to form an Al-Ti alloy plating layer. Subsequently, pure Al vapor is vapor-deposited thereon to form a pure Al plating layer. By such a manufacturing method, the vapor-deposited Al / Al-Ti alloy two-layer plating layer of the present invention can be applied on a desired metal substrate.

Al is a metal having a high vapor pressure, and it is possible to easily generate Al vapor by an electron beam heating method. Ti is a metal whose vapor pressure is lower than that of Al, but it is possible to obtain a sufficient vapor amount (vaporization rate) by an electron beam heating method having a high energy density. In the manufacturing method of the present invention, the lower layer Al-Ti
Al and T are used as evaporation raw materials for forming the plating layer.
Focusing on the formation of the alloy bath of i, the feature is that Al and Ti are simultaneously evaporated from the molten bath.

Al and Ti each independently form a molten bath in the evaporation tank when heated in a vacuum as described above, and a stable evaporation rate can be obtained from the surface of the molten bath. By alloying with Ti,
It was confirmed that an Al-Ti alloy molten bath was formed, and it was found that the mixed vapor of Al and Ti can be stably evaporated from the surface of the alloy bath.

Therefore, in order to obtain the Al / Al-Ti alloy vapor deposition two-layer plating of the present invention, the vapor Al bath evaporation tank 5b and the Al-Ti alloy bath evaporation tank 5a are placed in the running direction of the metal material 1 to be plated. Are placed in parallel with each other, and the Al
By generating the vapor and the Al-Ti mixed vapor, the vapor can be vapor-deposited on the surface of the traveling metal substrate to provide a desired two-layer plating film.

In order to obtain the lower plating layer defined in the present invention, it is necessary to control the composition of the Al-Ti mixed vapor and its evaporation amount (evaporation rate). In particular, the evaporation method from an Al-Ti alloy bath, which is one of the features of the production method of the present invention, can be achieved by appropriately adjusting the Al and Ti ratios in the alloy bath, that is, the composition of the alloy bath. Is. The composition of the alloy bath and the composition of the vapor mixture of Al and Ti vaporized from the surface of the alloy bath do not coincide with each other due to the difference in vapor pressure between the two, and compared with the Ti content in the bath, The Ti content is always small. However, for a given arbitrary alloy bath composition, the obtained mixed vapor composition is uniquely determined if the bath surface temperature is constant. Therefore, the Ti content in the lower plating layer specified in the present invention is The bath composition range of the alloy bath for obtaining can be uniquely determined. Further, if the mixed vapor composition and Al and Ti corresponding to the evaporation amount are continuously supplied to the alloy melting bath at the same time, the alloy bath composition can always be kept constant, and as a result, the evaporated vapor composition,
The amount of evaporation can also be maintained stably.

The essence of the manufacturing method of the present invention is as described above. In order to obtain the vapor-deposited Al / Al-Ti alloy two-layer plating, the evaporation bath surface shown in FIG. It is necessary to appropriately adjust the distance Hv and the distance D between both evaporation baths. When Hv is sufficiently large with respect to the length of D, the Al-Ti mixed vapor generated from the evaporation tank 5a and the pure Al vapor generated from the evaporation tank 5b reach the surface of the plated zone. An intermediate layer, which is a diffusion reaction layer of both layers, is formed. The intermediate layer is an Al-Ti alloy plating layer having a Ti content smaller than that of the lower Al-Ti alloy plating layer, and basically even if such an intermediate layer is formed, the performance of the obtained surface treatment material is improved. The surface, in particular, the corrosion resistance is not impaired at all, and basically the Al-Ti alloy plating layer can play the same role as the lower plating layer. Therefore, even when it has a plated layer structure in which the intermediate layer is present, it does not depart from the scope of the present invention, and is defined in the present invention as a highly corrosion-resistant surface-treated metal material.

However, when the product specifications are such that the amount of pure plating on the upper layer is small and the amount of Al-Ti alloy plating on the lower layer is large, the intermediate layer is generated to produce pure Al plating on the upper layer. The deposition amount of the layer decreases from the target value, and when the intermediate layer is included in the category of the Al-Ti alloy plating layer in combination with the lower plating layer, the deposition amount of the lower layer increases as a result. There is a possibility that the upper pure aluminum plating amount will fall below the lower limit of 1/5, which is the lower limit of the applied plating amount ratio R. Therefore, in the present invention, since the structure of the vapor deposition chamber is not specified, the values of Hv and D are not particularly limited, but of the vapor deposition chamber used for producing the vapor deposition plated surface-treated material of the present invention. It is preferable to appropriately select the manufacturing conditions for obtaining the desired plating adhesion amount ratio R depending on the structure and the evaporation layer arrangement method.

The heating evaporation source of the evaporation raw material in the present invention is not particularly limited as long as it is a high energy beam capable of evaporating pure Al and an Al-Ti alloy, and an electron beam or a laser beam is exemplified, among others. An electron beam is mentioned as a preferable example. That is, the electron beam is a high energy and high energy density heating source,
Although an electron gun for generating an electron beam is expensive, it has excellent maintainability and is advantageous in that the electron beam can be easily generated and stopped. Further, since the electron beam can directly irradiate the surface of the metal raw material to be vaporized, the heating / evaporating efficiency is high and the vaporization rate of the vaporizing raw material can be increased. In particular, since Ti, which is an essential component in the vapor-deposited plating layer of the present invention, has a vapor pressure smaller than that of Al, the electron beam heating method is suitable for obtaining a sufficient Ti evaporation rate from an industrial viewpoint. ing. Further, in the electron beam heating method, an electron beam generated from one electron gun is supplied to each evaporation raw material separately charged in a plurality of evaporation tanks at each evaporation tank at an extremely short cycle time. By scanning the surface of each evaporation bath while jumping in between, each evaporation source can be heated and evaporated all at once. Due to such characteristics, there is an advantage that various alloy platings composed of a plurality of elements and multilayer plating can be easily manufactured.

Further, in vacuum vapor deposition, it is also effective to employ a contract ion plating method in which each metal vapor generated from the evaporation layer is ionized by using a high frequency wave or the like and vaporized on the substrate. When this method is adopted, it is possible to obtain a film that is more precise and has no pinhole defect or the like and excellent adhesion.

[0044]

The present invention will be described in more detail with reference to the following examples, but the following examples are not intended to limit the present invention, and all modifications can be made without departing from the spirit of the preceding and the following. It is included in the technical scope of the present invention.

Example 1 Using the continuous vapor deposition plating equipment shown in FIGS. 1 and 2,
Vapor-deposited Al / Al-Ti alloy 2 under various conditions shown below
A layer-plated steel sheet was produced. <Deposition Plating Conditions> be plated range: cold-rolled steel (low carbon Al-killed steel) to be plated bands Pretreatment: alkaline electrolytic degreasing - washing - introduced into the gas reduction furnace by H ₂ -N ₂ gas mixture after drying, Pre-cleaning treatment by reduction of steel sheet surface-Temperature of plated material before plating: 200 to 350 ° C-Evaporation raw material: Al Al-Ti alloy-Evaporation tank: Evaporation tank for Al bath: High-purity fused alumina evaporation tank Al-Ti Evaporation tank for alloy bath: Graphite evaporation tank-Heating evaporation source of evaporation raw material: Al bath: Continuous supply by Al wire Al-Ti alloy bath: Continuous supply of Al wire and Ti wire into the alloy bath by independent wire supply devices- Heating evaporation source of evaporation material: Pierce type electron gun (maximum output 3
00kw) ・ Deposition degree of vacuum in the deposition chamber: 1 × 10 ^-2 Pa or less ・ Control method of coating amount and plating composition: Total output of electron beam and Al of total output
Control of distribution ratio to bath and Al-Ti alloy bath Control by combination of both running speed of plated zone

<Evaluation Test for Corrosion Resistance><EvaluationTest-1> Cross-cut scratches with a cutter knife and overhanging with Erichsen (overhanging height 7 mm) were applied to the surface of the plated layer, and the end face tape-sealed was used as a test material. A salt spray test (5% NaCl aqueous solution, 35 ° C.) was performed, and evaluation was made by the test time until red rust due to corrosion of each test material occurred. Corrosion Resistance Evaluation Criteria ⊚: Excellent corrosion resistance: more than 5000 hours of red rust occurrence Δ: Slightly inferior corrosion resistance: 100 to 5000 hours of red rust occurrence ×: Poor corrosion resistance: Less than 1000 hours of red rust occurrence

[0047]

[Table 1]

<Evaluation Test-2> Each of the test materials having the exposed cut surface was immersed in a saline solution and evaluated by the time until red rust was generated from the steel plate portion of the cut surface. Corrosion Resistance Evaluation Criteria ⊚: Excellent corrosion resistance: Red rust generation for more than 100 hours Δ: Corrosion resistance slightly poor: Red rust generation for 24 to 100 hours ×: Corrosion resistance poor: Red rust generation for less than 24 hours The obtained results are shown in Table 2 together with the comparative material.

[0049]

[Table 2]

As is clear from Tables 1 and 2, the vapor-deposited Al / Al-Ti alloy double-layer plated steel sheet specified in the present invention has excellent corrosion resistance. On the other hand, in the case of not having the two-layer plating structure of the present invention, or even in the two-layer plating structure, the Ti content in the lower plating layer is less than the value specified in the present invention, or the plating adhesion ratio is within the specified range. If it deviates, it can be seen that the corrosion resistance is insufficient.

Further, it can be seen that the hot-dip plated steel sheet used as a comparative material has insufficient corrosion resistance regardless of its type, and is inferior in corrosion resistance to the plated steel sheet of the present invention.

[0052]

EFFECTS OF THE INVENTION The present invention is constituted as described above, and has made it possible to provide a surface-treated metal material which is excellent in heat resistance, moldability, corrosion resistance, especially pore corrosion resistance. In addition, the surface-treated metal material as described above can be obtained efficiently at low cost by the manufacturing method of the present invention.

[Brief description of drawings]

FIG. 1 is a schematic view showing an example of a continuous vacuum vapor deposition apparatus used in the manufacturing method of the present invention.

FIG. 2 is a schematic view showing a vapor deposition chamber of an example of a continuous vacuum vapor deposition apparatus used in the manufacturing method of the present invention.

[Explanation of symbols]

 1 metal material to be plated 2a inlet side vacuum seal device 2b outlet side vacuum seal device 3 deflector roll 4, 4a, 4b vacuum deposition chamber 5a Al-Ti alloy evaporation tank 5b Al evaporation tank 6a Al-Ti alloy bath 6b Al bath 7 support Roll 8 Al wire 9 Ti wire 10 Electron gun 11 Electron beam

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tota Ayabe 1 Kanazawa Town, Kakogawa City, Hyogo Prefecture Kamido Steel Works, Ltd. Inside the Kakogawa Steel Works (72) Atsushi Kato 1 Kanazawa Town, Kakogawa City, Hyogo Prefecture Kamizawa Co., Ltd. Toko Works Kakogawa Works (72) Inventor Shoji Miyake 1 Kanazawa-cho, Kakogawa City, Hyogo Prefecture Kadodo Works Kakogawa Works

Claims (3)

[Claims] 1. An Al—Ti alloy vapor deposition plating layer containing 1 to 30% of Ti (meaning weight%; the same applies hereinafter) is formed on the surface of a metal substrate, and a pure Al vapor deposition plating layer is further formed thereon. Highly corrosion-resistant surface-treated metal material characterized by being processed. 2. The surface-treated metal material according to claim 1, wherein the highly-corrosion-resistant surface-treated metal material satisfies the following formula [1]. ⅕ ≦ R ≦ 1 ... [1] where R is the amount of the pure Al vapor deposition plated layer [Al]
(G / m ² ), [Al] / when the adhesion amount of the Al—Ti alloy vapor deposition plating layer is [Al—Ti] (g / m ² ).
Represents [Al-Ti]. 3. When continuously performing vapor deposition plating on a metal base material, an Al—Ti alloy evaporation tank is provided on the upstream side and an Al evaporation tank is provided on the downstream side in the vacuum evaporation chamber with respect to the running direction of the base metal. Al-Ti mixed vapor and Al vapor are generated by arranging them in parallel and heating each evaporation tank with a high-energy beam, and the metal substrate whose surface has been cleaned is continuously run through the vacuum deposition chamber. , Evaporated Al / A on metal surface
A method for producing a highly-corrosion-resistant surface-treated metal material, which comprises performing 1-Ti alloy-based two-layer plating.