WO2018159888A1 - Tin/magnesium thin film formed on zinc plated layer and manufacturing method therefor - Google Patents

Abstract

The present invention relates to a tin/magnesium thin film formed on a zinc plated layer and a method for manufacturing the same. The method comprises the steps of: preparing a substrate on which a zinc plated layer is formed; physically depositing magnesium (Mg) and tin (Sn) on the surface of the zinc plated layer to form a magnesium thin film and a tin thin film; and diffusing zinc, magnesium, and tin atoms through heat treatment to form a thin film in which tin/magnesium mutual solubility and intermetallic compounds are present. Due to these features, it is possible to provide a shielding effect and sacrificial anode property by the diffusion between components and the formation of intermetallic compounds through a physical vapor deposition method and the heat treatment. Furthermore, it is possible to obtain the effect that a tin/magnesium thin film can be produced on a zinc-plated substrate stably, densely-stably and rapidly by comprehensively considering and controlling the influence of crystal orientation according to production conditions.

Description

Tin / magnesium thin film formed on the galvanized layer and its manufacturing method

The present invention relates to a tin / magnesium thin film formed on a galvanized layer and a method for manufacturing the same, and in particular, a strong barrier due to diffusion movement between components through the physical vapor deposition and heat treatment, and the formation of intermetallic compounds. It not only provides corrosion resistance with sacrificial anode effect, but also comprehensively controls the influence of crystal orientation according to the fabrication conditions so that corrosion products on the surface layer can be rapidly and densely and stably formed on the galvanized substrate. It relates to a tin / magnesium thin film formed and a method of manufacturing the same.

The metal material is an inorganic material composed of one or more metal elements, and includes iron (Fe), copper (Cu), aluminum (Al), magnesium (Mg), zinc (Zn), tin (Sn), and the like. And some nonmetallic elements such as (C), nitrogen (N) and oxygen (O). In addition, the metal material has a crystal structure, the elements are arranged regularly, relatively strong and ductile at room temperature, and also has electrical properties. In particular, steel materials applied to fasteners, screws, nails, metal sheets, automobile parts, etc., among other metal materials, can withstand corrosion while also resisting corrosive media such as chlorine, neutral media, biodiesel, alcohol, fuel, or cooling fluids. As a material for improving the capability, it can be used to plate the surface of the metal substrate.

Among the plating methods used to solve the corrosion problem of steel materials, surface treatment by zinc (Zn) plating is widely used. Zinc is reacted with water or oxygen in the atmosphere to form zinc oxide (ZnO) and zinc hydroxide. (Zn (OH) ₂₎ and Simon, Bakelite _{(Zn 5 (OH) 8 Cl} 2 · H 2 O, simonkolleite) and to form a stable and dense corrosion products, such as, by the shielding role against external corrosive environment through which the steel It serves to protect the material. However, as industrialization becomes more advanced and the field of application is diversified, a variety of measures must be considered to ensure better corrosion resistance as the material is exposed to more severe corrosive environments. In order to improve the corrosion resistance of the plating, it is easiest to increase the coating amount, but this technique is not suitable in terms of resources, energy saving, weldability, weight reduction, etc., which are considered in commercialization. Therefore, the research of the material development through alloying to extend the life of the coating layer without reducing the sacrificial corrosion resistance while reducing the plating amount of zinc has been made.

Metal plating products are mainly produced by wet processes such as electroplating or hot dip plating. Electroplating is widely used because of its uniform and beautiful surface and good processability, but it has problems such as an increase in power consumption, an increase in manufacturing cost, and limitation of elemental addition, which are accompanied by an increase in plating precipitation. In addition, in the case of hot-dip galvanizing, there is an advantage in that it is plated thickly at low cost, but due to the characteristics of the process, it is plated on both sides, resulting in waste of resources. layer) It is difficult to produce. Since the wet process has reached the technical level of almost saturation level due to the technology development of the last decades, it is very difficult to meet the requirements of future industrial sites, and the waste water and harmful chemicals generated during the wet process and Environmental pollution, low energy efficiency, waste of resources, plating failure rate and economic feasibility due to thin film trend are difficult to secure, and development of high corrosion resistant thin film material is urgently needed through process improvement.

Therefore, recent research institutes and academia in the United States, Europe, and Japan are making efforts to replace existing wet processes applied to steel products, and new materials and eco-friendly high-speed processes are being researched and developed. Among them, physical vapor deposition (PVD), which enables the production of high-performance thin films by controlling atomic particles in a vacuum, has attracted attention. Compared to the wet process, physical vapor deposition has advantages such as less porosity, coating various material systems, easier deposition rate control, and high quality films of high density for various types of alloys and multilayer plating.

Therefore, the present invention provides a shielding effect and sacrificial anode characteristics due to diffusion movement between components through the physical vapor deposition method and heat treatment, and the formation of intermetallic compounds, as well as the effects of crystal orientation depending on the manufacturing conditions. The present invention provides a tin / magnesium thin film prepared on a galvanized substrate so that corrosion products of the surface layer can be densely and stably formed quickly by controlling the same, and a method of manufacturing the same.

The above object is to prepare a substrate on which a galvanized layer is formed; Physically depositing magnesium (Mg) and tin (Sn) on the surface of the galvanized layer to form a magnesium thin film and a tin thin film; Achieved by the method of manufacturing a tin / magnesium thin film formed on a galvanized layer comprising the step of diffusing the zinc, magnesium and tin atoms through heat treatment to form a thin film containing tin / magnesium inter-employment and intermetallic compounds do.

Here, the zinc plating layer is preferably formed by electroplating, hot-dipping or physical vapor deposition (PVD) method, the step of forming the magnesium thin film and tin thin film, the zinc Physically depositing magnesium on the surface of the plating layer to form the magnesium thin film, and then physically depositing tin on the surface of the magnesium thin film to sequentially laminate the tin thin film.

In addition, the magnesium thin film and the tin thin film is formed to have a thickness ratio of 0.5 to 2 times each other, the physical vapor deposition, vacuum evaporation (vacuum evaporation), sputtering (sputtering), ion plating (ion plating) and It is preferable to use a method selected from the group consisting of mixtures thereof, and the heat treatment is preferably performed at 232 ° C. or lower, which is the melting point of tin.

The above object is also formed on the surface of the galvanized layer, the tin / magnesium thin film formed on the galvanized layer, characterized in that the zinc, magnesium and tin atoms are heat-transferring thin film formed by a solid solution or an intermetallic compound through heat treatment. It is also achieved by

According to the configuration of the present invention described above, through the physical vapor deposition and heat treatment, the diffusion effect between the components, the intermetallic compound (intermetallic compounds) due to the formation of shielding effect and sacrificial anode characteristics, as well as the effect of crystal orientation according to the manufacturing conditions By considering and controlling the overall composition, it is possible to obtain the effect that the tin / magnesium thin film is manufactured on the galvanized substrate so that it can be stably and tightly and stably produced quickly.

1 and 2 is a flow chart of a method for manufacturing a tin / magnesium thin film formed on the galvanized layer,

3 is a graph showing the deposition rate of magnesium and tin,

Figure 4 shows the surface of the Sn / Mg thin film, cross-sectional morphology observation results and the schematic diagram of the coating layer conditions through the GDS analysis,

5 is a thin film surface, cross-sectional morphology of the Sn / Mg test specimen and the comparative material after the heat treatment after fabrication,

FIG. 6 shows the composition distribution of the Sn / Mg thin film measured in the depth direction from the surface with brown lines (Sn), green lines (Mg), red lines (O), pink lines (Zn), and blue lines (Fe). It's a graph,

7 is an image showing the EPMA analysis result of the Sn / Mg thin film,

8 is a graph showing the appearance observation result of the salt spray test piece.

Hereinafter, a tin / magnesium thin film formed on a zinc plated layer according to an embodiment of the present invention and a manufacturing method thereof will be described with reference to the accompanying drawings.

The present invention includes a galvanized layer and a tin / magnesium thin film formed on the surface of the galvanized layer, and the zinc, magnesium and tin atoms present in the galvanized layer and the tin / magnesium thin film through heat treatment are diffused and moved to form a solid solution or an intermetallic compound. It is characterized by the thin film formed.

As a method of manufacturing such a tin / magnesium thin film, as shown in FIGS. 1 and 2, first, a substrate on which a galvanized layer is formed is prepared (S1).

Preparing a substrate to increase the corrosion resistance is prepared by forming a galvanized layer thereon. The galvanized layer may be formed through various methods such as electroplating for applying a voltage to a zinc plating solution, applying a voltage, hot-dipping for processing a substrate in a molten zinc bath, and physical vapor deposition (PVD). Can be formed. In addition, the substrate is not particularly limited in material, such as iron (Fe), steel (stainless steel), it is easy to apply a substrate having any material.

Physically depositing magnesium and tin on the surface of the zinc plating layer to sequentially form a magnesium thin film and a tin thin film (S2).

Physically depositing magnesium on the surface of the zinc plating layer to form a magnesium thin film, and then physically depositing tin on the surface of the magnesium thin film to sequentially stack the tin thin film to form a tin / magnesium (Sn / Mg) thin film. Tin (Sn) prevents corrosion from external water or oxygen, and magnesium (Mg) is a metal that is more corrosive than tin, so physically deposit magnesium and then physically deposit tin on the surface. To ensure that the tin film is placed on the most surface to help prevent corrosion. The magnesium thin film and the tin thin film thus formed are preferably formed to have a thickness ratio of 0.5 to 2 times each other. If it is out of this range, in the process of alloying through heat treatment later, the ratio of the composition is biased to one side, so that the desired amount of alloy cannot be obtained.

Physical vapor deposition (PVD) is a dry process using plasma under a vacuum atmosphere, and has various advantages over wet processes using a conventional liquid. First, since it is a dry process using gas, no waste liquid treatment is required, and pollution measures such as exhaust gas treatment are easy. Secondly, it is not necessary to heat the reaction vessel to a high temperature like a wet process using a liquid, and a high reaction rate can be obtained at a low temperature because high energy electrons in the plasma decompose gas to make a large amount of active species. Third, even if the thickness of the coating film within a few μm, various kinds of thin films such as metals, alloys, compounds, ceramics and organic polymers can be easily manufactured in the film composition. Such physical vapor deposition is preferably used by a method selected from the group consisting of vacuum evaporation, sputtering, ion plating, and mixtures thereof. In particular, since magnesium is almost impossible to coat using a wet process, it is preferable to form a magnesium thin film on the surface of the zinc plating layer through physical vapor deposition of magnesium.

Through the heat treatment to form a tin / magnesium thin film (S3).

The heat treatment in this step is to apply heat to heat a specific atom so as to permeate between other atoms to form an alloy. In the present invention, invasive solid solution, substituted solid solution, or intermetallic compound formation is any shape. It may consist of. That is, through heat treatment, zinc and magnesium are diffused and moved toward tin, and tin is diffused and moved toward zinc and magnesium to form a tin / magnesium thin film on the surface of the zinc plated layer. The thus formed tin / magnesium thin film includes some zinc, magnesium, and tin, respectively, and some of the tin / magnesium has a zinc / magnesium and tin / magnesium alloy. As such, since zinc, magnesium, tin, zinc / magnesium, and tin / magnesium are present by the heat treatment, an alloy thin film having a delayed corrosion rate and improved corrosion resistance can be obtained. In particular, zinc / magnesium alloy and tin / magnesium alloy generally corrode magnesium rapidly during the corrosion process, and zinc and tin, which bind magnesium, do not separate in the state of being bonded with magnesium atoms, thereby delaying corrosion. In other words, the combination increases the corrosion resistance of the tin / magnesium thin film.

As the time and temperature increase during the heat treatment, the surface particle size of the alloy thin film increases, and zinc / magnesium and tin / magnesium are bonded to each other. At this time, the heat treatment temperature is preferably made of 232 ℃ or less melting point of the tin, when the heat treatment at a temperature exceeding 232 ℃ the surface gloss of the tin / magnesium thin film is changed to light brown to cause partial peeling. This is undesirable because it may adversely affect the corrosion resistance due to deformation of the surface morphology and reduced adhesion. In addition, there is a problem in that the diffusion reaction is difficult due to the deformation and oxidation of the morphology, so that zinc / magnesium and tin / magnesium alloys cannot be obtained properly.

Hereinafter, a tin / magnesium thin film manufacturing method formed on the zinc plated layer of the present invention will be described in more detail with reference to Examples.

<Example>

Tin / magnesium (Sn / Mg) thin film was fabricated on the surface of hot dip galvanized (GI60- 8.4㎛) by using DC-magnetron sputtering method which is one of physical vapor deposition methods And the corrosion resistance of the heat treatment was compared and analyzed, to determine the effectiveness of the Sn / Mg coating film of high corrosion resistance and to optimize the manufacturing conditions. Sputtering is a kind of vacuum deposition method. When the accelerated electrons collide with the gas atom at a relatively low degree of vacuum and collide with the negative electrode target to be coated, the atom that receives energy greater than the bonding force of the atoms is transferred to the outside. The principle is that the atoms bounce off and fly through the mean free path to the substrate opposite the cathode. In general, in the coating process, an inert gas is used to form a plasma to control chemical reactions and component changes. Here, argon (Ar) gas having 15.8 eV ionization energy is used.

In the present embodiment, the target metal used for the production of Sn / Mg thin film was used as purity 99.99% magnesium (Mg) and 99.99% tin (Sn), and a hot dip galvanized steel sheet (GI 60-8.4) as the deposition substrate. Μm) was used. In addition, in order to compare the corrosion resistance of the prepared coating layer, a pure zinc and pure tin coated hot dip galvanized steel sheet GI60 (8.4㎛), coated GI60 (8.4㎛), coated GI 144 (20㎛) was prepared. Hot dip galvanizing (GI60-8.4㎛) used as a substrate in the fabrication of specimens has a coating weight of 120g / double-sided zinc (Zn) and sputtering coating using a vacuum process on one side, 60g / M 2 becomes the coating layer constituent. As a pretreatment process for the coating of hot-dip galvanized (GI60- 8.4㎛) steel sheets, the surface-treated rust preventive oil was degreased, ultrasonically cleaned in acetone and ethanol solvents for 15 minutes using an ultrasonic cleaner, and then dehumidified with a dryer, and then fixed to a test specimen supporter. .

In the preparatory step of forming a coating film on a hot dip galvanized (GI 60-8.4㎛) steel sheet, the substrate was fixed to a test piece support, and the chamber was sealed to form a vacuum. First, a low vacuum rotary pump was used to exhaust the air at atmospheric pressure, and a high vacuum was produced using an oil diffusion pump preheated for about 1 hour. Subsequently, ion bombardment cleaning was performed at 350 V under vacuum for 30 minutes by introducing 100 sccm of Ar gas to remove an oxide film on the surface and to improve adhesion of the deposited film.

After the cleaning process of the test piece was finished, cleaning was performed by applying a voltage to the target mounted on the sputtering gun. The degree of vacuum and applied voltage during the target cleaning process were adjusted through preliminary experiments to favor the formation of magnesium (Mg), tin (Sn) sputtering rate and granular crystal morphology for argon gas. In addition, the composition and the deposition rate of the metal coating particles ejected on the target surface was stabilized to be kept constant. 3 is a graph showing deposition rates of magnesium and tin.

When the coating preparation was completed, a relatively low bias voltage was applied to the test specimen support, rotated by 90 °, and magnesium and tin targets were coated in order to prepare a double layer thin film. The bias voltage is generally applied because active metal ions ejected by continuous cleaning and sputtering of the substrate form a dense film and improve adhesion, but in this embodiment, only a minimum bias voltage is applied in consideration of the destruction of the bilayer structure. It was.

Heat treatment was performed in about 15 minutes in an atmosphere of 232 DEG C or lower, which is the melting point of tin. This is because the corrosion resistance is expected to be improved by the formation of dense and thick oxide film and intermetallic compound when exposed to corrosive environment. In the preliminary experiment, it was found that the solid solution and intermetallic compound formation through diffusion movement between components were disadvantageous as the melting point of tin (Sn) was higher than 232 ° C or longer. In other words, when the heat treatment is excessively necessary, the gloss of the surface of the coating layer is changed to light brown and partial peeling occurs. This is considered to adversely affect the corrosion resistance due to the decrease in the deformation adhesion of the surface morphology. Was set.

Based on the hot-dip galvanized (GI60-8.4㎛) steel sheet used as the substrate, the Sn / Mg coating layer was prepared in different ratios, and then heat-treated, and non-heat-treated Mg and Sn test specimens were prepared. In addition, a non-coated hot dip galvanized (GI60-8.4㎛) steel sheet and hot dip galvanized (GI144-20㎛) steel sheet was prepared together to evaluate the material properties and corrosion resistance. That is, the conventional non-coated hot dip galvanized (GI60-8.4㎛) steel sheet and hot dip galvanized (GI144-20㎛) with a zinc thickness of more than 2 times by sputtering, and then compared with the heat treated Sn / Mg coated specimens and evaluated the corrosion resistance. The correlation between material properties and corrosion resistance was elucidated.

Figure 4 shows the surface of the prepared Sn / Mg film, cross-sectional morphology observation results and the coating layer conditions by GDS analysis, the Sn thickness ratio of SMZ-A is larger than Mg, SMZ-B, SMZ-C are the same It can be seen that the Mg thickness ratio is made larger than Sn. First, the surface morphology observation results show that the grains of granular structure of Sn particles are densely covering the film, and the smaller the proportion of Sn, the smaller the size of the particles. In the case of the cross section, the thickness of the coating layer can be clearly distinguished according to the fabrication conditions. As the ratio of Sn decreases, the morphology of the upper coating layer changes from the columnar structure to the shape of the granular crystal. It is believed that when Sn film grows, the vicinity adjacent to Mg is formed in the form of particles along the coating surface, but grows in the form of columnar tablet from a certain thickness or more. On the other hand, the Mg layer grew long in the form of columnar tablets. It is believed that the surface and cross-sectional morphologies of the Sn / Mg films fabricated with this tendency will affect the corrosion resistance.

5 shows the thin film surface and cross-sectional morphology of the Sn / Mg test specimen and the comparative material after heat treatment after fabrication. Compared with the non-heat treated test pieces, the heat treated test pieces were found to have a larger surface particle size and bonded to each other as heat treatment time and temperature increased. In the case of cross-section specimens, atypical morphology was observed at Sn / Mg interlayer boundaries with increasing heat treatment conditions, presumably because of diffusion movement. In terms of fabrication conditions, the roughness of the surface coating layer according to the heat treatment was the best in SMZ-B, and the SMZ-A heat treated at 220 ° C. for 30 minutes showed the most uneven morphology. This morphology change is thought to be caused by the reaction with oxygen, the growth of the nucleus and the diffusion and alloying of the components between the coating layers during the heat treatment process.

On the other hand, when the MZ (Mg only), SZ (Sn only), GI60 (Zn 8.4㎛) and GI144 (Zn 20㎛) non-heat treated as a comparative test piece, MZ is a hexagonal particle having a grain size of about 200nm grain size They showed overlapped shapes, and SZ showed a granular morphology similar to SMZ-A.

In order to confirm the composition distribution according to the fabrication conditions of Sn / Mg (SMZ) film, energy-dispersive x-ray spectroscopy (EDS) point analysis and glow discharge atomic emission spectrometer (GDS) analysis were performed from the surface to the depth direction, and EPMA (electrone) was analyzed. The purpose of this study was to verify the results of the diffusion between layers of impact fractured sections in liquid nitrogen using prove x-ray microanalyzer analysis.

FIG. 6 shows the compositional distribution of the Sn / Mg film measured in the depth direction from the surface with brown lines (Sn), green lines (Mg), red lines (O), pink lines (Zn), and blue lines (Fe). . In the specimens with weak heat treatment conditions, Sn and Mg were clearly distinguished, and as the conditions were increased, Sn was diffused to the bottom of the coating layer and Mg was diffused to the surface. As a result, as the heat treatment increases, it can be seen that cross-diffusion and movement between the coating layer components occur. Summarizing the above GDS results, it was confirmed that as the heat treatment conditions increased, Sn tended to diffuse from the top to the bottom, and Mg and Zn moved from the bottom to the top. In particular, the best component diffusion such as Mg rises to the surface and descends throughout the Sn and Mg layers under the conditions of heat treatment of SMZ-B.

As a final step of the composition distribution analysis according to the fabrication conditions and heat treatment of the Sn / Mg film, the behavior of the components diffused from the surface to the substrate was analyzed using the EPMA mapping analysis of the cross section. Figure 7 shows the results of the EPMA analysis of the test piece, it can be seen that in the non-heat treatment step Sn and Mg are mainly distributed in each of the red color. In the case of mild temperature conditions (below 200 ℃, less than 15 minutes) as the heat treatment progressed, it was seen that the Sn component diffused and moved to the Mg thin film to form a Sn-Mg mixed section. Diffusion movement to the bottom, Sn-Mg and a small amount of Mg-Zn mixed section was confirmed. In addition, it was confirmed that the Sn layer partially agglomerated on the surface by reaction with Mg and oxygen when the heat treatment (above 200 ° C, more than 15 minutes) near the melting point of Sn, and the Zn component was diffused to the surface.

In order to compare and evaluate the corrosion resistance of Sn / Mg film according to fabrication conditions, the general surface and the X-cut specimens were exposed in the salt spray environment proposed in KS D 9502. In the corrosion trend, the specimen coated with Sn / Mg thin film showed up to 10 times better corrosion resistance than the substrate GI60 (8.4㎛). In addition, the difference in corrosion resistance was clearly confirmed according to the Sn / Mg ratio and the heat treatment conditions. When the heat treatment was performed under the SMZ-B condition, the corrosion resistance was the highest. It acts like a barrier to block the access of corrosion factors such as oxygen (O ₂ ) and water (H ₂ O) from the outside environment, and to accelerate the dissimilar metal corrosion reaction between the intermediate and lower coating layers as the corrosion accelerates. It is considered that the intermetallics, which can be inhibited by, have been formed properly. On the other hand, when the heat treatment at a weak temperature condition showed a tendency to decrease compared to the non-heat-treated specimens, as shown in the morphology observation of Figure 5, the surface particle size is temporarily increased, the dense oxide film formation is disadvantageous, Zn-related intermetallic compounds formed It is thought that it is not. In addition, in the case of strong heat treatment near the Sn melting point, the roughness of the surface morphology was increased and the diffusion of Mg and Zn components was difficult as in the material properties identified above. In other words, the formation of intermetallic compound by morphology uniformity and component diffusion is the main factor for showing the excellent corrosion resistance, and it is considered that the above conditions are satisfied when heat treatment is carried out at less than 200 ℃ under SMZ-B conditions.

Compared with GI144 (20㎛), it showed up to 4 times better corrosion resistance, which means that the sputtering and heat treatment of GI60 substrate (Zn-8.4㎛) reduces zinc plating amount to 2 times or less and up to 4 times better corrosion resistance. Subsequently, the MZ (Mg only) test specimens showed better corrosion resistance than the SZ (Sn only) coated test specimens, and the corrosion resistance was lower than that of the Sn / Mg coated test specimens. This is thought to have an effect of improving the corrosion resistance by inserting the upper Sn thin film and the Mg thin film at the same time to have a dense oxide film on the surface and sacrificial corrosion protection.

On the other hand, in order to check the sacrificial method and the barrier effect (barrier) intensively, X-cuts on the surface and the appearance of the specimens exposed to the salt spray environment is shown. As mentioned above, in order to improve the corrosion resistance of the coating film, it is advantageous to form an oxide film having a dense surface, and have a sacrificial anticorrosive property to supply electrons by ionizing the coating film before the steel sheet is exposed and red rust occurs. In particular, the Sn / Mg film fabricated in this study not only uses three different metals but also Mg and Zn tend to have higher ionization tendencies than iron, and show relatively dislocation values. This is because exposure with iron can accelerate corrosion.

As the corrosion progressed, it was confirmed that the Zn corrosion product covered the white surface from the beginning, and the overall red rust generation time was longer than that of the general surface specimens. In other words, as the heat treatment conditions increased, the red-blue occurrence time of X-cut specimens was slower than the non-heat treatment and low-temperature heat treatment specimens. It is presumed to have sacrificial effects by minimizing) and by supplying electrons continuously. SMZ-B coatings in particular were found to be the most favorable conditions. 8 is a graph showing the appearance observation results of the salt spray test specimens, and as confirmed above, the SMZ-coated specimens showed superior corrosion resistance compared to the comparative specimens.

As a result of analyzing the material properties of the Sn / Mg film according to the fabrication conditions, the morphology of the film produced by varying the ratio of Sn and Mg was in the form of granular crystals, and a uniform single layer was formed through SEM and GDS analysis. I could confirm that. At this time, the surface morphology was gradually grown as the heat treatment was combined in a mass (mass), it was confirmed that the surface roughness increased during the heat treatment under the harshest heat treatment conditions. It is thought that the morphology is the best when heat treated at 200 ° C. or lower and exhibited excellent corrosion resistance as well as dense oxide film formation from corrosive environments.

Non-thermally treated specimens showed about 70 ~ 80 wt% Sn, about 10 wt% Mg, about 5 wt% Zn content through the surface composition distribution of the fabricated thin film. There was a tendency to diffuse migration and a mixed region of Sn-Mg and Mg-Zn was observed. The composition distribution of the coating layer was most uniform when the SMZ-B specimens were heat-treated at 200 ° C or lower, and the SMZ-A and SMZ-C exhibited defects in the coating layer and the SMZ-C showing a narrow mixed region between components as the corrosion progressed. In comparison, the Sn layer on the upper side is the barrier (barrier) to block the external corrosion factor, it is confirmed that the role of the cathode coating and the anode coating for supplying electrons while dissolving a relatively easy to ionized metal component at the same time.

The present invention relates to a tin / magnesium thin film formed on a galvanized layer and a method for manufacturing the same, and in particular, a strong barrier due to diffusion movement between components through the physical vapor deposition and heat treatment, and the formation of intermetallic compounds. It not only provides corrosion resistance with sacrificial anode effect, but also comprehensively controls the influence of crystal orientation according to the fabrication conditions so that corrosion products on the surface layer can be rapidly and densely and stably formed on the galvanized substrate. Tin / magnesium thin film to be formed and its manufacturing method are available.

Claims (7)

1. In the method of manufacturing a tin / magnesium thin film formed on the galvanized layer,

   Preparing a substrate on which a galvanized layer is formed;

   Physically depositing magnesium (Mg) and tin (Sn) on the surface of the galvanized layer to form a magnesium thin film and a tin thin film;

   A method of manufacturing a tin / magnesium thin film formed on a zinc plated layer comprising the step of diffusing a zinc, magnesium and tin atoms through heat treatment to form a thin film in which tin / magnesium mutual employment and an intermetallic compound are present.
2. The method of claim 1,

   The galvanized layer is a tin / magnesium thin film manufacturing method formed on the galvanized layer, characterized in that formed by electroplating, electroplating (hot-dipping) or physical vapor deposition (PVD) method.
3. The method of claim 1,

   Forming the magnesium thin film and tin thin film,

   Tin formed on the galvanized layer, characterized in that the magnesium thin film is first formed on the surface of the zinc plated layer to form the magnesium thin film, and then the tin thin film is sequentially laminated by physically depositing tin on the surface of the magnesium thin film. Magnesium thin film manufacturing method.
4. The method of claim 1,

   The thickness of the magnesium thin film and the tin thin film is a tin / magnesium thin film manufacturing method formed on the galvanized layer, characterized in that to form a thickness ratio of 0.5 to 2 times each other.
5. The method of claim 1,

   The physical vapor deposition is a tin / magnesium thin film formed on the galvanized layer characterized in that using a method selected from the group consisting of vacuum evaporation, sputtering, ion plating, and mixtures thereof. Way.
6. The method of claim 1,

   The heat treatment is a tin / magnesium thin film manufacturing method formed on the galvanized layer, characterized in that made at 232 ℃ or less.
7. In the tin / magnesium thin film formed on the galvanized layer,

   Tin / magnesium thin film formed on the surface of the galvanized layer, zinc, magnesium and tin atoms through the heat treatment is a thin film formed in the galvanized layer characterized in that the tin / magnesium mutual employment and the intermetallic compound is present in the diffusion.

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