JPH05222513A - Manufacture of vapor deposition plated corrosion resistant steel - Google Patents

Abstract

PURPOSE:To manufacture a vapor deposition plated corrosion resistant steel excellent in the adhesion of a vapor-deposited film and corrosion resistance by subjecting an austenitic stainless steel having a specified componental compsn. to specified ion bombardment treatment and vapor deposition plating and thereafter executing heat treatment. CONSTITUTION:An austenitic stainless steel contg., by weight, 0.01 to 0.06% C, 0.1 to 5.0% Si, 8.0 to 35.0% Cr, 7.0 to 50.0% Ni, <=0.3% N, 0.001 to 2.O% Ti and/or 0.001 to 2.0% Nb is used as a substrate. This substrate is subjected to preheating to 150 to 500 deg.C in a vacuum tank of a nonoxidizing atmospheric gas of 2X10<-4> to 8X10<-6>Torr H2O partial pressure and is subjected to bombardment treatment under -20 to -400V bias voltage. In this way, an oxide film essentially consisting of Cr oxide is formed on the surface of the substrate. Next, this substrate is applied with vapor deposition plating of metal or ceramics and is thereafter held to the temp. range of 500 to 1150 deg.C for >=0.5min in a nonoxidizing atmosphere held at -15 to -55 deg.C dew point.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a vapor-deposited corrosion-resistant steel material, which has excellent adhesion to a vapor-deposited film and excellent corrosion resistance.

[0002]

2. Description of the Related Art Stainless steel materials are widely used for various purposes such as building materials for construction because of their excellent corrosion resistance and beautiful surface color tone. Further, in recent years, with the diversification of tastes and the sophistication, high-grade stainless steel sheets have begun to be used even in the fields where plated steel sheets have been conventionally used. Hereinafter, a steel plate will be described as an example of the steel material. Since a stainless steel sheet can be beautifully colored with a beautiful design by an anodic oxidation method or the like, it is often used while keeping the metallic luster due to the surface coloring.
Therefore, it is necessary that the original corrosion resistance is not impaired even by surface coloring.

By the way, in recent years, some substances are vapor-deposited on the surface of stainless steel materials by vapor deposition methods such as PVD method and CVD method to further improve the corrosion resistance while maintaining a metallic color tone, or to add a function other than the corrosion resistance. Then, it has begun to aim for higher functionality. For example, attempts have been made in various places to deposit a metal such as Ti or a ceramic film such as TiN on the surface of a stainless steel plate by an ion plating method. In the case of such a vapor deposition method, unlike the case of the above-mentioned anodizing method, since the vapor deposition film is coated on the metal surface, the corrosion resistance of the film as well as the adhesion of the film become a problem. That is, when a metal or ceramic film is vapor-deposited on a stainless steel plate by the vapor deposition method, the adhesion of the vapor-deposited film deteriorates due to the passive film present on the stainless steel plate, or the vapor-deposited plated material itself is stable and good. There was a problem that sufficient corrosion resistance was not ensured.

Therefore, in general, as a pretreatment for vapor deposition, etching treatment by plasma or ion beam is performed for the purpose of removing the passive film on the surface of the stainless steel plate. However, these pretreatments in the related art have been performed for the purpose of completely and desirably removing the passive film itself present on the surface of the stainless steel plate. However, in the vacuum chamber where the etching process is generally performed, fine dust particles of the deposition material deposited before that,
Alternatively, the suspended matter derived from the attached substances brought in with the substrate floats as fine dust, and it is intended to clean the surface by removing the passive film existing on the stainless steel plate surface. The etching process that satisfies the purpose of is not easy, but rather results in the adhesion of floating substances, which promotes the surface roughness of the deposition substrate,
It was also a cause of the generation of many pinhole defects entangled with the growth direction of the deposited material.

When a large number of such pinhole defects occur, stainless steel as a bare metal is often exposed at the pinhole portion of the vapor-deposited film, and even if a substance having excellent corrosion resistance is vapor-deposited, the corrosion resistance is poor. Since the surface of the vapor-deposited substrate is exposed through the pinhole, the steel plate itself, which is the substrate, is corroded, and the corrosion resistance of the vapor-deposited steel plate itself is not improved. Moreover, as is well known, when the corrosion resistance of the vapor deposition material and the vapor deposition substrate differ greatly, dissimilar metal contact corrosion (galvanic corrosion) occurs, and even if a metal or ceramics with excellent corrosion resistance is vapor deposited, the vapor deposition substrate itself The phenomenon that the corrosion resistance was inferior to that of the above was observed.

[0006]

An object of the present invention is to provide a corrosion-resistant protective coating on the surface of a stainless steel material in order to increase the added value of the stainless steel material. It is intended to solve the problems of not being sufficiently exhibited and the problems of such poor adhesion of the vapor deposition film to the substrate. That is, an object of the present invention is to use an austenitic stainless steel material as a vapor deposition substrate and further improve the adhesion of the vapor deposition material to the substrate when vapor-depositing a metal or ceramics on this to further improve the performance. In addition to reducing the pinhole defects themselves, even if pinhole defects are generated, it is possible to improve the corrosion resistance of the deposition substrate itself by etching treatment before deposition and heat treatment after deposition plating. Another object of the present invention is to provide a method for producing a vapor-deposited corrosion-resistant steel material, which is intended to reduce the degree of corrosion resistance deterioration of a vapor-deposited material caused by a pinhole.

[0007]

As already known, in order to improve the added value, metal and ceramics are vapor-deposited on a corrosion-resistant steel plate to improve the corrosion resistance of the vapor-deposited material to the vapor-deposited substrate. It is most preferable to reduce vapor deposition defects such as holes. However, it is extremely difficult to completely eliminate the pinholes in the formed vapor deposition film by various vapor deposition methods such as the current vacuum vapor deposition method or ion plating method.

On the other hand, the conventional pretreatment method for removing the surface passivation film rather promotes the generation of pinhole defects on the newly formed surface after the etching treatment, and promotes the corrosion starting from them. There was a problem of being done. Here, the present inventors have examined the pretreatment method under various conditions while also taking into consideration the results of the predecessor, but the atmosphere at the time of the ion bombardment treatment for the purpose of etching and its etching treatment By optimizing the substrate conditions, the oxide film formed on the surface of the austenitic stainless steel sheet after ion bombardment becomes an oxide film mainly composed of Cr, and by such means, the corrosion resistance of the vapor-deposited substrate surface is improved. It has been found that, even if the substrate is exposed due to a pinhole defect, the deterioration of the corrosion resistance of the vapor deposition material can be minimized.

Furthermore, the vapor-deposited plated material after vapor deposition is
When a specific heat treatment is performed in a furnace in which the dew point temperature in the furnace is controlled to create an atmosphere in which oxides mainly composed of Cr and Si with excellent corrosion resistance are formed, the adhesion of the deposited film is significantly improved and It was found that the corrosion resistance is further improved. That is, the target of the treatment of the present invention is, by weight, C: 0.01 to 0.06%, Si: 0.1 to 5.0%, Cr: 8.0 to 3%.
It is an austenitic stainless steel material containing 5.0%, Ni: 7.0 to 50.0%, N: 0.3% or less, and 0.001 to 2.0% in total of at least one of Ti and Nb.

According to the present invention, vapor deposition plating is performed using this as a substrate. The pretreatment method performed prior to vapor deposition plating is that the H ₂ O partial pressure is 2 × 10 ⁻⁴ to 8 × 10 ⁻⁶ Torr. The substrate is heated to 150 ° C in a vacuum chamber containing a non-oxidizing atmosphere gas.
The ion bombardment treatment is performed by applying a bias voltage of -20 to -400 V in the state of preheating above 500 ° C. By this pretreatment, an oxide film mainly composed of Cr oxide is formed on the substrate surface, and then vapor deposition plating is performed by a conventional method. After further vapor deposition plating,
In a furnace with a non-oxidizing atmosphere maintained at a dew point of -15 to -55 ° C, the temperature is maintained in the temperature range of 500 to 1150 ° C for 0.5 min or longer. Thus, according to the present invention, it is possible to manufacture a vapor-deposition corrosion-resistant steel sheet in which the generation of pinholes itself is reduced and the degree of corrosion resistance deterioration of the vapor deposition material due to the pinholes is reduced.

[0011]

As described above, in the method according to the present invention, in contrast to the conventional etching process for removing the surface passivation film, in contrast to the etching by the ion bombardment process, the main surface of the substrate is mainly composed of Cr. To promote oxidation such that an oxide is formed, to form a highly dense Cr oxide-based oxide layer that is highly desirable in terms of corrosion resistance,
In other words, the feature is that the removal of the passivation film (oxide film) on the corrosion-resistant steel plate and the formation of a new Cr-based oxide film are performed simultaneously. It is the oxygen potential, the substrate heating temperature, and the bias voltage in the vacuum chamber for the ion bombardment that determine the rate of such competitive reaction. By optimizing these factors, it is possible to change the composition of the oxide film formed on the surface of the corrosion-resistant steel plate formed during the ion bombardment treatment to form an oxide film mainly containing Cr.

That is, the oxidation potential in the vacuum chamber is optimized by setting the H ₂ O partial pressure in the vacuum chamber in which a non-oxidizing atmosphere gas is introduced to 2 × 10 ⁻⁴ to 8 × 10 ⁻⁶ Torr. It is possible to control the temperature and the bombarded state during the H ₂ O treatment by heating the substrate to 150 ° C. or higher and 500 ° C. or lower and applying a bias voltage of −20 to −400 V.

By applying the pretreatment method of the present invention, it is possible to uniformly form an oxide film having a thickness of about 200 to 300 Å on the surface of the corrosion-resistant steel plate. Furthermore, by heat treatment under the condition that Si and Cr-based oxides are formed after vapor deposition, Ti, Nb, without degrading the high corrosion resistance of the Cr-based oxide scale layer generated during ion bombardment treatment,
Since the diffusion of Cr further improves the adhesion of the vapor-deposited material, the corrosion resistance of the vapor-deposited steel sheet exhibits significantly better corrosion resistance behavior and film adhesion than the vapor-deposited steel sheet treated by the conventional method. Next, the reason why the steel composition of the austenitic stainless steel as the material to be treated and the ion bombardment treatment conditions in the present invention are limited as described above will be described.

(A) Components contained in stainless steel (1) C: C is a strong austenite stabilizing component,
It is desirable to include at least 0.01% or more, but 0.06%
If it is contained in excess of 10%, the sensitization tends to occur due to the precipitation of chromium oxide at the grain boundaries during heat treatment, so the content was set to 0.01 to 0.06%.

(2) Si: Si is a component having a function of deoxidizing, as well as having a function of concentrating on the surface of a steel material when heat-treated at a low dew point and improving the corrosion resistance of the surface. However, if its content is less than 0.1%, a sufficient deoxidizing effect cannot be obtained, and
%, The workability of the steel material is significantly deteriorated, so the content was made 0.1 to 5.0%. Further, in the case of the present invention, an oxide layer mainly composed of SiO ₂ is formed at the time of the heat treatment under the oxide layer mainly composed of Cr formed by the plasma treatment, which has an effect of improving the corrosion resistance. Moreover, 0.1% or more of Si is necessary because an oxide layer mainly composed of SiO ₂ is formed in the pinhole defect portion.

(3) Cr: The Cr concentration in steel is extremely important because it directly affects the composition of the surface oxide layer formed during the ion bombardment treatment. The Cr atoms involved in the oxide layer formation generated during the ion bombardment treatment are greatly affected by the Cr atoms already present near the outermost surface layer at the initial stage of the ion bombardment treatment. This is because the ion bombardment treatment time is short and the temperature is not a temperature at which thermal diffusion sufficiently progresses.
According to the results of repeated studies by the present inventors, the lower limit Cr concentration is 8% by weight. On the other hand, when Cr is contained in excess of 35.0%, the steel material becomes brittle and manufacturing becomes difficult. Therefore, its content is set to 8.0 to 35.0%.

(4) Ni: Ni has a function of stabilizing the austenite layer and enhancing the corrosion resistance, and is a component necessary for securing the corrosion resistance of the surface of the base material as in the case of Cr. The optimum content varies depending on the relationship between the Cr content and the N content, but if the content is at least 7.0%, the corrosion resistance of the base metal surface can be secured. However, Ni is an expensive component, and since the corrosion resistance is not further improved even if the added amount is increased more than necessary, the upper limit content is set to 50.0%.

(5) N: N is also a strong austenite-forming element and has an effect of enhancing corrosion resistance. Therefore, when higher corrosion resistance is required, an austenitic stainless steel material containing N in addition to the above components is used as a mother material. You may use it for wood. However, when the content of N exceeds 0.3%, Cr nitrides are formed and the corrosion resistance is deteriorated, so the content is 0.3%.
The following is recommended.

(6) Ti and / or Nb: Ti and Nb have the effect of stabilizing C in steel and preventing sensitization during heat treatment. In addition, Ti and Nb existing in the base material are diffused to the interface between the stainless steel material and the surface oxide film formed during etching and the vapor deposition film by applying an appropriate heat treatment, and the adhesion of the vapor deposition film is further improved. .. If the Ti and Nb contents are each less than 0.001%, a remarkable effect cannot be obtained. Also Ti
If the content exceeds 2.0%, the occurrence of surface defects during processing becomes remarkable and pinhole defects in the plated film after vapor deposition plating due to surface defects increase, so the Ti content is 0.001 to 2.0%.
I decided.

Further, Nb has a feature that defects and pinhole defects are smaller than Ti. However, its corrosion resistance is slightly inferior to that of Ti, so if it exceeds 2.0%, the corrosion resistance after heat treatment may deteriorate slightly. Therefore, the Nb content is set to 0.001 to 2.0%. The austenitic stainless steel material of the base material, Mo, Cu, M contained in the general austenitic stainless steel material in addition to the above components
It may contain components such as n and Al. The inclusion of these components does not affect the film adhesion and corrosion resistance of the vapor deposition material. It should be noted that the impurity S not only deteriorates the corrosion resistance but also segregates between the base material and the vapor-deposited film during the heat treatment and deteriorates the adhesion of the vapor-deposited film.
It is desirable to keep it below 0.03%. P is an impurity and is contained as an unavoidable impurity in refining in an amount of 0.10% or less.
It is usually 0.015 to 0.03%.

(B) Pretreatment conditions (1) H ₂ O partial pressure in the vacuum chamber: The H ₂ O partial pressure in the vacuum chamber is extremely important because it is related to the dew point in the vacuum chamber. In general, the oxidation behavior of metallic materials can be predicted from thermodynamic equilibrium calculations, but the oxidation during vapor deposition proceeds when the water molecules themselves are plasmatized while the gas molecules and metal atoms that are plasmatized are directly involved. Conceivable. Therefore, it is difficult to predict the oxidation behavior from mere thermodynamic equilibrium calculations.

The inventors of the present invention carried out a vacuum vapor deposition or an ion plating, and carried out a detailed evaluation by repeating the substrate surface analysis after the ion bombardment treatment and the substrate corrosion resistance evaluation after the vapor deposition, and evaluated the H ₂ in an appropriate vacuum chamber. O partial pressure was determined. When the H ₂ O partial pressure in the vacuum chamber is higher than 2 × 10 ^-4 Torr, the oxide film formed on the surface of the corrosion-resistant steel plate is an oxide film mainly composed of Fe regardless of the other controlling factors mentioned above. The deterioration of the corrosion resistance of the vapor deposition material becomes remarkable due to the deterioration of the corrosion resistance of the pre-deposition substrate itself. For example, in the case of Ti vapor deposition, the corrosion resistance was significantly deteriorated compared to the vapor deposition substrate due to the influence of corrosion of dissimilar metals.

On the other hand, the partial pressure of H ₂ O in the vacuum chamber is 8 × 10 ^-6 Torr.
Under lower conditions, a dense Cr oxide-based oxide film could not grow sufficiently on the corrosion-resistant steel plate substrate, and a stable corrosion-resistant effect was not recognized. Therefore, the H ₂ O partial pressure in the vacuum chamber should be 2 × 10
^-4 to 8 × 10 ^-6 Torr. However, here the H ₂ O in the vacuum chamber
The partial pressure is defined as the H ₂ O partial pressure in the vacuum chamber, which is a value measured by using a vacuum gauge and a mass spectrometer together. The inside of the vacuum chamber is set to a non-oxidizing atmosphere. For that purpose, Ar gas, N ₂ gas, H ₂ gas, and non-oxidizing gas mainly containing H ₂ may be used.

(2) Substrate heating temperature: In order to form an oxide layer mainly composed of Cr oxide on the surface within a short ion bombardment treatment time, the substrate should be preheated before the ion bombardment treatment. is important. Substrate heating temperature is
If the temperature is lower than 150 ° C, the amount of water adhering to the surface of the vapor deposition substrate cannot be sufficiently removed and stable performance cannot be obtained.
By setting the temperature to 150 ° C. or higher, water adhering to the substrate surface can be scattered and a stable and good effect can be obtained. In order to proceed the etching and oxidation reactions simultaneously and competing in the ion bombardment process, 150 ℃
It is important to preheat above 500 ° C.

If the substrate preheating temperature is higher than 500 ° C., the surface oxidation at the time of raising the temperature until the ion bombardment process starts cannot be ignored, and the subsequent ion bombardment process cannot be performed well. Diffusion movement on the substrate side during processing becomes remarkable, Fe oxidation progresses, and it becomes difficult to form a surface oxide layer mainly composed of Cr oxide with good corrosion resistance. Therefore, the substrate preheating temperature should be 150 ° C or higher.
The temperature was set to 500 ° C or lower.

(3) Substrate applied bias voltage: The bias voltage applied during the ion bombardment treatment is large in the removal rate of the oxide film on the surface of the corrosion-resistant steel plate, the growth rate of the oxide film formed at the same time as the removal, and the surface property after the treatment. affect. If the bias voltage during ion bombardment is less than -20V, surface etching does not progress effectively. Further, when the bias voltage exceeds -400V, the etching is so severe that the surface of the substrate is roughened, which is a cause of vapor deposition defect induction. Further, since the etching progresses violently, the temperature rise of the corrosion-resistant steel plate substrate becomes remarkable, and it becomes difficult to control the surface temperature.
Therefore, the bias voltage is set to -20V or more and -400V or less.

The Cr-based oxide film layer formed during the ion bombardment process will be described. The oxide film produced in the present invention is not simply a high temperature oxide film, but an oxide film produced in plasma. As is well known, the gas or metal in the plasma state is in an extremely active state, and unlike the general high temperature oxide film that accompanies thermal diffusion, thermal diffusion on the material side cannot be expected so much. It can be said that it is an oxide film formed. Cr oxides are mainly Cr ₂ O ₃ and Cr
It seems that Fe ₂ O ₃ etc. are generated.

Detailed examination of the oxide film layer formed in the present invention is a future subject, but the corrosion resistance of the Cr-based oxide film formed in the present invention is extremely good. It has been confirmed experimentally that it has various effects. The material to be pretreated in this way is then subjected to vapor deposition plating by a conventional method, and heat treatment is carried out after completion of plating.

(C) Heat treatment conditions (1) Furnace atmosphere Excellent corrosion resistance generated by ion bombardment pretreatment
In order to improve the adhesion by promoting the diffusion of Ti, Cr, Nb, etc. at the deposited film-base material interface without deteriorating the oxide film mainly composed of Cr oxide and the deposited film, the atmosphere in the furnace should be low oxygen. Since it is necessary to have a potential, the atmosphere in the furnace was a non-oxidizing atmosphere. If the furnace and non-oxidizing atmosphere, ammonia decomposition gas (AX gas), H ₂ -N ₂ mixture gas, hydrogen gas, CO gas, may be used Ar gas or the like, even if evacuated furnace Good.

(2) In-furnace dew point It is necessary to lower the in-furnace dew point as much as possible in order to prevent deterioration of corrosion resistance due to the inclusion of Fe oxide in the oxide film formed in the pretreatment. It is easy to determine the dew point in the furnace by calculating the oxidation potential of the components in steel, but it is not always the case in an actual furnace. The inventor conducted a study using an actual furnace and found that the corrosion resistance of the plated stainless steel had a corrosion resistance equal to or higher than that before the heat treatment when the dew point was -15 to -55 ° C. When the temperature is lower than −55 ° C, an oxide film is not sufficiently formed to improve the corrosion resistance, and when the dew point is higher than −15 ° C, the Fe oxide increases in the oxide film, and the corrosion resistance of the vapor-deposited plated material deteriorates significantly. Becomes Therefore, dew point
It was set at 15 to -55 ° C.

(3) Treatment temperature and treatment time When the treatment temperature of the heat treatment is lower than 500 ° C., diffusion of Ti, Cr, and Nb is very slow, and the effect of improving adhesion is not seen. Again 11
If the temperature exceeds 50 ° C, diffusion of the vapor deposition material to the base material side becomes remarkable, and desired performance cannot be secured. Alternatively, the mechanical properties on the base material side are deteriorated. Therefore, the heat treatment temperature of the plated stainless steel material was set to 500 ° C to 1150 ° C.

The amount of diffusion of Ti, Cr and Nb is determined by the treatment time, but if the diffusion time is less than 0.5 min, the diffusion of Ti, Cr and Nb is not sufficient, so the treatment time was set to 0.5 min or longer. In the present invention, the upper limit of the processing time need not be particularly limited. But 1000min
It is preferable to stop the treatment within 1000 min because further improvement in corrosion resistance and adhesion cannot be expected even if the treatment is performed for more than 10 minutes. Here, the "steel material" in the present invention includes not only steel plates but also other pipe materials, rod materials, shape materials and the like. Next, the present invention will be described more specifically with reference to Examples.

Example 1 Various steel plates having the compositions shown in Table 1 were used as vapor deposition substrates after degreasing and cleaning with an organic solvent. The vapor-deposited substrate was subjected to an etching treatment as a pretreatment under the conditions summarized in Table 3 and then subjected to a hollow cathode ion plating method.
Ti plating and TiN plating were applied. Ti plating film thickness is 0.2 μ
m, TiN plating film thickness was 1.0 μm. The voltage between the cathode of the hollow cathode plasma electron gun and the molten metal of the deposition material was 90 V, and the cathode current density was 250 A. After the vapor deposition, heat treatment was performed in a furnace in an ammonia decomposition gas atmosphere under the conditions of a furnace dew point of −49 ° C., a processing temperature of 930 ° C., and a processing time of 1.5 min.

The vapor deposition plated material thus obtained was evaluated for performance under the following conditions. The results are summarized in Table 2. Further, the concentrations of Cr, Fe and O in the vicinity of the surface of the austenitic steel substrate, which was pretreated only without Ti, TiN vapor deposition and subsequent heat treatment, were analyzed by secondary ion mass spectrometry (SIMS).

Table 3 shows the pretreatment conditions, and FIGS. 1 to 3 show the analysis results. Figure 1 shows the case without pretreatment
(No. 17), FIG. 2 shows the case where the pretreatment is performed according to the present invention (No. 17).
18), and FIG. 3 shows the element concentration distribution with respect to the sputtering time when the pretreatment conditions deviate from those of the present invention (No. 19).

Evaluation of Corrosion Resistance Corrosion resistance was evaluated by a salt spray test using a 10% NaCl aqueous solution. The salt spray conditions are 2000 hours and 50 ° C. continuous spray. The n number was evaluated at 5. The judgment was performed by observing the appearance with a magnifying glass of 25 times. Table 4 shows the judgment criteria.

Adhesiveness of deposited film The adhesiveness was evaluated by the adhesiveness of a deposited film at a bent portion of 180 ° C. at 1 t. The crack at the bent portion and the adhesion were evaluated using an optical microscope. No cracking was rated as ⊚, partial cracking was rated as ○, cracking was observed on the entire surface as △, and cracking and peeling were rated as x.

Example 2 The vapor deposition plated material of No. 15 prepared in Example 1 was heat-treated under various conditions. The same performance evaluation as in Example 1 was performed on the vapor-deposited plated material thus obtained.
The results are summarized in Table 4. From the results shown in Tables 2 and 4, it can be seen that the vapor-deposited steel sheets plated after being subjected to the pretreatment and the posttreatment by the method of the present invention have excellent adhesion and corrosion resistance.

On the other hand, in the comparative examples in which the steel composition of the substrate, the pretreatment conditions, and the posttreatment conditions deviate from the ranges specified in the present invention, either one or both of the adhesion and the corrosion resistance are inferior. ing.

Further, it can be seen from FIG. 1 that an oxide film mainly containing Cr is grown on the surface of the austenitic stainless steel sheet pretreated by the method of the present invention as compared with the stainless steel sheet before pretreatment. Moreover, the Cr concentration in the oxide film is extremely increased. On the other hand, in the comparative example in which the pretreatment deviates from the range defined by the present invention, no growth of the oxide film is observed, and it can be seen that the Cr concentration in the oxide film is remarkably reduced as compared with that before the pretreatment. ..

[0041]

[Table 1]

[0042]

[Table 2]

[0043]

[Table 3]

[0044]

[Table 4]

[0045]

[Table 5]

[0046]

According to the present invention, the adhesion of the vapor-deposited plating film is improved, and the corrosion resistance of the oxide film itself is greatly improved by increasing the Cr concentration in the oxide film on the surface of stainless steel.

[Brief description of drawings]

FIG. 1 is a graph showing the results of Examples.

FIG. 2 is a graph showing the results of Examples.

FIG. 3 is a graph showing the results of a comparative example.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁵ Identification code Office reference number FI technical display location C23F 4/00 C 8414-4K // C21D 1/76 G

Claims (1)

[Claims] 1. By weight%, C: 0.01-0.06%, Si: 0.1-
5.0%, Cr: 8.0 to 35.0%, Ni: 7.0 to 50.0%, N: 0.3% or less, and Ti: 0.001 to 2.0% and / or Nb: 0.001
When vapor deposition plating an austenitic stainless steel material containing ~ 2.0% as a substrate, a non-oxidizing atmosphere with a H ₂ O partial pressure of 2 x 10 ^-4 to 8 x 10 ^-6 Torr prior to vapor deposition plating The substrate should be heated to 150 ° C or higher in a vacuum chamber containing gas.
While preheated to 500 ° C or less, a bias voltage of -20 to -400V was applied to perform an ion bombardment treatment to generate an oxide film mainly composed of Cr oxide on the substrate surface, and further vapor deposition plating was performed. Later, in a furnace with a non-oxidizing atmosphere maintained at a dew point of -15 to -55 ° C, the temperature range was set to 500 to 1150 ° C.
A method for producing a corrosion-resistant vapor-deposited steel material, characterized by holding for 0.5 min or more.