JPH09272990A - Inhibitor of corrosion or the like in metal surface and method for inhibiting corrosion or the like - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively inhibit corrosion or corrosion cracking in the surface of a metal from occurring by using a blend of an organic or inorganic coating film forming material and grainy titanium dioxide as a corrosion inhibitor. SOLUTION: In the method using this inhibitor 1, grainy titanium dioxide is adopted on account of its good corrosion resistance and corrosion cracking resistance and the surface of a base material K made of a metal or the like is coated with the inhibitor 1 to form a coating layer of the inhibitor 1 on the surface of the base material K. At this time, a film forming material 3 is interposed between every adjacent two of grains 2 of the titanium dioxide so that every adjacent two of the grains 2 are not joined to each other and each of the grains 2 is disposed at a position independent from the other to form the coating layer of the inhibitor 1. Therefore, when a change in temp. is caused, each of the grains 2 is expanded or contracted independently from the change in volume of the base material K to prevent any swelling or cracking of the coating layer of the inhibitor 1 due to the difference in thermal expansion coefficient between the base material K and each of the grains 2 from occurring. If there is any recessed part K1 in the surface of the base material K, the recessed part K1 can be filled with the inhibitor 1 by a coating or injection method. The coating of the surface of the base material K with the inhibitor 1 can more easily be performed in a shorter time as compared with a conventional thermal spraying process or the like. Thus, any recessed part in a state subjected to pitting corrosion such as sulfide corrosion can easily and surely be filled with the inhibitor 1, and accordingly, an equipment in a state subjected to pitting corrosion can be repaired with the inhibitor 1.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an inhibitor for metal surface corrosion, sulfide corrosion cracking, hydrogen-induced cracking, and the like, and improvement of a method for preventing corrosion and the like.

[0002]

2. Description of the Related Art Conventionally, various experiments have been conducted on the selection of materials for metal structures in a wide range of corrosive environments, and structural materials suitable for the environment of use have been used. Then, in order to prevent the effect of welding residual stress on the corrosion when manufacturing the equipment, heat treatment for stress removal, addition of a neutralizing agent of corrosion inhibitor for protection of equipment, cathodic protection, pH adjustment are applied, In addition, measures and improvement measures have been studied to adapt to the assumed corrosive environment, such as the use of corrosion-resistant clad materials or passivation treatment for environmental protection. In practical equipment, many measures have been considered such as process change for corrosion suppression and equipment expansion.However, in actual equipment, corrosion thinning and stress corrosion cracking are the aging process after operation and use of equipment. And the corrosion factors include hydrogen sulfide, naphthenic acid, hydrogen, etc. in the petroleum production process and the effect of dew condensation. For example, in a refining device or a combustion device made of a metal material using a raw material containing a sulfur content such as petroleum, heavy oil, and coal, factors such as sulfide corrosion, sulfide corrosion cracking, and hydrogen-induced cracking occur, so that low temperature environment In, lead lining (homogen method), acid resistant mortar cement (castable), rubber, FRP resin lining, aluminum spraying, etc. are used. But,
The environment for using petroleum, coal, and refining equipment is the production of organic solvent-based substances, combustion and cooling of sulfur-containing components, refining (SO ₂ , H ₂ O,
In the manufacturing process of (H ₂ S, H _2, etc.), the corrosive environment fluctuates minute by minute. Therefore, it is difficult to completely shield the environment. In addition, lead lining and homogen have a decrease in the number of processing engineers and a limit in corrosion resistance and heat resistance in view of the environmental safety of processing work. Further, the aluminum lining or the aluminum spraying is influenced by the pH value of the environment in which it is used, and has a limit in its corrosion resistance. Therefore, Cr is used as the device material.
Steel, Cr-Mo steel, 18Cr-8Ni steel and the like, and synthetic clad steels thereof have been used. However, after several years of operation after construction, the expansion of corrosion cracks such as sulfide corrosion cracking and hydrogen induced cracking, especially starting near the weld, has occurred. As a suitable anti-corrosion measure for existing equipment, in addition to corrosion inhibitors, plate-like welding of food materials and cement lining where the base material has a heat effect on steel plates for high-pressure containers, such as chrome manganese steel and chrome molybdenum steel. It is not possible to use stud welding etc. The reason is that if the existing base material is locally affected by heat, the base material defects affected by sulfide and hydrogen will further expand. Therefore, the existing device has become disposable and a method of newly manufacturing the device has been adopted. On the other hand, it has been reported that applying a thermal spray coating of titanium dioxide (TiO ₂ ) is effective as a method for preventing hydrogen-induced cracking in such petroleum refining equipment. However, it is difficult to apply the thermal spray coating in the field etc. easily because it requires equipment and technology. In the case of radiation, when the operating temperature becomes higher (about 80 ° C or more), it becomes 1 in the sulfide corrosive environment.
There is a risk of swelling, cracking, and oxidation pattern of the thermal spray coating within a year to less than 3 years. This is because when the base material K and the sprayed coating b, for example, the carbon steel base material K is applied with the titanium dioxide sprayed coating b, the spray particles b1 ... b1 are struck in a molten state on the surface of the carbon steel during spraying. The sprayed coating layer b in which the grains are continuously bonded to each other is formed, and as shown in FIG.
It is considered that one of the factors is that there is a difference between the coefficient of thermal expansion b1 and the coefficient of thermal expansion K1 of the iron material, which causes a difference in volume change due to the difference in coefficient of thermal expansion. As a preventive measure, it is conceivable to provide a buffer layer of a coating composed of undercoating or intermediate spraying between the sprayed coating layer b and the base material K, but if the undercoating or intermediate spraying is performed, it is possible to further work. Is difficult and time consuming. Further, in the case of the above thermal spraying, as shown in FIG.
When the initial thermal spraying is performed on the base material K in a pitting corrosion state in which a plurality of small-pit-shaped concave portions K1 are formed due to sulfide corrosion or the like, the base material surface state is visually similar to that before the thermal spraying. Recess K
Exhibits a pitting corrosion condition with 1. On the other hand, when inspecting the oil refining equipment for corrosion or cracks, for example, if pitting corrosion is found, a method of removing a foreign substance in the recess K1 with a scraper, a metal rod, a knife or the like is adopted every time the inspection is performed. . Therefore, for example, if a person who does not know the surface condition of the base material before the thermal spraying is inspected, the thermal spray coating is normal and good, but the equipment environmental substance is deposited in the concave portion K1 and the appearance of corrosion pitting is apparent. Since it is confused with (trace), it is visually observed as if corrosion pitting corrosion has progressed. As a result, when inspecting the coating, foreign substances in the recess K1 are removed by a scraper, a metal rod, a knife or the like, and there is a concern that an inspector may damage the sprayed coating in the recess K1. Further, in this case, if the accumulated foreign substance is left as it is, the influence of corrosion concentration on the recess K1 is increased, which also causes the progress of corrosion on the recess K1.

[0003]

SUMMARY OF THE INVENTION The present invention has been proposed in view of the above circumstances, and prevents the metal surface corrosion of metal equipment used in an atmosphere where metal surface corrosion easily occurs. The purpose is to provide a chemical agent and a method for preventing corrosion.

The present invention is particularly applicable to metal surface corrosion that can easily and reliably prevent sulfide corrosion or sulfide corrosion cracking and hydrogen-induced cracking of metal equipment used for refining or burning petroleum, coal, coke and the like. It is an object of the present invention to provide such an inhibitor and a method for preventing corrosion.

[0005]

The preventive agent for metal surface corrosion and the like according to the present invention is a mixture of an organic or inorganic film forming agent and granular titanium dioxide.

Titanium dioxide has hitherto been known as a material having good corrosion resistance and corrosion cracking resistance, and this titanium dioxide functions as an inhibitor for corrosion and corrosion cracking. In the present invention, a granular material is used. When used in a granular form, when the particles are coordinated on the surface of the base material K as an object to be used as shown in FIG. The two layers of the inhibitor 1 are entirely coordinated independently of each other without being connected to each other. Therefore, when the temperature of the environment changes, the particles 2 ... 2 can expand and contract independently of the volume change of the base material K, and swelling or cracking of the film due to the difference in thermal expansion coefficient from the base material as in the case of thermal spraying. Can be prevented.

The size of each particle 2 of titanium dioxide is not particularly limited, and for example, those having a particle size of about 0.3 to 50 μm are commercially available.
It is preferable to use a material having an amount of not more than about this because the base material K can be easily inserted into the concave portion K1 in a pitting corrosion state due to sulfide corrosion or the like. In order to obtain such small-sized granular titanium dioxide having a particle size of about 10 μm or less, titanium dioxide is added to 10 μm in the same manner as in the case of spraying titanium dioxide on a metal surface.
It is sprayed in water by making it into small particles of less than about the size. As a result, the sprayed titanium dioxide particles are cooled by water, and round particles having a size of about 10 μm or less are obtained.

The film forming agent 3 is for forming a film on the surface of the base material K and adhering it to form granular titanium dioxide in a layered manner on the surface of the base material. Any material can be used as long as it can cope with the expansion and contraction of the base material K due to changes, and organic synthetic resin, inorganic sodium silicate, inorganic ethyl silicate, or the like can be used. Examples of the organic synthetic resin include epoxy resin, phenol resin, silicone resin, vinyl chloride resin, thermoplastic phenol resin, fluorine resin, furan resin, and the like, and one or two selected from these. Combinations of more than one species can be used.

The inhibitor 1 composed of the film forming agent 3 and the titanium dioxide 2 is formed as follows. First, granular titanium dioxide is put into a solvent containing an organic synthetic resin or an inorganic film forming agent 3 such as sodium silicate, and the mixture is obtained by mixing and stirring. The mixing ratio of the film forming agent 3 and the titanium dioxide 2 is 90 to 40 titanium dioxide with respect to 10 to 60% of the film forming agent.
%, And more preferably 90% titanium dioxide to 10 to 40% film-forming agent.
The blending volume is about 60%. When titanium dioxide is 40% or less with respect to the film forming agent, the effect of preventing corrosion, corrosion cracking, or hydrogen-induced cracking becomes difficult to be exhibited.
On the other hand, if it exceeds 90%, the viscosity will increase,
It may be difficult to apply. On the other hand, when it is 90% or more, the coefficient of thermal expansion as a whole depends on titanium dioxide, and as a result, the difference from the coefficient of thermal expansion of the base material K becomes large, which is not preferable. For example,
Thermal expansion coefficient 4 as a whole when an inhibitor is formed with a compounding volume of about 20% silicon resin and 80% titanium dioxide
Is shown in FIG. FIG. 2 is a diagram showing the thermal expansion coefficients of various thermal spray coatings and iron materials. In FIG. 2, the thermal expansion coefficient 4 of the inhibitor of the present invention is also shown.
The thermal expansion coefficient 4 of the inhibitor of the present invention is close to the thermal expansion coefficient K1 of the iron material as shown in FIG.
It is close at the high temperature of 0 ° C. Therefore, there is no difference in the volume change between the base material K made of steel and the inhibitor even at high temperature, and it is possible to prevent the inhibitor from being swollen, cracked, or oxidized due to the volume change. The coefficient of thermal expansion 4 of the inhibitor can be adjusted by changing the compounding ratio of titanium dioxide, and can be decreased by decreasing the compounding ratio of titanium dioxide, for example, and can be adjusted according to the substrate. Further, the coefficient of thermal expansion 4 when the above-mentioned other resin is used instead of the silicone resin is substantially the same as that of the silicone resin.

The above mixing ratios are the same whether an organic synthetic resin such as an epoxy resin is used as the film forming agent 3 or an inorganic sodium silicate or ethyl silicate is used.

When an epoxy resin is used, the temperature is 80 ° C or lower, when a phenol resin is used, the temperature is 200 ° C or lower, and when a silicone resin is used, the temperature is 550 ° C or lower. It is preferably used below. On the other hand, when the inorganic sodium silicate is used, it is preferably dissolved or deteriorated in the above organic resin at a use environment of 550 ° C. or lower, and is preferably used at 500 ° C. or higher. The viscosity of the inhibitor is not particularly limited as long as it can be applied to the surface of the substrate, and can be appropriately changed according to the use conditions.

The method of preventing corrosion of a metal surface according to the present invention prevents corrosion, corrosion cracking, hydrogen-induced cracking, etc. of a metal surface by directly applying the above-mentioned inhibitor in a fluid state. It is a thing.

The invention of the present application is not limited to the case where a base material K such as a metal device is newly manufactured and applied to the base material K in advance before being installed at a predetermined position, and it is already installed and movable at a predetermined position. It is applied and used as a repair at the time of inspecting the base material K. In the case of applying as a repair, for example, the surface of the substrate K may be provided with a plating layer or a thermal spraying layer. In that case, the coating may be applied directly from the plating layer or the thermal spraying layer. Therefore, the present invention is not limited to the case where the surface of the base material K is a base, and is not limited to the case where a surface of the base material K is applied, such as a case where a plating layer, a sprayed layer such as aluminum sprayed or titanium sprayed is applied. Can be used for The surface of the base material before coating is preferably cleaned by removing impurities such as fats and oils.

The surface of the base material K may be coated with a brush or the like, but if it is difficult to enter the recess K1 due to the viscosity of the coating agent or the state of the recess K1 of the base material K, it is pressed with a spatula or the like. To do so. The coating thickness t is not particularly limited and can be appropriately changed depending on the environment, the substrate K to be coated, etc.
If it is about m or more, sulfide corrosion or sulfide corrosion cracking and hydrogen-induced cracking of metal equipment used for refining or burning petroleum, coal, coke, etc. can be prevented.

In this way, if the inhibitor is applied directly to the surface of the base material, no equipment or equipment is required,
Moreover, anyone can easily do it in a short time. or,
Even when the concave portion K1 is formed on the surface of the base material K due to corrosion, the metallic surface coating agent can be reliably filled in the concave portion K1 and repaired. Moreover, it can be formed into a smooth shape after coating, and it is possible to prevent the coating layer from being scratched by a scraper, a metal rod, a knife or the like during inspection.

The object of use of the present invention is a petroleum refining apparatus in which sulfide corrosion or sulfide corrosion cracking and hydrogen-induced cracking frequently occur, a liquefaction apparatus using coal as a main raw material, various chemical plants and coke. It is especially suitable for flexible ore equipment for iron making, boiler equipment such as thermal power generation using heavy oil, petroleum, and coal as combustion materials, but it is not limited to this and can be used as a corrosion or corrosion cracking inhibitor. It can be used for various metal products.

[0017]

EXAMPLES Examples of the present invention will be specifically described below.

Example 1

First, an inhibitor was prepared as follows.
Each varnish of epoxy resin, silicone resin, phenolic resin, vinyl chloride resin (a transparent liquid in which the resin component does not contain a pigment) has the composition shown in Table 1 below.
Make a variety of film-forming agents. Separately from these, titanium dioxide material is heated and melted, sprayed in distilled water, and dehydrated and dried to obtain fine particles of titanium dioxide (0.3 to 10 μm).
m) was produced, and then each varnish and fine particles of titanium dioxide were mixed and stirred at a mixing ratio shown in Table 1 to obtain four kinds of inhibitors 1a ... 1d (inhibitor NO1a in Table 1).
~ 1d). Further, an inorganic ethyl silicate liquid was produced using each liquid of ethyl silicate 28 and 40, and the titanium dioxide fine powder (0.3 to 10 μm) produced separately from this liquid was produced.
m) was mixed and stirred at a mixing ratio shown in Table 2 below to obtain an inhibitor (inhibitor NO1e in Table 2).

[0020]

[Table 1]

[0021]

[Table 2]

Next, SM400B (JIS G 311)
4) The width V of the shape shown in FIGS. 3 (A) and 3 (B) that simulates the base material of the existing field equipment having the corroded pits K1 of the existing field equipment is 20 mm, the length L is 100 mm, and the thickness H is 4). 5 mm test pieces of sample Nos. 1 to 10 by manufacturing a first test material in the form of a quadrangular prism having a thickness of 7 mm and applying the above-mentioned inhibitors 1a to 1e to the upper surface of the first test material to a thickness t of 30 μm. (Samples NO1 to NO5 in Table 5 and Samples NO6 to 6 in Table 6)
NO10, where samples NO1 and NO6 are coated with the inhibitor 1a, samples NO2 and NO7 are coated with the inhibitor 1b, samples NO3 and NO8 are coated with the inhibitor 1c, samples NO4 and NO9 Are coated with the inhibitor 1d, and samples NO5 and NO10 are coated with the inhibitor 1e). Similarly, in the shape shown in FIGS. 3A and 3B, the width V is 20 mm, the length L is 100 mm, and the thickness H is 9 mm.
mm square prism second test material is manufactured, and each of the above inhibitors 1a to 1e is applied to the upper surface of the second test material with a thickness t of 30 μm.
5 kinds of test pieces of sample NO11 to 15 (sample NO11 to NO15 in Table 7, where sample NO11 is the one coated with the inhibitor 1a, sample NO12
Are coated with the inhibitor 1b, sample NO13 is coated with the inhibitor 1c, sample NO14 is coated with the inhibitor 1d, sample NO15 is coated with the inhibitor 1e). A total of 10 types of test pieces were prepared.

Then, these corrosion and corrosion cracking tests are
Hydrogen-induced cracking test method (NACETM 0177-9
0, NACE = National Associate
onof Corrosion Engineers)
And hydrogen content measurement test by glycerin substitution method (NACE
TM 0177-90) and sulfide stress corrosion cracking test method (NACE TM 0177-90). The hydrogen-induced cracking test is a sample NO prepared by applying the above-mentioned respective inhibitors 1a ... 1e to the first test material.
1 to NO5 were used under the environmental conditions shown in Table 3 below. Also, the hydrogen amount measurement test by the glycerin substitution method is
Using the samples 1 to 6 prepared by applying the above inhibitors 1a ... 1e to the first test material, the test conditions were shown in Table 4 below. On the other hand, the sulfide stress corrosion cracking test method uses the samples NO11 to NO15 prepared by applying the respective inhibitors 1 to the second test material, and under the environmental conditions shown in Table 3 below, FIG. Test equipment 1
The load stress P (the yield stress of the test piece 11 was set to 0.
8 times) was applied to the test piece 11.

[0024]

[Table 3]

[0025]

[Table 4]

The above-mentioned tests were carried out, and for the hydrogen-induced cracking test and the sulfide stress corrosion cracking test, after the tests, the appearance of each sample was visually confirmed, and the defects were confirmed by the ultrasonic flaw detection test. Tables 5 and 7 below
Shown in each. The values measured in the hydrogen content measurement test by the glycerin substitution method are shown in Table 6 below.

[0027]

[Table 5]

[0028]

[Table 6]

[0029]

[Table 7]

Further, as a comparative example, the SM400B steel plate was formed into the same shape as the first test material as it was (Samples 16 and 17), and the same shape as the first test material was used. Hydrogen-proof induced cracked steel sheet (JIS
G 3103) as-is (Sample 18, 1)
9), SM400B steel sheet coated with 30 μm of epoxy resin containing no titanium dioxide (Samples 20 and 21),
SM400B steel sheet coated with 30 μm of vinyl chloride resin not containing titanium dioxide (Samples 22 and 23), S
M400B steel plate coated with 30 μm of silicon resin not containing titanium dioxide (Samples 24 and 25), SM40
0B steel plate coated with 30 μm of an ethyl silicate solution containing no titanium dioxide (Samples 26 and 27), SM4
00B steel sheet directly sprayed (Samples 28 and 29)
Comparative tests of the hydrogen-induced cracking test and the hydrogen content measurement test by the glycerin substitution method were conducted under the same conditions as above, and are shown in Table 5 and Table 7 below.

Further, the SM400B steel sheet was formed into the same shape as that of the above-mentioned second test material, and was left as it was (Sample 3
0), the same as the following, the same as that of the second test material, but the same as that of the hydrogen-resistant induced cracking steel sheet (Sample 31),
SM400B steel plate coated with 30 μm of epoxy resin containing no titanium dioxide (Sample 32), SM400B
30% vinyl chloride resin containing no titanium dioxide on the steel plate
μm coated (Sample 33), SM400B steel plate coated with 30 μm of silicon resin not containing titanium dioxide (Sample 34), SM400B steel plate coated with 30 μm of titanium dioxide-free Ethyl silicate solution (Sample 35) , SM400B steel sheet directly spray-coated (Sample 36) were prepared, and the comparative test of the sulfide stress corrosion cracking test was performed under the same conditions as described above.
It is shown in Table 6 below.

The results show that in the hydrogen-induced cracking test and the sulfide stress corrosion cracking test, as shown in Tables 5 and 7, those of the comparative examples (samples NO 16, 18, 20, 22, in Table 5;
Nos. 24, 26, and sample Nos. 28 to 33 in Table 7), blisters, cracks, pitting corrosion, spot rust, etc. were found in the appearance, and those obtained by spraying titanium dioxide in an ultrasonic flaw detection test (Sample 28,
Defects were observed except for 36). On the other hand, those coated with the inhibitor of the present invention (samples NO1 to NO in Table 5)
5 and samples No. 11 to No. 15) in Table 7, no abnormalities were found in the appearance, and no defects were found in the ultrasonic flaw detection test. On the other hand, in the hydrogen amount measurement test by the glycerin substitution method, as shown in Table 6, those of Comparative Example (Table 6
Sample No.17, 19, 21, 23, 25, 27)
Except for those sprayed with titanium dioxide (Sample 28),
A large amount of absorbed hydrogen was observed, but the one coated with the inhibitor of the present invention showed almost no absorbed amount of hydrogen. From the above results, the one coated with the inhibitor of the present invention was good in the hydrogen-induced cracking test, the hydrogen content measurement test, and the sulfide stress corrosion cracking test.

Embodiment 2

The gas gas discharged from the overhead of the atmospheric distillation unit of the petroleum refining apparatus is introduced into the gas absorption apparatus and contains LP gas, hydrogen sulfide and the like. Depending on the refining process of each device, the fuel gas and the waste gas are discharged. Is separated into Also, in the waste gas cleaning step, an amine-based neutralizing agent or the like is used to reduce the acid concentration. However, corrosion mist in fuel gas was locally or entirely deposited inside the equipment, and corrosion of sulfide and hydrogen-induced cracking and swelling of the base material were observed in a relatively low temperature portion of the equipment. Therefore, a simulated test piece coated with the inhibitor of the present invention was prepared, and the simulated test piece was inserted into a heating furnace (muckle furnace) and tested. This test uses the same simulated test piece as the sample NO2 in Table 5 used in Example 1 above (the test piece is coated with an inhibitor in which titanium dioxide is included in a silicon resin), Insert the simulated test piece into the heating furnace (Muckle furnace) at 250 ° C,
After maintaining for a minute, it was quenched during normal temperature distillation. This operation was repeated 50 times to perform a thermal shock test on the simulated test piece.
In addition, as the simulated test piece, the inhibitor in which the titanium dioxide is included in the silicon resin is used because the operating temperature is 250 °.
This is because C is taken into consideration. As a result, it was confirmed that there was no swelling of the inhibitor, deterioration of the silicone resin, and adhesion. In addition, the preventive agent implementation work on the existing actual equipment was inspected on-site at the time of regular inspection and opening every two years, but all the preventive agents are in good condition. After that, the number of years of effectiveness of the preventive agent will be used as the follow-up confirmation.

[0035]

As described above, the metal surface corrosion inhibitor of the present invention can effectively prevent corrosion and corrosion cracking in a corrosive environment. It can also prevent sulfide corrosion or sulfide corrosion cracking and hydrogen-induced cracking, and even at high temperatures,
It is possible to prevent swelling and cracking of the film due to the difference in thermal expansion coefficient from the base material. Therefore, it is suitable as an inhibitor for corrosion of the surface of metal equipment used for refining or burning petroleum, coal, coke and the like.

Further, the method of preventing corrosion of the metal surface of the present invention can be carried out easily and in a short time as compared with the conventional thermal spraying. In addition, by using an inhibitor containing granular titanium dioxide, titanium dioxide can be easily and surely filled in the concave portion in the pitting corrosion state due to sulfide corrosion, etc., and the equipment in the pitting corrosion state is repaired. be able to.

[Brief description of drawings]

FIG. 1 is a cross-sectional explanatory view of a state in which an inhibitor of the present invention is applied to a base material.

FIG. 2 is a line graph showing the thermal expansion coefficient of an inhibitor according to an embodiment of the present invention together with various thermal spray coatings and iron materials.

FIG. 3A is a cross-sectional view in which a part of a test piece in which the inhibitor of the present invention is applied to a test material is omitted, and FIG. 3B is a vertical cross-sectional view thereof.

FIG. 4 is an explanatory diagram of a test device used in a sulfide stress corrosion cracking test method.

FIG. 5 is a cross-sectional explanatory view of a conventional example in which a base material is sprayed.

[Explanation of symbols]

 1 inhibitor 2 particles of titanium dioxide 3 film forming agent K base material K1 recess

Claims (2)

[Claims] 1. A preventive agent for corrosion of a metal surface, which comprises an organic or inorganic film forming agent and granular titanium dioxide. 2. An inhibitor prepared by mixing an organic or inorganic film forming agent and granular titanium dioxide is prepared, and the inhibitor is applied to a metal surface in a fluid state. How to prevent metal surface corrosion.