WO2018061972A1

WO2018061972A1 - Surface-treated metal member and heating device

Info

Publication number: WO2018061972A1
Application number: PCT/JP2017/034078
Authority: WO
Inventors: 宏信今泉; 友希河野; 拓摩疋田
Original assignee: クリナップ株式会社
Priority date: 2016-09-30
Filing date: 2017-09-21
Publication date: 2018-04-05
Also published as: TW201819683A; TWI734838B

Abstract

[Problem] The purpose of the present invention is to provide a surface-treated metal member which is able to be prevented from discoloration due to oxidation for a long period of time even in a high temperature environment. [Solution] A surface-treated metal member wherein a coating layer 12 is formed on the surface of a metal layer 11. This surface-treated metal member is characterized in that: the metal layer 11 is composed of a stainless steel material containing aluminum; and the coating layer 12 is composed of a single layer containing a silicon compound, an aluminum compound or a zirconia compound. This surface-treated metal member is alternatively characterized in that: the metal layer 11 is composed of a stainless steel material containing aluminum; and the coating layer 12 comprises a first layer 21 that contains a silicon compound and a second layer 22 that is laminated on the first layer 21 and contains an aluminum compound.

Description

Surface-treated metal member, heating equipment

The present invention relates to metal members used for appliances exposed to direct fire at the time of heating such as cooking appliances such as gas stoves, grills, gotoku, lighters and pans, heater parts, drying and baking furnaces, stoves, exhaust pipes and boiler pipes In a metal member used in a high temperature environment such as, etc., a surface-treated metal member capable of effectively preventing the color change over a long period of time by preventing oxidation of the metal due to high temperature, and the same are used It relates to a heating apparatus.

Stainless steel has an extremely thin protective passivation film with a thickness of several nm to several tens of nm, and exhibits excellent corrosion resistance and heat resistance while maintaining a beautiful metallic gloss. For this reason, conventionally, heating appliances such as gas stoves, grills, Gotoku and gas burners that are exposed to direct fire at the time of heating, and devices used under high temperature environments such as heater parts, drying and baking furnaces, boiler piping and the like Used as a material to

However, this stainless steel may have a so-called temper color in which the surface is discolored and colored in a high temperature environment as described above. Such discoloration of stainless steel is based on the fact that the high temperature causes the stainless steel to be oxidized to form an oxide layer. When the thickness of the oxide layer matches the wavelength of light, the reflected light interferes and is recognized as a color difference. When such discoloration due to oxidation appears on the surface of stainless steel as a metal member, it gives an impression that the appearance and the designability are rapidly deteriorated. In particular, heating appliances such as Gotoku, gas stoves, gas burners, etc. may experience such discoloration even if they only touch the open flame, even though days have not passed since the time of purchase, and they are used up It gives an impression of being suddenly outdated.

For this reason, techniques capable of preventing discoloration due to oxidation of stainless steel in a high temperature environment have been studied conventionally. First, Patent Document 1 discloses a technology in which a reaction layer having a thickness of 5 to 100 nm is interposed between a steel base and an alkali silicate film in a stainless steel material having an alkali silicate film on the surface. Through this reaction layer, it is expected to suppress the diffusion of atoms to the alkali silicate film covering the steel surface, stop the formation of the Cr-Fe-O-based oxide layer which causes tempering color, and prevent the color change. It is

Patent Document 2 discloses a technique of forming a silicate compound film made of polysilazane on the surface of stainless steel. Since this silicate compound is an oxide in which the diffusion of oxygen is slow, it is expected to prevent discoloration by suppressing the progress of oxidation occurring near the surface of stainless steel.

Patent Document 3 discloses a technology of a gas barrier film using a silicon nitride film. A silicon nitride film deposited by chemical vapor deposition is transparent and has high gas barrier properties. The technology disclosed in Patent Document 3 is a technology for forming a transparent film having high gas barrier properties, and therefore, the effect of preventing oxidation can be expected by forming a film on metal.

Patent Document 4 discloses a technical idea in which an alumina thin film is used as an oxidation suppression film. The alumina thin film has excellent film formability, compactness, thermal stability, electrical insulation and the like, and is expected to prevent discoloration due to oxidation of stainless steel in a high temperature environment.

However, according to the disclosed technology of Patent Documents 1-4, although it is possible to prevent discoloration due to oxidation of stainless steel at high temperatures, the long-term use of high temperature gradually promotes the oxidation of the substrate, especially at 700 ° C. There is a problem that the durability to the temper collar is insufficient in the ultra-high temperature region where it exceeds.

Patent Document 5 and Patent Document 6 disclose a technique for suppressing oxidation by containing Al in stainless steel. Oxidation is surely suppressed by forming an oxide film derived from Al by containing Al in stainless steel, but its oxidation suppressing effect is limited to the prevention of oxidation amount increase and weakening by oxidation at high temperature, and high temperature It does not reach the point of preventing appearance discoloration in the environment.

Further, Patent Document 7 discloses a technique of coating an oxide layer made of a silica-based compound with a thickness of 1 μm or less on the surface of stainless steel. Since this silica-based compound is an oxide in which diffusion of oxygen is slow, it is expected to prevent discoloration by suppressing the progress of oxidation occurring near the surface of stainless steel.

However, according to the disclosed technology of Patent Document 7, although it is possible to prevent discoloration due to oxidation of stainless steel at high temperature, in the case of stainless steel used in an environment of 700 ° C. or more at the time of heating Discoloring can not be sufficiently prevented, and there is also a problem that appearance abnormalities other than discoloration due to oxidation such as cracking and whitening of the coating film can not be suppressed.

JP 2008-231551 A JP 2015-44300 A Japanese Patent Application Publication No. 2004-292877 JP 2013-216760 A Japanese Patent Application Laid-Open No. 2002-339048 Japanese Patent Application Publication No. 2005-504176 JP, 2006-63427, A

Accordingly, the present invention has been made in view of the above-mentioned problems, and the object of the present invention is to provide a surface-treated metal member capable of preventing discoloration due to oxidation in a high temperature environment for a long time, and This is to provide a heating device to be used. That is, an object of the present invention is to improve the durability of temper color suppression by a coating film.

In addition, the object of the present invention is to prevent discoloration due to oxidation even in a high temperature environment of 700 ° C. or more, and appearance abnormality other than discoloration due to oxidation such as cracking or whitening of the coating film or substrate It is an object of the present invention to provide a surface-treated metal member capable of preventing the deterioration of its corrosion resistance, as well as a heating device using the same.

The present inventors are surface-treated metal members in which a single-layer coating layer is formed on the surface of an aluminum-containing stainless steel material in order to solve the problems described above, wherein the coating layer is a silicon compound, an aluminum compound We have invented a surface-treated metal member containing any of the zirconium compounds, as well as a heating device in which it is used.

The surface-treated metal member according to the first invention is a surface-treated metal member having a coating layer formed on the surface of a metal layer, wherein the metal layer is a stainless steel containing aluminum, the coating layer is a silicon compound, It is characterized in that it comprises a single layer containing either an aluminum compound or a zirconium compound.

In the surface-treated metal member according to the second aspect of the present invention, in the first aspect, the coating layer contains any of a silicic acid compound as the silicon compound, an aluminum oxide compound as the aluminum compound, and a zirconium oxide compound as the zirconium compound. It is characterized in that it consists of a single layer.

The surface-treated metal member according to the third invention is a surface-treated metal member having a coating layer formed on the surface of a metal layer, wherein the metal layer is a stainless steel containing aluminum, and the coating layer is a silicon compound. It has a first layer to be contained, and a second layer laminated on the first layer and containing an aluminum compound.

In the surface-treated metal member according to the fourth invention, in the third invention, the first layer contains a silicate compound as the silicon compound, and the second layer contains an aluminum oxide compound as the aluminum compound. It is characterized by

In the surface-treated metal member according to a fifth aspect of the present invention, in the fourth aspect, the paint as the precursor of the first layer is a crystal particle dispersion liquid.

The surface-treated metal member according to the sixth invention is characterized in that, in any one of the first invention to the fifth invention, the coating layer exhibits transparency.

A heating apparatus according to a seventh invention is characterized in that it has a metal member to be heated, and the surface-treated metal member of any of the first to sixth inventions is used for the metal member.

According to the present invention configured as described above, the gas barrier properties of the silicon compound, the aluminum compound, and the zirconium compound constituting the coating layer can suppress the oxidation of the substrate. Further, according to the present invention, when aluminum is contained in the stainless steel forming the metal layer, discoloration due to oxidation can be detected with the naked eye when exposed to a high temperature environment for a long time to stainless steel not containing aluminum. It is possible to further prolong the time required to achieve so-called durability. The improvement of the durability has a remarkable effect which can not be inferred from the difference in durability against oxidation discoloration of the substrates.

Furthermore, according to the present invention, since the metallic gloss state can be maintained for a long time, it is possible to provide a heating device excellent in design.

Further, according to the present invention having the above-described configuration, it is possible to prevent appearance abnormality from occurring in a high temperature environment due to being located in the vicinity of a direct fire by the aluminum compound constituting the second layer. In addition to this, according to the present invention, the first layer functions as a barrier layer for the diffusion of the Fe element, so that the first layer can be prevented from being diffused inside the second layer. Therefore, oxidation itself by oxidation of Fe can not occur in the aluminum compound, and it is possible to prevent discoloration due to oxidation and to prevent discoloration due to corrosion even under a high temperature environment exceeding 700 ° C. it can.

Furthermore, according to the present invention, by containing aluminum in the stainless steel constituting the metal layer, the stainless steel not containing aluminum is provided with the first layer and the second layer of the present invention, or aluminum When exposed to a high-temperature environment over 700 ° C. for a long time, the time until the color change due to oxidation could be detected with the naked eye was significantly longer than in the case where the heat-resistant stainless steel contained is not coated. In this way, an effect of significantly improving the durability of preventing discoloration due to oxidation is produced.

It is a figure showing a heating implement to which a surface treatment metal member to which the present invention is applied is applied. It is a figure for demonstrating each layer which comprises the surface treatment metal member to which this invention is applied. It is a figure which shows the example which formed the coating layer in the upper layer of the metal member which comprises the surface of a gas burner. It is another figure for demonstrating each layer which comprises the surface treatment metal member to which this invention is applied.

First Embodiment A first embodiment of a surface-treated metal member to which the present invention is applied will be described in detail with reference to the drawings.

The first embodiment of the surface-treated metal member to which the present invention is applied is used, for example, for Vitoku 3 or the like as a heating appliance to which an open flame is exposed at the time of cooking as shown in FIG. Five virtues 3 are used for gas stove 2 in a system kitchen. There are many cases where Gotoku 3 is shaped like a nail that extends from the periphery of the gas stove 2 toward the center, and a heating container such as a kettle or a pan is placed. Gotoku 3 is often used in high temperature environments of 700 ° C or more because it is located in the vicinity of the open flame emitted from gas stoves, and is used in high temperature environments of 1000 ° C or more when exposed to direct fire Often

FIG. 1 (b) shows a cross-sectional view taken along the line B--B 'of the surface-treated metal member constituting such Vantoku 3. FIG. The surface-treated metal member constituting the Vittoku 3 includes a metal layer 11 as a base material thereof, and a coating layer 12 coated and laminated so as to cover the surface of the metal layer 11.

The metal layer 11 is made of, for example, a metal such as stainless steel. It is essential that the metal layer 11 contains aluminum among the stainless steels. Stainless steel forms an extremely thin protective high passivity film with a thickness of several nm to a few tens of nm by combining the added Cr with oxygen in the air. This passive film exhibits excellent corrosion resistance and heat resistance. That is, Vitoku 3 can prevent the occurrence of rust by the metal layer 11 on which the passive film is formed.

By the way, as an example of stainless steel constituting the metal layer 11, stainless steel containing at least aluminum is used. At this time, the content of aluminum with respect to the total weight of the stainless steel is not particularly limited, but is preferably, for example, 1 to 12% by weight, and more preferably 2 to 4% by weight.

The coating layer 12 is composed of a single layer containing any one of a silicon compound, an aluminum compound and a zirconium compound.

When the coating layer 12 is formed of a layer containing a silicon compound, an example of the silicon compound is a concept including all compounds having Si, for example, dehydrated and condensed silicon tetraethoxy And polysilazane, siloxane, silicate, silicon nitride, silicon carbide and the like. However, this silicon compound is not limited to these examples.

The coating layer 12, if it is constituted by a layer containing aluminum compound, Examples of the aluminum compound, Al ₂ O _3, aluminum nitride, mullite, spinel and the like. However, this aluminum compound is not limited to these examples.

When the coating layer 12 is formed of a layer containing a zirconium compound, examples of the zirconium compound include ZrO ₂ , stabilized zirconia, zircon, and the like. However, this zirconium compound is not limited to these examples.

The coating layer 12 is made of a material exhibiting transparency, so that the metallic color of the metal layer 11 covered by itself can be positively shown on the surface. However, it goes without saying that the coating layer 12 may be made of materials other than the material exhibiting transparency.

The silicon compound, the aluminum compound, and the zirconium compound that constitute the coating layer 12 function as a barrier layer that inhibits oxygen in the air from oxidizing the metal substrate, so that so-called tempering color is generated due to so-called oxidation discoloration. It is possible to prevent it.

The operation of Vitoku 3 having the surface-treated metal member having the above-described configuration will be described below. When the cooking container placed on Gotoku 3 is heated by the open fire by the gas stove 2, Gotoku 3 is located near the open fire, and in some cases the open fire will be in direct contact. As a result, Gotoku 3 will be placed in a high temperature environment exceeding 1000 ° C. Even when the direct fire is not touched, the high temperature environment of 700 ° C. or more is placed in the vicinity of the direct fire.

In such a case, the coating layer 12 can be prevented from being oxidized in a high temperature environment by inhibiting oxygen in the air from reaching the metal substrate through the silicon compound, the aluminum compound and the zirconium compound. It is possible to prevent the color change. Furthermore, by containing aluminum in the stainless steel constituting the metal layer 11, the stainless steel not containing aluminum is not coated with the coating layer 12 of the present invention or the heat-resistant stainless steel containing aluminum. When exposed to a high-temperature environment over 700 ° C. for a long time, the time until the naked eye could detect the discoloration due to oxidation became significantly long. In this way, an effect of significantly improving the durability of preventing discoloration due to oxidation is produced.

The present invention is applied to an object which is required to have high temperature durability although it is not directly hit, except when it is applied to a device such as Vitoku 3 which is directly hit by fire. The present invention is not limited to the case where it is applied to heating appliances such as gas stoves, grills, lighters, pans, etc. other than Gotoku 3, and any metal member used under high temperature environment is applicable. It may be For example, it is a matter of course that the present invention may be applied to a gas burner 5 as shown in FIG. 3, a heater part, a stove, an exhaust pipe, a boiler pipe and the like. Even in the gas burner shown in FIG. 3, the coating layer 12 is formed on the upper layer of the metal layer 11 constituting the metal member constituting the surface. And this metal layer 11 is comprised with the stainless steel material containing aluminum.

Further, according to the present invention, even if the coating layer 12 composed of any of a silicon compound, an aluminum compound and a zirconium compound is constituted by a single layer, the color change preventing effect due to oxidation can be achieved by covering the aluminum containing stainless steel material. It can be expressed. For this reason, the material cost is reduced as compared with the case where the coating layer 12 is configured with two or more layers, in particular if the purpose is to improve the durability of preventing discoloration due to oxidation in a place where direct fire does not occur. It is also possible to reduce the manufacturing labor by reducing the number of lamination steps, and hence to shorten the manufacturing time.

Further, the present invention is not limited to these, and may be applied to any device having a metal member heated to a high temperature. In such a case, the coating layer 12 is formed on the upper layer of the metal member made of stainless steel containing aluminum.

Hereinafter, experimental verification performed to confirm the effect of the surface-treated metal member to which the present invention is applied will be described in detail.

In this experimental verification, first, a plurality of samples were prepared as shown in Table 1, and a water pan discoloration test was conducted.

The samples are composed of only the metal layer 11, and Comparative Examples 1 to 4 in which the coating layer 12 is not laminated on the surface, and the coating layer 12 containing the above-described component on the metal layer 11 not containing aluminum Inventive Examples 1 to 7 in which the coating layers 12 containing the components described above are laminated on a single layer over the metal layers 11 containing aluminum, and the above-described examples on the metal layer 11 Comparative Examples 12 and 13 in which two coating layers 12 containing the above components are laminated.

The application amounts of the samples of Comparative Examples 1 to 11 and Inventive Examples 1 to 7 are approximately 1000 mg / m ² . The coating amounts of Comparative Examples 12 and 13 are approximately 1000 mg / m ² for the silicon compound-based film A and approximately 400 mg / m ² for the aluminum compound-based film.

In Comparative Examples 1, 2 and 5 to 12, stainless steel (SUS 304) containing no aluminum and stainless steel (SUS 430) containing no aluminum were used as the metal layer 11, and Invention Examples 1 to 7 and Comparative Example 2 were used. 3 and 13 are stainless steel (15Cr-4Al-LC, N) containing 4% by weight of aluminum as the metal layer 11 with respect to the total weight of the stainless steel, 2 weight as the metal layer 11 with respect to the total weight of the stainless steel % Stainless steel (18Cr-2Al-Ti) is used.

In Comparative Examples 5 and 6 and Inventive Examples 1 and 2, as the silicon compound main film A, a crystal dispersion liquid mainly made of silica having a concentration of 10% and an average diameter of 25 nm or more is applied as the coating layer 12.

In Comparative Example 7 and Inventive Example 3, polysilazane having a concentration of 20% is applied as the coating layer 12 as the silicon compound-based film B.

In Comparative Examples 8 and 9 and Invention Examples 4 and 5, an aluminum hydroxide nanoparticle dispersion having a concentration of 3% and an average diameter of 200 nm or more is applied as the coating layer 12 as an aluminum compound-based film.

In Comparative Examples 10 and 11 and Invention Examples 6 and 7, a zirconium nanoparticle dispersion having an average diameter of 10 nm or more is applied as the coating layer 12 as a zirconium compound-based film.

In Comparative Examples 12 and 13, the above-described silicon compound main film A is stacked directly on the metal layer, and the above-described aluminum compound main film is stacked directly on the silicon compound main film A.

The experimental verification by the water pan discoloration test was performed about each sample mentioned above. In the water pan discoloration test, a pot (24 cm in diameter) containing 2 liters of water was placed in a heater provided with Gotoku on which the coatings of Comparative Examples 1 to 13 and Invention Examples 1 to 7 were applied. Continuous heating with a high calorie burner was repeated for 1 hour, and the color change was visually evaluated according to JIS K 5600-4-3 (only light source uses LED (Ohm Electric LED PL 48 W)). About this water pan discoloration test, the floor surface wall was all white in a room (SCI value 90.61), and the illumination intensity of the observation position was about 2300 Lux.

In Table 1, a stainless steel (15Cr-4Al-LC, N) containing 4% by weight of aluminum as a representative of a metal not containing aluminum in the metal layer 11 as a representative of a metal containing aluminum is taken as an example. The discoloration prevention durability improvement effect in the aluminum containing metal was represented by magnification. This discoloration prevention durability improvement effect is
Color change prevention durability improvement effect = (Color change start time (h) in a specimen of stainless steel containing 4% by weight of aluminum) / (Color change start time (h) in a sample of SUS304)
Is represented by This anti-discoloring durability improvement effect is confirmed 3 times or more, and the anti-discoloring durability exceeding 310 h is ◎, the effect of the aluminum-containing substrate is confirmed 3 times or more, the anti-discoloring durability is less than 310 h As for ○, and the thing in which the effect of the aluminum containing base material is not confirmed was made into x, and comprehensive evaluation was performed.

In the water pan discoloration test, visual evaluation was performed under the conditions described above. First, in Comparative Examples 1 to 4, a water pot discoloration test was carried out in a state where the coating was not performed on SUS304 not containing aluminum, SUS430 and stainless steel containing 4% by weight of aluminum, and stainless steel containing 2% by weight of aluminum. The color change start time was measured. As a result, the color change initiation time was 2 minutes regardless of the substrate. From this, in the state which does not coat at all, the discoloration prevention durability improvement effect of an aluminum containing base material is not confirmed, but comprehensive evaluation became x.

Next, with respect to SUS304 and SUS430 which do not contain aluminum as comparative examples 5 to 7, stainless steel containing 4% by weight of aluminum as invention examples 1 to 3 and stainless steel containing 2% by weight of aluminum according to the invention examples Under the above coating conditions, the silicon compound-based film A and the silicon compound-based film B were coated, and each of them was subjected to a water pan color change test to measure the color change start time. As a result, although the color change start time of Comparative Examples 5 to 7 was all 110 hours, the color change was not confirmed even at 470 hours of all of Invention Examples 1 to 3.

From this, by laminating the coating layer 12 containing a silicon compound on the metal layer 11 containing aluminum, the effect of improving the discoloration prevention durability is at least as compared to the case where the coating layer 12 is laminated on the metal layer 11 not containing aluminum. The overall evaluation was ◎ because it was found to be 4 times or more, and the durability also exceeded 310 hours of Comparative Example 12 of the two-layer film having the highest color change prevention durability in the metal layer 11 not containing aluminum. .

Next, with respect to SUS304 and SUS430 containing no aluminum as Comparative Examples 8 and 9, a stainless steel containing 4% by weight of aluminum according to Invention Examples 4 and 5 and a stainless steel containing 2% by weight of Aluminum according to Invention Examples The coating of the aluminum compound-based film was performed under the coating conditions, and the water pan discoloration test was performed on each of them to measure the color change initiation time.

As a result, in Comparative Examples 8 and 9, the discoloration start time was 10 hours and 4 hours, respectively, but in each of Invention Examples 4 and 5, no discoloration was confirmed even at 145 hours. From this, by laminating the coating layer 12 containing the aluminum compound on the metal layer 11 containing aluminum, the effect of improving the discoloration prevention durability is at least as compared to the case where the coating layer 12 is laminated on the metal layer 11 not containing aluminum. Although it turned out that it becomes 14.5 times or more and the effect of the aluminum-containing substrate was confirmed, since the durability did not exceed 310 hours, comprehensive evaluation was ○.

Next, with respect to SUS304 and SUS430 containing no aluminum as Comparative Examples 10 and 11, stainless steel containing 4% by weight of aluminum according to Invention Examples 6 and 7 and stainless steel containing 2% by weight of Aluminum according to Invention Examples The coating of the zirconium compound-based film was performed under the coating conditions, and the water color change test was performed on each of them, and the color change start time was measured.

As a result, although the color change start time of each of Comparative Examples 10 and 11 was 45 minutes, the color change start time of each of Invention Examples 6 and 7 was 4 hours and 18 hours, respectively.

From this, by laminating the coating layer 12 containing a zirconium compound on the metal layer 11 containing aluminum, the discoloration preventing durability improvement effect is obtained as compared with the case where the coating layer 12 is laminated on the metal layer 11 not containing aluminum. Although it turned out that it becomes 5 times and the effect of the aluminum-containing substrate was confirmed, since the durability did not exceed 310 hours, comprehensive evaluation was ○.

Next, as Comparative Examples 12 and 13, with respect to SUS304 not containing aluminum and stainless steel containing 4% by weight of aluminum, the silicon compound A described above is laminated directly on the metal layer under the coating conditions of the example of the present invention. The coating on which the above-mentioned aluminum compound-based film was laminated was performed directly on the compound A, and a water pan color change test was performed on each of them to measure the color change start time.

As a result, the color change start time of Comparative Example 12 was 310 hours, and the color change start time of Comparative Example 13 was 1700 hours.

From this, by laminating the coating layer 12 having a two-layer structure of a coating layer containing a silicon compound and a coating layer containing an aluminum compound on the metal layer 11 containing aluminum, the metal layer 11 not containing aluminum is formed. Compared with when it laminated | stacked, it turns out that the discoloration prevention durability improvement effect will be 5.5 times, Since the durability also exceeds 310 hours, comprehensive evaluation became (double-circle).

Moreover, it evaluated also about the manufacturability. In the present invention example 1, the present invention example 3, the present invention example 4, the present invention example 6, in which the coating layer was laminated on the metal layer 11 (15Cr-4Al-LC, N) containing aluminum, respectively, the easiness of production was obtained. The comparative example 13 was evaluated. The evaluation index of manufacturability measures the time required to coat the coating layer and has the operator evaluate the burden of the actual coating labor in three stages, which prolongs the manufacturing time and burdens the manufacturing labor In the case where is large, x, the production time is medium, the burden of production labor is medium 中, the production time is short, and the burden of production labor is light は. In Comparative Example 3, the coating layer was not applied, and therefore, “-” is considered out of the evaluation target.

As a result, in each of Inventive Example 1, Inventive Example 3, Inventive Example 4 and Inventive Example 6, the ease of manufacturing was ○, but in Comparative Example 13, two layers were not coated. In addition, the ease of manufacture was Δ.

From the above, it can be seen that all of the invention examples 1, 3, 4 and 6 have a comprehensive evaluation of 以上 or more and a easiness of production ○ in the water pan discoloration test.

From the above experimental results, although the difference in the durability to prevent discoloration can not be confirmed depending on the presence or absence of aluminum only with the metal layer 11, aluminum is contained as the metal layer 11, and a silicon compound is further formed on the upper layer of the metal layer 11, The example of the present invention in which the coating layer 12 formed of a single layer containing any of an aluminum compound and a zirconium compound is formed is compared with the case where the above-mentioned coating layer 12 is formed on the upper layer of the metal layer 11 without aluminum. It was found that the color change resistance durability was significantly improved.

Furthermore, when this coating layer 12 was a single layer containing a silicon compound, it turned out that discoloration prevention durability exceeding the comparative example which laminated | stacked the two-layer film | membrane by the metal layer which does not contain aluminum can be exhibited by a single layer.

In addition, the effect of the aluminum-containing base material is similarly shown in Comparative Example 13, and the durability can be further improved, but the material cost becomes excessive by laminating over two layers, and the number of laminating processes increases. It has been found that there is a point inferior to the inventive example in terms of an increase in production labor and long production time.

Second Embodiment The second embodiment of the surface-treated metal member to which the present invention is applied will be described in detail with reference to the drawings.

The surface-treated metal member according to the second embodiment is used, for example, for Gotoku 3 or the like as a heating appliance with which a direct fire is in contact during cooking as shown in FIG. 1A. Five virtues 3 are used for gas stove 2 in a system kitchen. There are many cases where Gotoku 3 is shaped like a nail that extends from the periphery of the gas stove 2 toward the center, and a heating container such as a kettle or a pan is placed. Gotoku 3 is often used in high temperature environments of 700 ° C or more because it is located in the vicinity of the open flame emitted from gas stoves, and is used in high temperature environments of 1000 ° C or more when exposed to direct fire Often

Incidentally, as an example of the stainless steel constituting the metal layer 11, stainless steel or the like containing at least aluminum may be used. At this time, the content of aluminum with respect to the total weight of the stainless steel is not particularly limited, but it is desirable to be, for example, 4% by weight.

The coating layer 12 has a first layer 21 laminated on the surface of the metal layer 11 as shown in FIG. 4 and a second layer 22 laminated on the first layer 21 to form the outermost surface. ing.

The first layer 21 is composed of a layer containing a silicon compound. The silicon compound constituting the first layer 21 is a concept that includes all the compounds containing Si. The silicon compound may also be embodied as a silicic acid compound. This silicic acid compound is a concept including all if it is a compound having a bond of Si and O, and examples thereof include dehydrated and condensed silicon tetraethoxide, SiO ₂ , polysilazane, siloxane, silicate and the like. is there. However, this silicon compound is not limited to these examples. The first layer 21 is made of a material exhibiting transparency, so that the metal color of the metal layer 11 covered by itself can be positively shown on the surface. However, it goes without saying that the first layer 21 may be made of materials other than the material exhibiting transparency.

The first layer 21 can suppress the movement of mainly the Fe element in the metal layer 11 from diffusing into the second layer 22. That is, the first layer 21 can act as a barrier to the movement of the Fe element, and in turn, the Fe element can be prevented from reaching the second layer 22. As a result, it is possible to prevent the Fe element from being oxidized in a high temperature environment of 700 ° C. or higher, and more than 1000 ° C. And it can prevent that a black spot arises by oxidizing this Fe element.

It is desirable that the coating amount of the first layer 21 is more than 300 mg / m ^{2 and} less than 3000 mg / m ^{2 in} total of converted values of SiO ₂ . However, the first layer 21 is not limited to the case where it is configured by such a coating amount, and it may be any coating amount.

If the coating amount of the first layer 21 is 300 mg / m ² or less, the film thickness is too thin, so that an interference color occurs and a stable appearance can not be maintained. In addition, when it comes in contact with a flame that reaches temperatures as high as 1200 ° C., it discolors and a black point is generated. On the other hand, when the coating amount of the first layer 21 is stacked over 3000 mg / m ² , the film thickness of the first layer 21 as the barrier layer is too thick, and the metal layer 11 is The contained gas can not be removed, and this appears as a white turbid pattern, which causes the appearance and the design to be degraded.

In the silicon compound of the first layer 21, the paint as the precursor thereof may be a crystal particle dispersion liquid, or may be obtained from a non-crystalline paint. When the paint that is the precursor of the silicon compound is a crystal particle dispersion, the Fe element in the metal layer 11 has to move so as to bypass this crystal, so this barrier layer The amount of movement when passing through the first layer 21 is increased, and thus the diffusion of the Fe element to the second layer 22 can be prevented. However, even if the silicon compound of the first layer 21 is obtained from a non-crystalline paint, it is of course possible to act to suppress the diffusion of the Fe element.

Another layer may be interposed between the first layer 21 and the metal layer 11.

The second layer 22 is composed of a layer containing an aluminum compound. Examples of the aluminum compound constituting the second layer 22 include Al ₂ O ₃ , (aluminum nitride, mullite, spinel) and the like. Desirably, crystalline Al ₂ O ₃ may be used as this aluminum compound. However, this aluminum compound is not limited to these examples. The second layer 22 is made of a material exhibiting transparency, so that the metallic color of the metal layer 11 covered by itself can be positively shown on the surface. However, it goes without saying that the second layer 22 may be made of materials other than the material exhibiting transparency.

The aluminum compound constituting the second layer 22 does not cause crystal transition or the like in a high temperature range of 700 ° C. or higher, and more than 1000 ° C., and appearance defects hardly occur in such a high temperature range. That is, the appearance of the second layer 22 hardly occurs in the high temperature environment due to being located near the open flame. In addition to this, in the second layer 22, the first layer 21 functions as a barrier layer for diffusion of Fe element, so that it can be prevented from being diffused inside. For this reason, it becomes a structure which the oxidation itself by oxidation of Fe can not occur in an aluminum compound, and it can prevent that a temper color generate | occur | produces by what is called oxidation discoloration.

It is desirable that the coating amount of the second layer 22 is more than 100 mg / m ^{2 and} less than 2500 mg / m ^{2 in} total of Al ₂ O ₃ converted values, particularly in the case of an aluminum compound. However, the second layer 22 is not limited to the case where it is configured by such a coating amount, and may be any coating amount.

If the coating amount of the second layer 22 is stacked over 2500 mg / m ² , the film thickness becomes too thick, and under the high temperature environment described above, the line between the metal layer 11 and the second layer 22 Due to the difference in expansion coefficient, the second layer 22 may be peeled off and coating film cracking may occur.

In such a case, the second layer 22 can suppress appearance defects due to the high temperature environment exceeding 700 ° C. through the aluminum compound. In addition, although the Fe element in the metal layer 11 tries to diffuse under this high temperature environment, the diffusion toward the first layer 21 is suppressed through the silicon compound constituting this. As a result, it is possible to suppress the movement of the diffused Fe element passing through the first layer 21 and entering the second layer 22. As a result, since the Fe element does not enter the second layer 22, it can be prevented from being oxidized in a high temperature environment, and the color change can be prevented. In particular, when aluminum is contained in the stainless steel constituting the metal layer 11, stainless steel not containing aluminum is provided with the first layer and the second layer of the present invention, or heat resistant stainless steel containing aluminum. When exposed to a high temperature environment over 700 ° C. for a long time, the time until the naked eye could detect the discoloration due to oxidation was significantly longer than that without the coating. In this way, an effect of significantly improving the durability of preventing discoloration due to oxidation is produced.

The present invention is not limited to the case where it is applied to heating appliances such as Gotoku 3 or grille, and any metal member used in a high temperature environment may be applied. It is also good. For example, it goes without saying that the present invention may be applied to a gas burner 5 as shown in FIG. 3, heater parts, boiler piping and the like. Even in the gas burner shown in FIG. 3, the first layer 21 is formed on the upper layer of the metal layer 11 constituting the metal member constituting the surface, and the second layer 22 is formed on the upper layer thereof. And this metal layer 11 is comprised with the stainless steel material containing aluminum.

Further, the present invention is not limited to these, and may be applied to any device having a metal member heated to a high temperature. In such a case, the first layer 21 is formed on the upper layer of the metal member made of stainless steel containing aluminum, and the second layer 22 is formed on the upper layer thereof.

In this experimental verification, first, as shown in Table 2, a plurality of samples are prepared, and five items of appearance after coating, coating film cracking, degree of corrosion, degree of whitening, presence or absence of water pan discoloration test are verified The

The sample is constituted only by the metal layer 11, and the first and

second layers

21 and 22 are formed on the metal layer 11 in Comparative Examples 1 and 2 in which the first layer 21 and the second layer 22 are not laminated on the surface. It consists of Comparative Example 3 of the present invention, which is stacked over two layers.

Among them, Comparative Example 1 and Comparative Example 3 use stainless steel (19Cr-0.4Cu-0.4Nb-LC, N) containing no aluminum as the metal layer 11, and Comparative Example 2 and the invention example Uses a stainless steel (15Cr-4Al-LC, N) containing 4% by weight of aluminum based on the total weight of the stainless steel as the metal layer 11.

The first layer 21 applied in the experiment is a crystal dispersion mainly composed of silica having a concentration of 10% and an average diameter of 25 nm or more.

The second layer 22 applied in the experiment is a dispersion of aluminum hydroxide nanoparticles having a concentration of 3% and an average diameter of 200 nm or more.

The experimental verification conducted to confirm the effect of the surface-treated metal member to which the present invention is applied will be described in detail.

Regarding the evaluation method of each item, first, the appearance after painting is evaluated by visual observation according to JIS K5600-4-3 (only light source uses LED (Ohm Electric LED PL 48 W) after painting and baking, and appearance abnormality is If there is no, it is ○, and if an appearance abnormality is found, it is ×. The appearance evaluation after this painting is that the floor surface wall is all neutral gray (SCI value is 47.69) and the illuminance at the observation position is about 1100 Lux and the floor surface wall is all white (SCI value is 90.61) It was performed in both of the environments where the illuminance at the observation position is about 2300 Lux in the room.

With respect to coating film cracking, after coating baking, magnification observation is performed at 450 times with a microscope, and when there is no coating film cracking, it is marked with 、, and when coating film cracking is found, it is marked with x.

For the degree of corrosion, two cycles of JIS K 5621 7.12 combined cycle resistance test were conducted, and cases where corrosion occurred were marked as x when no corrosion occurred.

In addition, whitening is visually observed according to JIS K 5600-4-3 (only light source uses LED (Ohm Electric LED PL 48 W)) for each sample after heating by direct fire, and if whitening occurs, x If it does not occur, it is marked as ○. In this visual observation, all floor surfaces were in a room of neutral gray (SCI value of 47.69), and the illuminance at the observation position was about 1100 Lux.

For the water pan discoloration test, place a pan (diameter 24 cm) containing 2 l of water in the heater provided with Gotoku on which the coatings of Comparative Examples 1 to 3 and the inventive example of Embodiment 2 were applied. The heating was repeated continuously for 1 hour using the high-calorie burner, and the color change was visually evaluated according to JIS K5600-4-3 (using only the light source LED (Ohm Electric LED PL 48 W)). About this water pan discoloration test, the floor surface wall was all white in a room (SCI value 90.61), and the illumination intensity of the observation position was about 2300 Lux.

In the water pan discoloration test, as a result of visual evaluation under the above-mentioned conditions, ○ is obtained when there is no discoloration, Δ when there is little discoloration, and x when the discoloration is large.

In addition, about the amount of adhesion, the quantitative analysis by a fluorescent-X-ray-analysis apparatus is performed. As a device, a wavelength dispersion tabletop fluorescent X-ray analyzer (Supermini 200) manufactured by Rigaku Corporation was used.

The appearance after coating, the coating film cracking, and the whitening test of Comparative Examples 1 and 2 are not included in the evaluation because there is no coating film itself. In the corrosion test, Comparative Example 1 was x and Comparative Example 2 was x.

On the other hand, in Comparative Example 3 and the invention example, the appearance after coating and the coating film cracking were both ○, and both of the corrosion test and the whitening test were ○.

Table 3 has shown the evaluation result according to the elapsed time from the heating start of a water pan discoloration test.

In the water pan discoloration test results, Comparative Examples 1 and 2 became △ at 2 minutes after the start of heating. Further, in the water pot discoloration test results, Comparative Example 3 became △ after 310 hours of heating, but Example of the invention became △ after 1700 hours from the start of heating.

From the above experimental results, in the present invention example in which aluminum is contained as the metal layer 11 and the first layer 21 and the second layer 22 are formed on the upper layer of the metal layer 11, the metal layer 11 does not contain aluminum. The anti-discoloring durability improvement effect was 5.5 times as excellent as when laminated. In addition, the conditions about the water pan discoloration test shown by the experimental verification in this Table 3 quote the description about Table 1 mentioned above. The details of each item in the table are also the same as in Table 1.

2 Gas Stove 3 Gotoku 5 Gas Burner 11 Metal Layer 12 Coating Layer 21 First Layer 22 Second Layer

Claims

In a surface-treated metal member having a coating layer formed on the surface of the metal layer,
The metal layer is a stainless steel material containing aluminum,
The surface-treated metal member, wherein the coating layer is composed of a single layer containing any of a silicon compound, an aluminum compound, and a zirconium compound.
The surface treatment according to claim 1, wherein the coating layer is a single layer containing any of a silicate compound as the silicon compound, an aluminum oxide compound as the aluminum compound, and a zirconium oxide compound as the zirconium compound. Metal members.
In a surface-treated metal member having a coating layer formed on the surface of the metal layer,
The metal layer is a stainless steel material containing aluminum,
A surface-treated metal member, comprising: a first layer containing a silicon compound; and a second layer laminated on the first layer, the second layer containing an aluminum compound.
The first layer contains a silicate compound as the silicon compound,
The surface-treated metal member according to claim 3, wherein the second layer contains an aluminum oxide compound as the aluminum compound.
The surface-treated metal member according to claim 4, wherein the paint as a precursor of the first layer is a crystal particle dispersion liquid.
The surface-treated metal member according to any one of claims 1 to 5, wherein the coating layer exhibits transparency.
Having a metal member to be heated,
A heating apparatus characterized in that the surface-treated metal member according to any one of claims 1 to 6 is used for the metal member.