JP6978841B2 - Surface-treated metal parts for cooking utensils, cooking utensils - Google Patents

Description

The present invention, gas stove, grill, trivet, lighters, Oite the metal member to be used in open flame touches instrument at the time of heating as cooker tool such as a pan, by preventing oxidation of the metal due to the high temperature, surface-treated metal member for cookware capable of effectively preventing the discoloration over time, and to a cooking appliance which is used.

Stainless steel has an extremely thin and highly protective passivation film with a thickness of several nm to several ten nm, and exhibits excellent corrosion resistance and heat resistance while maintaining a beautiful metallic luster. For this reason, conventionally, heating appliances such as gas stoves, grills, trivets, gas burners, etc. that are exposed to direct fire during heating, and equipment used in high temperature environments such as heater parts, drying and baking furnaces, boiler piping, etc. are configured. It is used as a material for grilling.

However, in the above-mentioned high temperature environment, the surface of this stainless steel may be discolored and colored, so-called temper color may occur. Such discoloration of stainless steel is based on the fact that the stainless steel is oxidized by high temperature to form an oxide layer. When the thickness of this 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 the impression that the appearance and design are sharply deteriorated. In particular, heating appliances such as trivets, gas stoves, and gas burners may show such discoloration just by touching an open flame, even though it has not been so many days since they were purchased. It gives the impression that it is suddenly out of date.

Therefore, a technique capable of preventing discoloration due to oxidation of stainless steel in a high temperature environment has been conventionally studied. First, Patent Document 1 discloses a technique in which a reaction layer having a thickness of 5 to 100 nm is interposed between a steel substrate and an alkaline silicate film in a stainless steel material having an alkaline silicate film on the surface. Through this reaction layer, it is expected that the diffusion of atoms to the alkaline silicate film covering the surface of the steel material will be suppressed, the formation of the Cr-Fe-O oxide layer that causes the generation of temper color will be stopped, and discoloration will be prevented. It was done.

Further, Patent Document 2 discloses a technique for forming a silicic acid compound film made of polysilazane on the surface of stainless steel. Since this silicic acid compound is an oxide in which oxygen diffusion is slow, it is expected that discoloration will be prevented by suppressing the progress of oxidation occurring in the vicinity of the surface of stainless steel.

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

Further, Patent Document 4 discloses a technical idea of using an alumina thin film as an oxidation-suppressing film. The alumina thin film has excellent film forming properties, compactness, thermal stability, electrical insulation, etc., 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 Document 1-4, although it is possible to prevent discoloration due to oxidation of stainless steel at high temperature, the base material is gradually oxidized by long-term high temperature use, and particularly at 700 ° C. There was a problem that the durability against the temper color was insufficient in the ultra-high temperature range exceeding the above.

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

Japanese Unexamined Patent Publication No. 2008-231551 JP-A-2015-44300 Japanese Unexamined Patent Publication No. 2004-292877 Japanese Unexamined Patent Publication No. 2013-216760 Japanese Unexamined Patent Publication No. 2002-339048 Japanese Patent Publication No. 2005-504176

Therefore, the present invention has been devised in view of the above-mentioned problems, and an object thereof is a surface-treated metal member capable of preventing discoloration due to oxidation in a high temperature environment for a long period of time , particularly. It is an object of the present invention to provide a surface-treated metal member for a cooking utensil , as well as a heating utensil in which it is used , particularly a cooking utensil. That is, an object of the present invention is to improve the durability of temper color suppression by the coating film.

In order to solve the above-mentioned problems, the present inventors are surface-treated metal members for cooking utensils in which a single coating layer is formed on the surface of a stainless steel material on which a passivation film containing aluminum is formed. The coating layer contains either a silicon compound or a zirconium compound, and the coating layer exhibits transparency, and the surface-treated metal member for cooking utensils has a structure in which the metallic color of the metal layer is exhibited on the surface. , As well as the cookware in which it is used.

Surface-treated metal member for cookware according to the first invention, the surface-treated metal member for cookware coating layer formed on the surface of the metal layer passive film is formed, the metal layer is aluminum It is a stainless steel material containing, and the coating layer is composed of a single layer containing either a silicon compound or a zirconium compound, and the coating layer exhibits transparency and exhibits the metallic color of the metal layer on the surface. It is characterized by being.

In the first invention, the surface-treated metal member for a cooking utensil according to the second invention is composed of a single layer containing either a silicic acid compound as the silicon compound and a zirconium oxide compound as the zirconium compound. It is characterized by that.

The cooking utensil according to the third invention has a metal member to be heated, and the surface-treated metal member for the cooking utensil of the first invention or the third invention is used for the metal member.

According to the present invention having the structure described above, the silicon compound constituting the coating layer, it is possible to suppress the oxidation of the substrate by the gas barrier properties of the di Rukoniumu compound. Further, according to the present invention, by containing aluminum in the stainless steel constituting the metal layer, discoloration due to oxidation can be detected with the naked eye when the stainless steel containing no aluminum is exposed to a high temperature environment for a long time. It is possible to prolong the time until so-called durability can be improved. This improvement in durability has a remarkable effect that cannot be inferred from the difference in oxidative discoloration prevention durability between the base materials.

Further, according to the present invention, since the metallic luster state can be maintained for a long period of time, it is possible to provide a cooking utensil having excellent design.

It is a figure which shows the heating appliance to which the surface-treated metal member to which this invention is applied is applied. It is a figure for demonstrating each layer constituting the surface-treated metal member to which this invention is applied. It is a figure which shows the example which formed the coating layer on the upper layer of the metal member which constitutes the surface of a gas burner.

Hereinafter, 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 to which the present invention is applied is used, for example, in Gotoku 3 or the like as a heating appliance that is exposed to an open flame during cooking as shown in FIG. 1 (a). The trivet 3 is used for the gas stove 2 in the system kitchen. The trivet 3 is often configured in the shape of a claw extending from the periphery of the gas stove 2 toward the center, and a heating container such as a kettle or a pot is placed therein. Since Gotoku 3 is located near an open flame that ignites from a gas stove, it is often used in a high temperature environment of 700 ° C or higher, and when it comes into contact with an open flame, it is used in a high temperature environment of 1000 ° C or higher. In many cases.

FIG. 1 (b) shows a cross-sectional view taken along the line BB'in the surface-treated metal member constituting the trivet 3. The surface-treated metal member constituting the trivet 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 a metal such as stainless steel. It is essential that the metal layer 11 contains aluminum among the stainless steels. In stainless steel, the added Cr combines with oxygen in the air to form an extremely thin and highly protective passivation film having a thickness of several nm to several ten nm. This passivation film exhibits excellent corrosion resistance and heat resistance. That is, the trivet 3 can prevent the generation of rust by the metal layer 11 on which the passivation film is formed.

Incidentally, as an example of the stainless steel constituting the metal layer 11, at least stainless steel containing aluminum or the like 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 composed of a layer containing a silicon compound, an example of the silicon compound is a concept including all compounds having Si, for example, dehydration-condensed silicon tetraethoxy. Do, polysilazane, siloxane, silicate, silicon nitride, silicon carbide, etc. However, this silicon compound is not limited to these examples.

When the coating layer 12 is composed of a layer containing an aluminum compound, examples of the aluminum compound are Al ₂ O ₃ , aluminum nitride, mullite, spinel and the like. However, this aluminum-based compound is not limited to these examples.

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

Since the coating layer 12 is made of a transparent material, it is possible to positively show the metallic color of the metal layer 11 that it covers on the surface. However, it goes without saying that the coating layer 12 may be made of a material other than the material exhibiting transparency.

The silicon compound, aluminum compound, and zirconium compound constituting the coating layer 12 function as a barrier layer that suppresses the oxidation of the metal substrate by oxygen in the air, so that a temper color due to so-called oxidative discoloration is generated. It can be prevented from being stored.

The operation of the trivet 3 having the surface-treated metal member having the above-mentioned structure will be described below. When the cooking container placed on the trivet 3 is heated by the direct fire by the gas stove 2, the trivet 3 is located in the vicinity of the direct fire, and in some cases, the direct fire comes into direct contact with the cooking container. As a result, the trivet 3 will be placed in a high temperature environment exceeding 1000 ° C. Even if it does not come into direct contact with an open flame, it will be exposed to a high temperature environment of 700 ° C. or higher in the vicinity of the open flame.

In such a case, the coating layer 12 can prevent oxidation in a high temperature environment by suppressing the oxygen in the air from reaching the metal substrate via the silicon compound, the aluminum compound, and the zirconium compound. It is possible to prevent discoloration. Further, since the stainless steel constituting the metal layer 11 contains aluminum, the stainless steel containing no aluminum is coated with the coating layer 12 of the present invention, and the heat-resistant stainless steel containing aluminum is not coated. When exposed to a high temperature environment exceeding 700 ° C. for a long time, it took a significantly longer time to detect discoloration due to oxidation with the naked eye. In this way, the effect of significantly improving the durability of preventing discoloration due to oxidation is produced.

It should be noted that the present invention is applied to an object that is not directly exposed to fire but is required to be durable at high temperatures, except when applied to an instrument such as the trivet 3 that is directly exposed to fire. The present invention is not limited to the case where it is applied to a heating appliance such as a gas stove, a grill, a lighter, a pan, etc. other than the trivet 3, and is applied to any metal member used in a high temperature environment. It may be what is done. For example, it goes without saying that the present invention may be applied to a gas burner 5, a heater component, a stove, an exhaust pipe, a boiler pipe, or the like as shown in FIG. 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 thereof. The metal layer 11 is made of a stainless steel material containing aluminum.

Further, according to the present invention, even if the coating layer 12 composed of any one of a silicon compound, an aluminum compound, and a zirconium compound is composed of a single layer, by coating the stainless steel material containing aluminum, the effect of preventing discoloration due to oxidation can be obtained. Can be expressed. Therefore, if the purpose is to improve the durability of preventing discoloration due to oxidation, especially in a place not directly exposed to fire, the material cost is reduced as compared with the case where the coating layer 12 is composed of two or more layers. By reducing the number of laminating processes, it is possible to reduce the manufacturing labor and, by extension, 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 the stainless steel material containing aluminum.

Hereinafter, the 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 the experimental verification in Example 1, first, as shown in Table 1, a plurality of types of samples were prepared and a water pot discoloration test was performed.

The sample is 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 thereof, and the coating layer 12 containing the above-mentioned components on the metal layer 11 containing no aluminum as a single layer. Comparative Examples 5 to 11 laminated over a single layer, Examples 1 to 7 of the present invention in which a coating layer 12 containing the above-mentioned component was laminated over a single layer on a metal layer 11 containing aluminum, and the above-mentioned above on the metal layer 11. It is composed of Comparative Examples 12 and 13 in which the coating layer 12 containing the above-mentioned components is laminated over two layers.

For Comparative Examples 1, 2 and 5 to 12, stainless steel containing no aluminum (SUS304) and stainless steel containing no aluminum (SUS430) were used as the metal layer 11, and Examples 1 to 7 of the present invention and Comparative Example 2 were used. For 3 and 13, the metal layer 11 is a stainless steel (15Cr-4Al-LC, N) containing 4% by weight of aluminum with respect to the total weight of the stainless steel, and the metal layer 11 is 2 weight with respect to the total weight of the stainless steel. Stainless steel (18Cr-2Al-Ti) containing% aluminum is used.

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

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

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

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

In Comparative Examples 12 and 13, the above-mentioned silicon compound main film A is laminated directly on the metal layer, and the above-mentioned aluminum compound main film is laminated directly on the silicon compound main film A to form a two-layer structure.

Each of the above-mentioned samples was experimentally verified by a water pot discoloration test. For the water pot discoloration test, 2 liters of water was placed in a pot (diameter 24 cm) having a metal layer 11 made of stainless steel and repeatedly heated with a 4.4 kW high calorie burner for 1 hour, and JIS K 5600-4. Discoloration was visually evaluated according to -3 (only the light source uses LED (Ohm Electric LEDPL48W)). This water pot discoloration test was conducted in a room where the floor wall surface was all white (SCI value was 90.61), and the illuminance at the observation position was about 2300 Lux.

In Table 1, SUS304 is taken as a representative of the metal containing no aluminum in the metal layer 11, and stainless steel (15Cr-4Al-LC, N) containing 4% by weight of aluminum is taken as a representative of the metal containing aluminum. The effect of improving the durability against discoloration of the aluminum-containing metal is shown by the magnification. This discoloration prevention durability improvement effect is
Discoloration prevention durability improving effect = (discoloration start time (h) in a stainless steel specimen containing 4% by weight of aluminum) / (discoloration start time (h) in a SUS304 sample)
It is represented by. This discoloration prevention durability improvement effect is confirmed more than 3 times, and the discoloration prevention durability is more than 310h ◎, the effect of the aluminum-containing base material is confirmed more than 3 times, but the discoloration prevention durability is less than 310h. A total evaluation was performed with ◯ and × for those for which the effect of the aluminum-containing base material was not confirmed.

In the water pot discoloration test, visual evaluation was performed under the above-mentioned conditions. First, as Comparative Examples 1 to 4, a water pan discoloration test was performed on SUS304 and SUS430 containing no aluminum, stainless steel containing 4% by weight of aluminum, and stainless steel containing 2% by weight of aluminum without coating. The discoloration start time was measured.
As a result, the discoloration start time was 2 minutes regardless of the substrate. From this, the effect of improving the discoloration prevention durability of the aluminum-containing substrate was not confirmed without any coating, and the overall evaluation was x.

Next, as Comparative Examples 5 to 7, SUS304 and SUS430 containing no aluminum, and Examples 1 to 3 of the present invention include stainless steel containing 4% by weight of aluminum and stainless steel containing 2% by weight of aluminum. Under the above coating conditions, the silicon compound main film A and the silicon compound main film B were coated, and a water pot discoloration test was conducted for each of them, and the discoloration start time was measured. As a result, the discoloration start time of Comparative Examples 5 to 7 was 110 hours, but the discoloration of all of Examples 1 to 3 of the present invention was not confirmed even at 470 hours.

From this, by laminating the coating layer 12 containing the silicon compound on the metal layer 11 containing aluminum, the effect of improving the discoloration prevention durability is at least as compared with the case where the coating layer 12 containing the silicon compound is laminated on the metal layer 11 containing no aluminum. It was found that the durability was four times or more, and the durability of the two-layer film having the best anti-discoloration durability in the metal layer 11 containing no aluminum exceeded 310 hours in Comparative Example 12, so the overall evaluation was ⊚. ..

Next, with respect to SUS304 and SUS430 containing no aluminum as Comparative Examples 8 and 9, stainless steel containing 4% by weight of aluminum as Examples 4 and 5 of the present invention and stainless steel containing 2% by weight of aluminum of the present invention. The aluminum compound main film was coated under the coating conditions, and a water pot discoloration test was conducted for each of them, and the discoloration start time was measured.

As a result, in Comparative Examples 8 and 9, the discoloration start time was 10 hours and 4 hours, respectively, but in the present 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 with the case where the coating layer 12 containing the aluminum compound is laminated on the metal layer 11 containing no aluminum. It was found that the value was 14.5 times or more, and the effect of the aluminum-containing base material was confirmed, but the durability did not exceed 310 hours, so the overall evaluation was ◯.

Next, as Comparative Examples 10 and 11, SUS304 and SUS430 containing no aluminum were used, and as Examples 6 and 7, stainless steel containing 4% by weight of aluminum and stainless steel containing 2% by weight of aluminum of the present invention were used. Under the coating conditions, the aluminum compound main film was coated, and a water pot discoloration test was conducted for each, and the discoloration start time was measured.

As a result, the discoloration start time of Comparative Examples 10 and 11 was 45 minutes, but the discoloration start time of Examples 6 and 7 of the present invention was 4 hours and 18 hours, respectively.

From this, by laminating the coating layer 12 containing the zirconium compound on the metal layer 11 containing aluminum, the effect of improving the discoloration prevention durability is improved as compared with the case where the coating layer 12 is laminated on the metal layer 11 containing no aluminum. It was found that the value was 5 times higher, and the effect of the aluminum-containing base material was confirmed, but the durability did not exceed 310 hours, so the overall evaluation was ◯.

Next, as Comparative Examples 12 and 13, SUS304 containing no aluminum and stainless steel containing 4% by weight of aluminum were laminated with the above-mentioned silicon compound A directly above the metal layer under the coating conditions of the example of the present invention, and the silicon was laminated. The above-mentioned aluminum compound main film was laminated directly on the compound A, and a water pan discoloration test was performed on each of them, and the discoloration start time was measured.

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

Therefore, by laminating the coating layer 12 having a two-layer structure of the coating layer containing the silicon compound and the coating layer containing the aluminum compound on the metal layer 11 containing aluminum, the metal layer 11 containing no aluminum is laminated. It was found that the effect of improving the discoloration prevention durability was 5.5 times that of the case of laminating in aluminum, and the durability also exceeded 310 hours, so the overall evaluation was ⊚.

In addition, in this example, the ease of manufacture was also evaluated. For ease of manufacture, the present invention example 1, the present invention example 3, the present invention example 4, and the present invention example 6 are obtained by laminating a coating layer on a metal layer 11 (15Cr-4Al-LC, N) containing aluminum, respectively. Comparative Example 13 was evaluated. The evaluation index for ease of manufacture measures the time required to coat the coating layer, and also asks the operator to evaluate the actual burden of coating labor in three stages. The manufacturing time is long and the burden of manufacturing labor is burdened. When is large, it is marked with x, when the manufacturing time is medium, the burden of manufacturing labor is medium, it is marked with Δ, and when the manufacturing time is short and the burden of manufacturing labor is light, it is marked with ○. In Comparative Example 3, since the coating layer is not applied, it is not evaluated, so it is set as “−”.

As a result, the ease of manufacture was ◯ in all of the present invention example 1, the present invention example 3, the present invention example 4, and the present invention example 6, whereas in the comparative example 13, two layers had to be coated. However, the ease of manufacture was Δ.

From the above, it can be seen that the cases in which the comprehensive evaluation of the water pot discoloration test is ◯ or higher and the manufacturability is ◯ are all the examples 1, 3, 4, and 6 of the present invention.

From the above experimental results, it is not possible to confirm the difference in the durability of discoloration prevention depending on the presence or absence of aluminum in the metal layer 11 alone. The example of the present invention in which the coating layer 12 made of a single layer containing either an aluminum compound or a zirconium compound is formed is compared with the case where the above-mentioned coating layer 12 is formed on an upper layer of a metal layer 11 that does not contain aluminum. It was found that the discoloration prevention durability was significantly improved.

Further, it was found that when the coating layer 12 is a single layer containing a silicon compound, the single layer can exhibit discoloration prevention durability exceeding the comparative example in which a two-layer film is laminated with a metal layer containing no aluminum.

Further, Comparative Example 13 also shows the effect of the aluminum-containing base material, and it is possible to further improve the durability, but the material cost becomes excessive by laminating over two layers, and the laminating process increases. It was found that there is a point inferior to the example of the present invention from the viewpoint of increasing the manufacturing labor and prolonging the manufacturing time.

2 Gas stove 3 Gotoku 5 Gas burner 11 Metal layer 12 Coating layer

Claims (3)

In a surface-treated metal member for cooking utensils in which a coating layer is formed on the surface of a metal layer in which a passivation film is formed,
The metal layer is a stainless steel material containing aluminum.
The coating layer is composed of a single layer containing either a silicon compound or a zirconium compound, and is also composed of a single layer .
The coating layer is a surface-treated metal member for cooking utensils , which exhibits transparency and has a structure in which the metallic color of the metal layer is represented on the surface thereof. The surface-treated metal member for a cooking utensil according to claim 1, wherein the coating layer comprises a single layer containing any one of a silicic acid compound as the silicon compound and a zirconium oxide compound as the zirconium compound. Has a metal member to be heated,
Cookware surface-treated metal member for cookware according to claim 1 or 2 wherein wherein is characterized in that it is used for the metal member.

Images