KR101683077B1 - Ceramic coating methods of iron-based substrate introduced Si oxide layer for corrosion resistance - Google Patents

Abstract

The present invention relates to a ceramic coating method of an iron-based substrate having an Si oxide layer with corrosion resistance and, more specifically, to a ceramic coating method of an iron-based substrate having an Si oxide layer with corrosion resistance, which prevents cracks, corrosion, and separation and has heat resistance, abrasion resistance, discoloration resistance, and non-adhesion by treating the surface of an iron-based substrate having Si with heat to form a ceramic layer and forming a ceramic coating layer thereon.

Description

TECHNICAL FIELD [0001] The present invention relates to a ceramic coating method of an iron-based substrate into which a corrosion-resistant Si oxide layer is introduced,

TECHNICAL FIELD The present invention relates to a ceramic coating method of a ferrous base material into which a corrosion-resistant Si oxide layer is introduced. More specifically, the present invention relates to a method of coating a ferrous base material containing Si on a surface of a ferrous base material by introducing a ceramic layer by a special heat treatment and forming a ceramic coating layer thereon And a ceramic coating method of an iron base material into which a corrosion-resistant Si oxide layer having effects such as heat resistance, abrasion resistance, corrosion resistance, discoloration resistance and non-tackiness is introduced.

Although ceramic coatings have the advantages of high hardness and environmental friendliness, there is a problem that the metal materials that can be applied due to the porous structure, which is a characteristic feature of the ceramic coating, are limited. In the case of metals such as aluminum or titanium, it is possible to apply a ceramic coating without cracking or corrosion because it forms a dense oxide film on the surface, but applying a ceramic coating to a corrosion-sensitive material such as an iron material is a problem. That is, since the porous structure of the ceramic coating layer provides a passage through which corrosive substances (oxygen ions, chlorine ions, etc.) can easily pass, when the ceramic coating is applied to the steel material, corrosion occurs, Resulting in problems such as deterioration and peeling of the coating layer. The corrosive substance introduced through the pores reacts with the steel material to form iron oxide, which expands more than three times in volume, and generates tensile stress in the ceramic coating layer to crack or peel off the ceramic coating layer.

Currently widely used ceramic coating technologies are for thin film coatings and are widely used in kitchen appliances, semiconductors, displays, etc., and there are processes for abrasion and corrosion resistance such as CVD (chemical vapor deposition) and PVD (physical vapor deposition) . However, since the coating layer formed by the thin film coating process such as CVD and PVD has cracks or peeling phenomenon when the thickness is several micrometers or more, it is not suitable for the process requiring more than a certain thickness for corrosion resistance. On the other hand, the spraying process, which is widely used for the corrosion-resistant coating, can coat a thickness of several hundred micrometers or more at high speed, but has defects such as pores and cracks in the coating layer and has difficulty in thickness control and surface roughness.

Among ceramic coating applications, heating cookers use aluminum or stainless steel, which are expensive materials instead of low-cost materials. Generally, the steel material is used as a main raw material in the modern industry because of its strength, workability, low price and ability to be reused. However, the main reason why the steel cooking material can not be manufactured using the steel material is that when the steel material is left in the air This is due to the corrosiveness, which is oxidized more severely when the heat is applied, particularly in the case of a heating cooker, and rust is generated.

As a result, surface treatments have been introduced to compensate for such defects in steel materials. One of the most widely used surface treatment methods for steel materials is the physical treatment of steel surfaces using PVD process, A process for improving chemical properties such as rust resistance, corrosion resistance and high-temperature oxidation resistance, and at the same time, increasing abrasion resistance has been carried out.

Korean Patent Laid-Open No. 10-0869711 (the name of the invention: a surface treatment method for surface modification of a kitchen cooking apparatus, hereinafter referred to as "prior art 1") is a surface treatment method of an aluminum cooking utensil, , A sealing process, a sandblasting process, a coating process and a drying process.

The above prior art 1 discloses a hard processing, a sealing process, a sandblasting process, a coating process, and a drying process as a surface treatment method of an aluminum cooking utensil, but aluminum materials having complicated processing steps and high prices are used There is a problem that the manufacturing cost is increased, and the method disclosed in the prior art has a limitation in preventing cracking and corrosion of the coating layer and increasing the coating efficiency.

It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not intended to limit the invention to the precise form disclosed. There will be.

In order to accomplish the above object, the present invention provides a method for manufacturing a semiconductor device, which comprises the steps of introducing a ceramic layer by performing a specific heat treatment on the surface of an iron-based substrate containing Si and forming a ceramic coating layer thereon to prevent cracking, corrosion and peeling, Based substrate having a corrosion-resistant Si oxide layer having effects such as resistance to discoloration and non-tackiness, and the like.

In the embodiment of the present invention, a ceramic coating method of a ferrous base material into which a corrosion-resistant Si oxide layer is introduced includes the steps of (i) preparing an iron base material containing Si by pretreatment, (ii) heat treating the surface of the pre- (Iii) forming a ceramic coating layer on the Si oxide layer, and (iv) drying and firing the iron-based substrate having the ceramic coating layer formed thereon.

In an embodiment of the present invention, the Si oxide layer in the step (ii) may be at least one of Fe ₂ SiO ₄ and SiO ₂ .

In an embodiment of the present invention, the thickness of the Si oxide layer in the step (ii) may be 0.1 to 5 占 퐉.

In the embodiment of the present invention, the thermal expansion coefficient of the Si oxide layer in the step (ii) is 0.3 to 3 ppm / K, and the thermal expansion coefficient of the ceramic coating layer may be lower than the thermal expansion coefficient value of the Si oxide layer.

In an embodiment of the present invention, the modulus of elasticity of the Si oxide layer may be from 60 to 80 Gpa.

In the embodiment of the present invention, the thickness of the ceramic coating layer in the step (iii) may be 30 to 60 mu m.

In the embodiment of the present invention, the critical load of the ceramic coating layer in the step (iii) may be 9N or more.

In an embodiment of the present invention, the ceramic coating layer in step (iii) may be performed with a wet spray coating.

In the embodiment of the present invention, the silicon content of the iron-base material containing Si in the step (i) may be 0.1 to 20 wt%.

In the embodiment of the present invention, the heat treatment in the step (ii) may be performed at 500 to 900 占 폚 for 20 seconds to 300 minutes.

In the embodiment of the present invention, H ₂ / H ₂ O may be performed under the condition of 0.05 to 0.6 during the heat treatment in the step (ii).

In the embodiment of the present invention, the dew point during the heat treatment in the step (ii) may be 20 to 60 ° C.

In the embodiment of the present invention, the heat treatment in the step (ii) may be performed in an oxidizing atmosphere.

According to another aspect of the present invention, there is provided a composite material for a heating and cooking apparatus, which is produced by using a ceramic coating method of a ferrous base material into which a corrosion-resistant Si oxide layer is introduced.

According to another aspect of the present invention, there is provided a heating cooker manufactured using a composite material for a heating cooker.

According to the embodiment of the present invention, the first effect of mitigating the difference in elastic modulus between the iron-based substrate surface and the ceramic layer to prevent cracking and corrosion of the ceramic coating layer can be achieved without using a separate coating agent, A ceramic coating layer having excellent effects such as heat resistance, abrasion resistance, corrosion resistance, discoloration resistance, and non-tackiness can be formed. The fourth effect that it can contribute to manufacturing cost reduction by using the iron material which is relatively cheap compared with the effect, aluminum and stainless steel material, can extend the lifetime of the product because the surface strength is excellent and the wear and scratch is not generated And has the fifth effect.

It should be understood that the effects of the present invention are not limited to the above effects and include all effects that can be deduced from the detailed description of the present invention or the configuration of the invention described in the claims.

1 is a view showing a process of a surface treatment method of an iron-based substrate for ceramic coating.

Hereinafter, the present invention will be described with reference to chemical formulas, reaction formulas, specific examples and experimental examples. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

Throughout the specification, when a part is referred to as being "connected" (connected, connected, coupled) with another part, it is not only the case where it is "directly connected" "Is included. Also, when an element is referred to as "comprising ", it means that it can include other elements, not excluding other elements unless specifically stated otherwise.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. The singular expressions include plural expressions unless the context clearly dictates otherwise. In this specification, the terms "comprises" or "having" and the like refer to the presence of stated features, integers, steps, operations, elements, components, or combinations thereof, But do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, or combinations thereof.

In the embodiment of the present invention, a ceramic coating method of a ferrous base material into which a corrosion-resistant Si oxide layer is introduced comprises the steps of (i) preparing a ferrous base material containing Si by pretreatment, (ii) heat treating the surface of the pre- (Iii) forming a ceramic coating layer on the Si oxide layer, and (iv) drying and firing the iron-based substrate having the ceramic coating layer formed thereon.

In the embodiment of the present invention, the pretreatment in the step (i) may be a washing and drying step for removing impurities from the surface of the iron-based substrate. Removal of impurities prior to formation of the oxide layer on the surface of the iron-based substrate facilitates formation of the oxide layer with high adhesion on the surface of the iron-based substrate, and the ceramic coating layer is firmly formed on the oxide layer, Can be increased.

In an embodiment of the present invention, the Si oxide layer in the step (ii) may be at least one of Fe ₂ SiO ₄ and SiO ₂ . In general, when the carbon steel is heat-treated, Fe ₂ O ₃ , Fe ₃ O ₄ and FeO oxide layers are formed on the surface with less denseness. In the case of such an oxide layer, not only an additional oxidation reaction can proceed during continuous inflow of oxygen but also the adhesion to the iron-based substrate is deteriorated and the oxide layer itself is peeled off, which causes destruction of the ceramic coating layer. However, the iron base material containing Si forms Fe ₂ SiO ₄ and SiO ₂ oxidation layer during the heat treatment, and the Fe ₂ SiO ₄ and SiO ₂ oxidation layers can be controlled according to H ₂ / H ₂ O. In general, the SiO ₂ oxide layer formed on the surface of the iron-based substrate upon heat treatment has a very dense structure and is thinly formed on the surface of the iron-based substrate and has excellent adhesion with the iron-based substrate.

In the embodiment of the present invention, the thickness of the Si oxide layer in the step (ii) may be 0.1 to 5 占 퐉. If the thickness of the Si oxide layer is less than 0.1 占 퐉, the thickness of the oxide layer is small and easily damaged, and the adhesion to the iron-based substrate is reduced, and the ceramic coating layer may be peeled and cracked even if the ceramic coating layer is formed thereon. If the thickness of the Si oxide layer exceeds 5 占 퐉, the oxide layer becomes rough and the ceramic can not be uniformly coated, and peeling and cracking may occur.

In the embodiment of the present invention, the thermal expansion coefficient of the Si oxide layer in the step (ii) is 0.3 to 3 ppm / K, and the thermal expansion coefficient of the ceramic coating layer may be lower than the thermal expansion coefficient value of the Si oxide layer. The coefficient of thermal expansion (CTE) is a numerical expression of the change in bond length between molecules or atoms as the temperature of the organic material increases. The coefficient of thermal expansion (CTE) of the ceramic coating layer is equal to or lower than the thermal expansion coefficient of the Si oxide layer The compressive stress of the ceramic coating layer is generated to prevent peeling and cracking in the process.

In an embodiment of the present invention, the modulus of elasticity of the Si oxide layer may be from 60 to 80 Gpa. When the elastic modulus of the ceramic coating layer is 73.1 GPa and the elastic modulus of the ceramic coating layer is similar to the elastic modulus of the Si oxide layer, the difference in elastic modulus between the two layers is reduced and cracks can be prevented.

In the embodiment of the present invention, the thickness of the ceramic coating layer in the step (iii) may be 30 to 60 mu m.

In the embodiment of the present invention, the critical load of the ceramic coating layer in the step (iii) may be 9N or more.

When forming a ceramic coating layer, the concept of critical thickness is introduced. Critical thickness is the maximum thickness at which the ceramic coating layer can be raised without cracking. The factors that have the greatest influence on the critical thickness are the strength of the ceramic coating layer and the Young's modulus of the Si oxide layer and the ceramic coating layer. In general, since the difference in elastic modulus between the metal material and the ceramic material is large, cracks occur when the ceramic coating layer is formed on the substrate of the metal material due to the difference in the elastic modulus. Therefore, there is a method of introducing a Si oxide layer having a similar elastic modulus to the ceramic coating layer between the two layers by reducing the elastic modulus between the substrate of the metal material and the ceramic coating layer. The Si oxide layer introduced has a similar elastic modulus to the ceramic coating layer The occurrence of cracks can be suppressed. Therefore, the elastic modulus of the Si oxide layer is similar to that of the ceramic coating layer. When the critical load of the ceramic coating layer of the ceramic coating layer is 9N or more, the strength and stress of the ceramic coating layer are increased. Mu m. When the thickness of the ceramic coating layer is less than 30 탆, the chemical properties such as durability and abrasion resistance of the coating layer and mechanical properties such as corrosion resistance may be deteriorated. When the thickness of the ceramic coating layer exceeds 60 탆, the mechanical and chemical properties are improved The thermal conductivity may be lowered.

In an embodiment of the present invention, the ceramic coating layer in step (iii) may be, but is not limited to, being performed with a wet spray coating. The wet coating is a method in which the coating material is mixed with the solvent and transferred to the surface of the material in a state of having a constant viscosity, followed by volatilization and curing of the solvent, which is different from the dry coating in which no solvent is used.

In the embodiment of the present invention, the silicon content of the iron-based substrate containing Si in the step (i) may be 0.1 to 20 wt%. When the content of silicon contained in the iron-based base material is out of the above range, the Si oxide layer can not be formed on the surface of the iron base material to a thickness of 0.1 to 5 탆 and the adhesion with the iron base base material is reduced, Can occur.

In the embodiment of the present invention, the heat treatment in the step (ii) may be performed at 500 to 900 占 폚 for 20 seconds to 300 minutes. When the temperature and time of the heat treatment are out of the above ranges when the Si oxide layer is formed on the surface of the iron-based substrate, the formation of the Si oxide layer on the surface of the iron-based substrate is lowered, which is undesirable and the bonding force may be deteriorated. May be lowered.

In the embodiment of the present invention, H ₂ / H ₂ O (hydrogen partial pressure / steam partial pressure) during the heat treatment in the step (ii) may be performed under the condition of 0.05 to 0.6. When forming the Si oxide layer, H ₂ / H ₂ O is controlled depending on the ratio of the partial pressure of steam to the partial pressure of hydrogen, including a carrier gas such as water vapor, hydrogen, and oxygen. The formation of Fe ₂ SiO ₄ and SiO ₂ oxide layers on the surface of the iron-based substrate can be controlled according to H ₂ / H ₂ O.

In the embodiment of the present invention, the dew point during the heat treatment in the step (ii) may be 20 to 60 ° C. The dew point temperature indicates the amount of water in the air. When the dew point temperature is high, the moisture content of the air is high. When the dew point temperature is low, the moisture content of the air is low. If the dew point temperature is out of the above range, an oxidizing atmosphere can not be formed and peeling may occur during the formation of the oxide layer. In order to maintain the dew point temperature at a temperature outside the above range, It may not be desirable because it requires a device.

In the embodiment of the present invention, the heat treatment in the step (ii) may be performed under an oxidizing atmosphere. The heat treatment causes movement of atoms in the metal to cause a phase change, thereby forming a Si oxide layer on the surface of the iron-based substrate.

According to another aspect of the present invention, there is provided a composite material for a heating and cooking apparatus, which is produced by using a ceramic coating method of a ferrous base material into which a corrosion-resistant Si oxide layer is introduced.

According to another aspect of the present invention, there is provided a heating cooker manufactured using a composite material for a heating cooker.

Hereinafter, examples and experimental examples of the present invention will be described. It should be understood, however, that these embodiments are provided for the purpose of further illustrating the structure and effects of the present invention, and the scope of the present invention is not limited thereto.

[Example 1]

The surface of the iron-based substrate containing Si was subjected to a pretreatment process using a conventional method, and then a gas of 50% hydrogen and 50% nitrogen was passed through a thermostat at a temperature of 30 ° C at 850 ° C for 5 minutes A heat treatment was performed to form a Si oxide layer, and a ceramic coating layer was formed on the Si oxide layer, followed by drying and firing, to form a ceramic coating layer of a ferrous base material into which a Si oxide layer was introduced.

[Experimental Example 1]

In order to analyze the effect of preventing corrosion according to the thickness of the Si oxide layer, it was found that the thickness of the Si oxide layer was 0.1 탆, 0.5 탆 and 1 탆, Of a ceramic coating layer. As a result of conducting an experiment in which the iron base material having the Si oxide layer introduced therein was subjected to a corrosion environment for 3.5 days in a sodium chloride (NaCl) solution for 5 days, no peeling or cracking of the ceramic coating layer occurred and no corrosion occurred.

[Comparative Example 1]

In order to analyze the effect of preventing the corrosion according to the thickness of the Si oxide layer, the thickness of the Si oxide layer was changed to 0.01 탆, 0.03 탆 and 0.05 탆, Of a ceramic coating layer. As a result of experiments in which an iron base material having a Si oxide layer introduced therein was subjected to a corrosion environment for 3.5 days in a sodium chloride (NaCl) solution for 5 days, the time of occurrence of corrosion was slowed and the degree of corrosion was lowered, but the Si oxide layer was formed thin It was confirmed that peeling and cracking of the ceramic coating layer occurred.

[Comparative Example 2]

In order to analyze the effect of preventing corrosion according to the thickness of the Si oxide layer, it was confirmed that the thickness of the Si oxide layer was 2 탆, 3 탆 and 5 탆, Of a ceramic coating layer. As a result of the experiment in which the iron base material into which the Si oxide layer was introduced was formed in a 3.5% sodium chloride (NaCl) solution for 5 days, the time of occurrence of corrosion was slowed and the degree of corrosion was lowered, but the Si oxide layer was formed thick It was confirmed that the ceramic coating layer could not be coated with a coating and the peeling and cracking occurred due to a decrease in the adhesive strength.

[Comparative Example 3]

A ceramic coating layer was formed on the iron-based substrate into which the Si oxide layer was not introduced, and the corrosion environment was formed in a 3.5% sodium chloride (NaCl) solution for 5 days. As a result, the corrosion- In this case, the iron oxide was expanded more than three times in volume and tensile stress was generated in the ceramic coating layer, resulting in peeling and cracking of the ceramic coating layer. It was confirmed that the position where the reaction occurred from the point of corrosion occurred to the iron surface and the corrosion resistance was continuously decreased. Therefore, it has been confirmed that it is necessary to introduce a stable oxide layer between the iron-based substrate and the ceramic coating layer in order to solve the corrosion problem in applying the ceramic coating layer to the iron-based substrate.

It will be understood by those skilled in the art that the foregoing description of the present invention is for illustrative purposes only and that those of ordinary skill in the art can readily understand that various changes and modifications may be made without departing from the spirit or essential characteristics of the present invention. will be. It is therefore to be understood that the above-described embodiments are illustrative in all aspects and not restrictive. For example, each component described as a single entity may be distributed and implemented, and components described as being distributed may also be implemented in a combined form.

The scope of the present invention is defined by the appended claims, and all changes or modifications derived from the meaning and scope of the claims and their equivalents should be construed as being included within the scope of the present invention.

Claims (15)

(i) preparing an iron base material containing Si by pretreatment;
(ii) heat treating the surface of the pretreated iron base material to form a Si oxide layer;
(iii) forming a ceramic coating layer on the Si oxide layer; And
(iv) drying and firing the iron base material on which the ceramic coating layer is formed;
Lt; / RTI >
Wherein the Si oxide layer in step (ii) comprises Fe ₂ SiO ₄ , and SiO ₂ ,
The thickness of the Si oxide layer in the step (ii) is 0.1 to 1 占 퐉,
Wherein the heat treatment in the step (ii) is performed at 500 to 900 占 폚 for 20 seconds to 300 minutes, wherein the corrosion-resistant Si oxide layer is introduced.
delete delete The method according to claim 1,
Wherein the thermal expansion coefficient of the Si oxide layer in the step (ii) is 0.3 to 3 ppm / K, and the thermal expansion coefficient of the ceramic coating layer is not more than the thermal expansion coefficient value of the Si oxide layer. A method of coating a ceramic substrate.
The method according to claim 1,
Wherein the Si oxide layer has an elastic modulus of 60 to 80 GPa.
The method according to claim 1,
Wherein the thickness of the ceramic coating layer in the step (iii) is 30 to 60 占 퐉.
The method according to claim 1,
Wherein the critical load of the ceramic coating layer in the step (iii) is 9N or more.
The method according to claim 1,
Wherein the ceramic coating layer in step (iii) is performed by wet spray coating. ≪ RTI ID = 0.0 > 11. < / RTI >
The method according to claim 1,
Wherein the silicon content of the iron base material containing Si in the step (i) is 0.1 to 20 wt%.
delete The method according to claim 1,
Wherein the H ₂ / H ₂ O is performed at a temperature of 0.05 to 0.6 during the heat treatment in the step (ii).
The method according to claim 1,
Wherein the dew point during the heat treatment in the step (ii) is 20 to 60 ° C.
The method according to claim 1,
Wherein the heat treatment in the step (ii) is performed in an oxidizing atmosphere, wherein the corrosion-resistant Si oxide layer is introduced.
A composite material for a heating and cooking apparatus, which is produced by using a ceramic coating method of a ferrous base material into which a corrosion-resistant Si oxide layer of claim 1 is introduced.
A heating cooker manufactured by using the composite material for a heating cooker according to claim 14.

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